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DIY Stompboxes => Building your own stompbox => Topic started by: frequencycentral on August 09, 2010, 08:13:21 AM

Title: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: frequencycentral on August 09, 2010, 08:13:21 AM
I've had the idea to try a PT2399 chorus ever since I modded my Clari into a Clari Cubed. The challenge with the PT2399 is to get the delay time as short as possible while still having some wiggle room for the LFO injected into pin 6. I've tried PNP, NPN, FET and LDR - fail! The delay time is either too short for the LFO to have any wiggle, or too long and latency is obvious.

So, screw using pin 6, just ground the MF for the shortest possible delay time and instead modulate the vref at pin2. Shortest possible delay with as much LFO wiggle as you want. In fact it has to be tamed down or you're into tape wobble type effects.

I'm still testing this for any failure modes, but so far it seems very stable. Some values may change a little as I fine tune it. TBH I haven't paid any real attention to the filtering caps and their values, as at the speeds this is running at there is no hiss anyway. Those familiar with the PT2399 family of delays will recognise homage to Rebote and the Clari in the input buffer and output section respectively.

(http://i210.photobucket.com/albums/bb292/frequencycentral/LittleAngelMiracle.png)

Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: mth5044 on August 09, 2010, 08:16:12 AM
Where's the submini?  ???

Just kidding. I love it! Great idea. I can't wait to hear clips.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: ~arph on August 09, 2010, 08:27:34 AM
I dig the Vref approach!

Something this easy begs to be tried this week
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: igerup on August 09, 2010, 08:45:54 AM
Interesting. I like the simplicity of the circuit. A board wouldn't even be necessary, unlike most other chorus schemes floating around out there. What opamps did you use?
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Thomeeque on August 09, 2010, 08:49:31 AM
...and instead modulate the vref at pin2.

 :icon_eek: Wow, how did you came to this idea? That's cool! :)

 Few 2c notes:
 
 - You could go with normal non-inverting input buffer with same part-count
 - There's a small DC on mixing resistors (5V - Vref)
 - Depth will probably slightly influence speed
 - You could still have some small blocking cap (1uF?) at Vref pin as datasheet calls for

 T.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: ~arph on August 09, 2010, 08:50:31 AM
That trick is also done in the payback  :icon_surprised:
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Govmnt_Lacky on August 09, 2010, 08:51:49 AM
These might be noob questions but here goes...

Why did you put a Depth pot value of 470K? Why not put it at 500K? I dont know too many places where you can get a Linear 470K pot other than for a Wah.

Also, igerup... what do you mean by a "A board wouldn't even be necessary." How would you build the circuit?
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: frequencycentral on August 09, 2010, 09:05:42 AM
I'm using a NE5532 dual opamp. I used a 470k because here in the UK that's what we use, 500k seemingly being a value available in the US but not here. 500k will work just fine.

How did I come up with the the idea? Well, as I said, I've been trying PNP, NPN, FET and LDR methods into pin 6 but I just couldn't get the resistor value down low enough. So in sheer desperation I thought about actually modulating the +5v feed into pin 1, as I'd notice the delay time 'swoops' if you quickly turn power off and on again - I didn't try it but it got me thinking outside the box. Then I just figured WTF I'll just plug the LFO dirctly into the vref - wobble wobble wobble!

So I'm now waiting for you clever guys out there to suggest any improvements.......
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: igerup on August 09, 2010, 09:31:01 AM


Also, igerup... what do you mean by a "A board wouldn't even be necessary." How would you build the circuit?

There's few enough parts for this not so very complex circuit (lets face it, compared with some other projects on this board it really isn't. No offense meant to frequencycentral with this statement, though) that it can safely be built using the PTP (point-to-point) method. If you have the courage  :icon_wink: to do it is another matter alltogether.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: frequencycentral on August 09, 2010, 09:47:34 AM
I suppose you guys want soundclips yeah?  ::)
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Brymus on August 09, 2010, 09:50:18 AM
OK yet another genius idea from the robot perf boy  8) (I think he is really an alien)
How does this one sound Rick ?
Obviously pretty good if your posting it,and I still have to build one of your phasers first  :icon_evil:
I want your time machine that gives you all the time to do these projects Rick....
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: ~arph on August 09, 2010, 10:13:21 AM
Yes time definately is my biggest constraint.. so If you could post that clip now I can still hear it while I'm at work  :icon_twisted:

Nah, take it easy. I assume it sounds just like all other pt2399 chorusing I've heard.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: frequencycentral on August 09, 2010, 10:17:00 AM
So, I wonder what the delay time of a PT2399 is with pin 6 grounded?
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Thomeeque on August 09, 2010, 10:17:18 AM
I assume it sounds just like all other pt2399 chorusing I've heard.

 Well played! :icon_mrgreen: T.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Thomeeque on August 09, 2010, 10:25:55 AM
So, I wonder what the delay time of a PT2399 is with pin 6 grounded?

 Make recording of some "pop" (e.g. switch some DC at input) and measure distance between original peak and delayed peak in this recording. T.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: ~arph on August 09, 2010, 10:29:06 AM
So, I wonder what the delay time of a PT2399 is with pin 6 grounded?

I thought it needed at least 100R or so to keep too much current from running out.

You can check it of course if you play a short note/tick through it without modulation and then record that and measure the peaks.

Beaten by T.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: frequencycentral on August 09, 2010, 10:43:20 AM
Soundclip!

http://dl.dropbox.com/u/967492/Little%20Angel%20Demo.mp3

Signal path:

Keyboard player playing two chords on a guitar >>> Tele Custom bridge pup (HB) >>> Little Angel (on breadboard) >>> Harley Benton VJ clone >>> Shure SM58 >>> Wavelab

No other processing.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: ~arph on August 09, 2010, 10:48:38 AM
Nice!

That actually sounds different then modulating pin 6. It has more of a vibe feel to it.. come to think of it.. how does it vibe without the clean mixed in?
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Brymus on August 09, 2010, 10:51:40 AM
That sounds GREAT !!
Nice one Rick !
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: mth5044 on August 09, 2010, 10:53:13 AM
Sounds great! Is the sound at 0:11 (the first time the effect is used) at the slowest speed?
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Thomeeque on August 09, 2010, 10:56:37 AM
http://dl.dropbox.com/u/967492/Little%20Angel%20Demo.mp3

 Oh, that sounds promissing*! And I'd say that delay time is pretty short actually (just short enough for proper chorus)! Please, measure it if you have a minute.. Thanks a lot! T.

*to be specific: I miss slower speed and at the slowest speed on the demo I'd say modulation sweep is not ideal**..

**EDIT2: Maybe just increasing of the LFO -> Vref decoupling cap value (10uF on the schemo) would help it.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Brymus on August 09, 2010, 10:57:05 AM
Whats your voltage out the 7805 ?
I have everything except that to try this...
Also hows the volume ?
I noticed no volume pot is it more than unity ?
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: ~arph on August 09, 2010, 11:02:25 AM
I'm going to try this tonight with my favorite sine LFO..

EDIT: The 7805 puts out 5V
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: ~arph on August 09, 2010, 11:05:58 AM
By the way, you do realize a lot of boutique builders will now start modulating pin two right?  :icon_mrgreen:

No relation between voltage and delay time by any chance I suppose?
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: frequencycentral on August 09, 2010, 11:07:04 AM
It has more of a vibe feel to it.. come to think of it.. how does it vibe without the clean mixed in?

Wet only, a little latency is discernable when playing: http://dl.dropbox.com/u/967492/Little%20Angel%20Wet%20Only.mp3

Sounds great! Is the sound at 0:11 (the first time the effect is used) at the slowest speed?

Wet/dry mix, slowest speed, maximum depth, though easy to tweak for even slower and deeper: http://dl.dropbox.com/u/967492/Little%20Angel%20Slowest%20Speed.mp3

Whats your voltage out the 7805 ?
I have everything except that to try this...
Also hows the volume ?
I noticed no volume pot is it more than unity ?

Voltage out of 78L05 is er, 5 volts. Unity gain. I tried a mix pot earlier in the experiment but it screwed with the unity, so I dropped it and went for fixed resistors.

By the way, you do realize a lot of boutique builders will now start modulating pin two right?  :icon_mrgreen:

They will have to ask my permission first surely?  :D
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Renegadrian on August 09, 2010, 11:42:00 AM
Nice clips, Rick!!! I have to try it soon!!! (hopefully in September...)
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Slade on August 09, 2010, 12:03:33 PM
Genius work, you have just released another simple (beginner) chorus for this world. Simple design and sounds fantastic, almost like if you were young.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: 12Bass on August 09, 2010, 12:12:13 PM
Cool!  I'm also curious to know the delay time.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: slacker on August 09, 2010, 12:47:14 PM
Sounds good, I'll have to have a play with that. Presumably the modulation still works if you stick a resistor between pin 6 and ground, so this could also be used to modulate any PT2399 based delay.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: mth5044 on August 09, 2010, 02:04:52 PM
You could modulate Vref and delay time  :o :icon_eek:
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: tiges_ tendres on August 09, 2010, 02:15:47 PM
I had gotten a Belton Brick based delay/reverb to sound pseudo chorus-y by starving the voltage.  I didnt investigate further because if you starve it too far, the chip freaks out and makes random, awful noises.  It kind of made it sound like a Deluxe Memory Man.

There is no reason you couldnt do the same thing to those reverb modules, which probably are just a bunch of PT chips in the brick.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: caress on August 09, 2010, 08:24:46 PM
Sounds good, I'll have to have a play with that. Presumably the modulation still works if you stick a resistor between pin 6 and ground, so this could also be used to modulate any PT2399 based delay.

exactly.  nice to know there's a super simple way to voltage control these...  great job, rick!   :icon_mrgreen:
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Mark Hammer on August 09, 2010, 08:32:53 PM
That is frighteningly good for two chips.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Hides-His-Eyes on August 10, 2010, 04:51:12 AM
A new chapter in modulation pedals, I hope :)
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Thomeeque on August 10, 2010, 05:45:58 AM
So I'm now waiting for you clever guys out there to suggest any improvements.......

 OK ;)

 (http://thmq.mysteria.cz/diystompboxes.com/LA_Thmqs_Notes.gif)

 It's just a quick draft adressing my previous notes mostly, consider at least non-inverting input buffer and "No DC" mod.

 About the LFO buffer - it would be maybe cool to adjust LFO out to work around 2.5V (~PT2399 Vref), then decoupling 10uF cap (which makes shape of sweep dependant on speed in IMO not very pleasant way) could be removed.

 T.

EDIT: GIF slightly updated (+"Placeholders for.."), you may need to refresh page..
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: frequencycentral on August 10, 2010, 06:34:06 AM
Thank you Tomas! I will try these mods soon. I have already added the 'no DC on output' mod, as well as adding a 100R to ground from pin 6 instead of directly grounding it, on Arnoud's advice. Interesting that you suggest non-inverting input buffer, I was under the impression (perhaps mistakenly?) that the output of the PT is inverted, therefore assumed that the inverting buffer I lifted from the Rebote 2 was appropriate? It's important to be mixing in-phase signals here, so I'll try it and report back. As for the LFO, I'm going to have to experiment some more to get it wobbling either side of 2.5v, but yes it will be worthwhile as the 10uF coupling cap certainly does affect the waveform. I see you added LPF's similar to Rebote, probably a good idea. I am also considering adding a 'bright' pot/cap to ground from pin 14. Maybe I should also try adding the wet/dry blend pot back in now there is no DC there!
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: ~arph on August 10, 2010, 06:44:43 AM
I've seen some different cap values for the 9 - 10 and 11 - 12  connections(  datasheet ).
I recall seeing a schematic that had a switchable parallel cap at the pin 9 -10 cap. I believe it was labelled  HP/LP. So that cap supposedly has influence on the bandwith.. I'm curious what different caps do there.

I'm interested in everything pt2399 related as there might be improvements to my 4xpt2399 series delay. (which I still plan to release here)
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Thomeeque on August 10, 2010, 07:49:23 AM
Thank you Tomas!

 My pleasure! :)

I will try these mods soon. I have already added the 'no DC on output' mod, as well as adding a 100R to ground from pin 6 instead of directly grounding it, on Arnoud's advice.

 Was there audible difference? Did you measure delay times with 0 and 100R by any chance?

Interesting that you suggest non-inverting input buffer, I was under the impression (perhaps mistakenly?) that the output of the PT is inverted,

 Both in and out LPFs of PT2399 are inverting so at the output you should be back at the same polarity (if delay line itself does not change it of course - you could actually check it as a part of delay time measuring experiment :)).

therefore assumed that the inverting buffer I lifted from the Rebote 2 was appropriate? It's important to be mixing in-phase signals here, so I'll try it and report back.

 There should be no difference for effect itself - you take dry and wet path from the same point so phase at this point is not relevant. It can by only important for the "outside world" (rest of you setup) in some special circumstances (like processing signal splited for more amps) that phase of passing dry signal is not inverted.. it's sort of "good practise" I'd say..

 Btw. Rebote 2 inverts phase twice (at input and at output), so it's (-1)*(-1)=+1 again :)

 Btw2: Electric Mistress does not care ;)

As for the LFO, I'm going to have to experiment some more to get it wobbling either side of 2.5v, but yes it will be worthwhile as the 10uF coupling cap certainly does affect the waveform. I see you added LPF's similar to Rebote, probably a good idea.

 Yes, it is again case where proper filtering may be important for "outside world" in some special circumstances.

 Again, Electric Mistress does not care ;)

I am also considering adding a 'bright' pot/cap to ground from pin 14. Maybe I should also try adding the wet/dry blend pot back in now there is no DC there!

 Why not? :) Even the "wet/dry blend pot" is one of the features I have found useless on chorus (..and phaser ..and flanger) for me (when it's there I just set it 50:50)..

 T.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: frequencycentral on August 10, 2010, 08:27:06 AM
.....as well as adding a 100R to ground from pin 6 instead of directly grounding it, on Arnoud's advice.
Was there audible difference? Did you measure delay times with 0 and 100R by any chance?

Non that I could hear. I haven't done any measurements yet........


Maybe I should also try adding the wet/dry blend pot back in now there is no DC there!
Why not? :) Even the "wet/dry blend pot" is one of the features I have found useless on chorus (..and phaser ..and flanger) for me (when it's there I just set it 50:50)..

I'd agree with you there, I have no use for wet/dry mix pots, and leave them 50/50. But others may find it useful, so there will be extra pads on the PCB for that option.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: cpm on August 10, 2010, 09:43:14 AM
if only we had a more detailed technical data on the PT2399...
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Grendahl on August 10, 2010, 12:24:00 PM
PT2399 DataSheet for those that need it.
http://www.datasheetcatalog.org/datasheet/PrincetonTechnologyCorporation/mXyzsyzt.pdf (http://www.datasheetcatalog.org/datasheet/PrincetonTechnologyCorporation/mXyzsyzt.pdf)

Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: p_wats on August 10, 2010, 12:38:29 PM
Funny...I was just searching around for a simple chorus to try out. I think I'll have to build this and see how it goes!

Thanks for the excellent design (and for the expert tweaks here and there).
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Renegadrian on August 10, 2010, 01:02:31 PM
Also a PT2399 is cheaper than say a MN3007. And the BOM is smaller than a Zombie.
Having some PTs handy, I think I am gonna get into it. (already working on a vero layout, FIY)
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: frequencycentral on August 10, 2010, 01:32:45 PM
I think it would really benefit any potential builders to wait a while until this design 'stabilises'. I'm hoping to breadboard Tomas's mods later this week - that will be the version to build. BTW, I was 3/4 of the way through a perf/PCB layout when Tomas posted his mods.

I was driving around doing chores earlier, just idly wondering if it would be worthwhile replacing the 2n3904 with an extra opamp stage, then running the two LFO opamps from the 5v supply rail to easily get the LFO wobble bang in the middle of 5v and ground. Then, if we're adding an extra opamp for the LFO, why not add a second dual (or a single quad) and use the spare as an output buffer? This moves away a little from the (desirable) simplicity of the original concept.........Tomas?
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Brymus on August 10, 2010, 01:45:45 PM
I was just looking over the data sheet,
Nothing new to you guys ,I was just noticing that the lower the delay time the lower the THD,which is good IMO especially in this instance.
What would changing out the 100R at pin 6 for a 1-5K pot do to the effect sound ?
It would increase the delay(a little) but is would it sound bad ?
Might it add more(usable?) sounds to the palatte ?
I will try to breadboard this, this week,ahead of other stuff since its so simple.
Maybe I can accidently find something useful to contribute, or at least verify it works for me.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: culturejam on August 10, 2010, 02:27:41 PM
Then, if we're adding an extra opamp for the LFO, why not add a second dual (or a single quad) and use the spare as an output buffer? This moves away a little from the (desirable) simplicity of the original concept.

Just make two layouts:

* Little Angel
* Medium Angel

 :icon_mrgreen:


I really dig the simplicity of the first posted schematic. It sounds great. Of course, improvements are always welcome, but I sure do love a small, tidy layout.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: JKowalski on August 10, 2010, 02:31:23 PM
And I thought the Vref on the chip was buffered...? Even if it isn't, I have no idea how you are getting adjustment in delay times by modulating Vref.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: frequencycentral on August 10, 2010, 02:52:03 PM
What would changing out the 100R at pin 6 for a 1-5K pot do to the effect sound ?
It would increase the delay(a little) but is would it sound bad ?

Look at the data sheet:

1.08k = 40.6ms
4.9k = 86.3ms

..too long for chorus. But.....

0.5k = 31.3ms

0.1k = ?

0.0k = ??

....so for chorus it is desirable to get the delay time as low as you can go.

And I thought the Vref on the chip was buffered...? Even if it isn't, I have no idea how you are getting adjustment in delay times by modulating Vref.

Yeah, the block diagram on the data sheet shows the vref only connected to the opamps. But it works........
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Brymus on August 10, 2010, 03:02:48 PM
So maybe a 1k pot might be useful then,?
I will try myself and report back.
FWIW I havent done anything with LFO's or modulation of any kind yet so this is new to me. :icon_redface:
And really thanks for posting another useful circuit Rick,and for everyone helping (Tomeque,ect)
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: DougH on August 10, 2010, 03:14:43 PM
Cool project!

Okay, now this is funny:

http://www.taydaelectronics.com/servlet/the-63/PT2399-2399-Echo-Audio/Detail (http://www.taydaelectronics.com/servlet/the-63/PT2399-2399-Echo-Audio/Detail)

Okay.. Seems about right.


http://compare.ebay.com/like/260453494074?ltyp=AllFixedPriceItemTypes&rvr_id=122814086475&crlp=1_263602_263632&UA=WXF%3F&GUID=cb6d3f2a10c0a041b291fd31fff7dccf&itemid=260453494074&ff4=263602_263632 (http://compare.ebay.com/like/260453494074?ltyp=AllFixedPriceItemTypes&rvr_id=122814086475&crlp=1_263602_263632&UA=WXF%3F&GUID=cb6d3f2a10c0a041b291fd31fff7dccf&itemid=260453494074&ff4=263602_263632)

Not bad. About what you would expect...


http://compare.ebay.com/like/270597040866?ltyp=AllFixedPriceItemTypes&rvr_id=122835671300&crlp=1_263602_263632&UA=WXF%3F&GUID=cb6d3f2a10c0a041b291fd31fff7dccf&itemid=270597040866&ff4=263602_263632 (http://compare.ebay.com/like/270597040866?ltyp=AllFixedPriceItemTypes&rvr_id=122835671300&crlp=1_263602_263632&UA=WXF%3F&GUID=cb6d3f2a10c0a041b291fd31fff7dccf&itemid=270597040866&ff4=263602_263632)

WTF?!?  ??? :icon_rolleyes: :icon_mrgreen: :icon_mrgreen: :icon_mrgreen:
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: frequencycentral on August 10, 2010, 03:16:24 PM
I buy mine fom Tayda, so cheap you can buy a half dozen without breaking a sweat....

....which affords one the luxury of doing unlikely things to the wrong pins (without worrying about toasting it) in the hope of discovering something new!
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: armstrom on August 10, 2010, 03:35:56 PM
Not bad. About what you would expect...
http://compare.ebay.com/like/270597040866?ltyp=AllFixedPriceItemTypes&rvr_id=122835671300&crlp=1_263602_263632&UA=WXF%3F&GUID=cb6d3f2a10c0a041b291fd31fff7dccf&itemid=270597040866&ff4=263602_263632 (http://compare.ebay.com/like/270597040866?ltyp=AllFixedPriceItemTypes&rvr_id=122835671300&crlp=1_263602_263632&UA=WXF%3F&GUID=cb6d3f2a10c0a041b291fd31fff7dccf&itemid=270597040866&ff4=263602_263632)

WTF?!?  ??? :icon_rolleyes: :icon_mrgreen: :icon_mrgreen: :icon_mrgreen:

that's for 460 pcs :)
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: slacker on August 10, 2010, 03:53:53 PM
Just breadboarded the first version and it sounds pretty good, the chorus is quite subtle on the slower setting but it's a nice sound definitely worth exploring. Thanks for sharing it Rick.
I wouldn't say the delay time is significantly shorter than you can get by modulating the resistance on pin 6, but it does the job a lot simpler.

I was driving around doing chores earlier, just idly wondering if it would be worthwhile replacing the 2n3904 with an extra opamp stage, then running the two LFO opamps from the 5v supply rail to easily get the LFO wobble bang in the middle of 5v and ground. Then, if we're adding an extra opamp for the LFO, why not add a second dual (or a single quad) and use the spare as an output buffer? This moves away a little from the (desirable) simplicity of the original concept.........Tomas?

That should work fine, you'll need to use something like an LM358 for the LFO though, a TL072 style opamp won't run off 5 volts. If you're doing that I would change the LFO for a standard 2 opamp type, like in the Echo Base, that will give a "better" triangle output and uses the same number of parts as buffering the LFO you have already.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: clamup1 on August 10, 2010, 04:30:03 PM


i cant wait to give this one a try, its #3 on the list
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: anchovie on August 10, 2010, 05:17:20 PM
0.5k = 31.3ms

That's actually 0.5R, so I think that's their way of saying it's as low as you can go!
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: frequencycentral on August 10, 2010, 05:59:17 PM
0.5k = 31.3ms

That's actually 0.5R, so I think that's their way of saying it's as low as you can go!

Damn, you're right! I completely mis-read that! Thank you!
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Renegadrian on August 10, 2010, 06:07:18 PM
Not bad. About what you would expect...
http://compare.ebay.com/like/270597040866?ltyp=AllFixedPriceItemTypes&rvr_id=122835671300&crlp=1_263602_263632&UA=WXF%3F&GUID=cb6d3f2a10c0a041b291fd31fff7dccf&itemid=270597040866&ff4=263602_263632 (http://compare.ebay.com/like/270597040866?ltyp=AllFixedPriceItemTypes&rvr_id=122835671300&crlp=1_263602_263632&UA=WXF%3F&GUID=cb6d3f2a10c0a041b291fd31fff7dccf&itemid=270597040866&ff4=263602_263632)

WTF?!?  ??? :icon_rolleyes: :icon_mrgreen: :icon_mrgreen: :icon_mrgreen:

that's for 460 pcs :)

Collective buy?!
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: frequencycentral on August 10, 2010, 08:15:35 PM
So, assuming the PT is running close to the fastest it can. At 5 volts. The datasheet says it can handle 6.5 volts absolute maximum. The question is, if we give it 20% more volts (ie 6 volts) are we also then going to over-clock it into 20% faster delay time? Theoretically we could shave off 6.4ms........?
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Mugshot on August 10, 2010, 09:47:08 PM
hey rick, what about setting the resistance to ground of pin 6 variable instead of being shunted to ground? would it get it closer to a modulated delay something?
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: frequencycentral on August 11, 2010, 05:22:29 AM
hey rick, what about setting the resistance to ground of pin 6 variable instead of being shunted to ground? would it get it closer to a modulated delay something?

Yes, but slacker's Echo Base does modulated delay better, and with multiple repeats and a host of other useful functions. But with Little Angel I think having any more than the absolute minimum resistance between pin 6 and ground is missing the point. Little Angel is a chorus, so it's desirable to keep the delay time as short as possible.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: cpm on August 11, 2010, 05:38:47 AM
Yes, but slacker's Echo Base does modulated delay better, and with multiple repeats and a host of other useful functions. But with Little Angel I think having any more than the absolute minimum resistance between pin 6 and ground is missing the point. Little Angel is a chorus, so it's desirable to keep the delay time as short as possible.

and... what about feedback,
maybe a small, frequency controlled feedback may add interesting effects
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: markeebee on August 11, 2010, 06:24:50 AM
Then, if we're adding an extra opamp for the LFO, why not add a second dual (or a single quad) and use the spare as an output buffer? This moves away a little from the (desirable) simplicity of the original concept.

Just make two layouts:

* Little Angel
* Medium Angel



Or maybe Little Angel and Little Devil?  Then Rick could retrospectively enter the 666 competition (as he made the rules up as he went along anyway) and win himself a Murder One!

Oh hang on....from the 666 comp thread.....

Thanks rick. :) The overall prize aside, can we expect any "work" from you???

Nothing demonic sorry. I'm working on angelic!


*****CLANG****  The penny drops.


I love the sound of the clips, Rick.  Not usually a fan of chorus but I really like the organic-ness of this.  I take your point about Echo Base doing modulated delay better , but I think I'd like a variable R at pin 6 so that I get a really really nice sounding chorus (primarily) with the added bonus of mod delay (secondary).

Good work, sailor.  As always.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: frequencycentral on August 11, 2010, 06:52:12 AM
*****CLANG****  The penny drops.

Hahahaha - well spotted sir!

I think this project will continue on two seperate paths:

Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: ~arph on August 11, 2010, 07:03:47 AM
I'd increase the max available depth of the effect. What you have now I'd say is in the middle of what I'd want.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: frequencycentral on August 11, 2010, 07:28:31 AM
I'd increase the max available depth of the effect. What you have now I'd say is in the middle of what I'd want.

That woud just require the 100k at pin 2 to be reduced to say 47k.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: ~arph on August 11, 2010, 07:38:58 AM
Yes, I know, but I'd include that in the minimal version so it's a bit more versatile without increasing circuit complexity  ::)
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: DougH on August 11, 2010, 07:58:15 AM
Not bad. About what you would expect...
http://compare.ebay.com/like/270597040866?ltyp=AllFixedPriceItemTypes&rvr_id=122835671300&crlp=1_263602_263632&UA=WXF%3F&GUID=cb6d3f2a10c0a041b291fd31fff7dccf&itemid=270597040866&ff4=263602_263632 (http://compare.ebay.com/like/270597040866?ltyp=AllFixedPriceItemTypes&rvr_id=122835671300&crlp=1_263602_263632&UA=WXF%3F&GUID=cb6d3f2a10c0a041b291fd31fff7dccf&itemid=270597040866&ff4=263602_263632)

WTF?!?  ??? :icon_rolleyes: :icon_mrgreen: :icon_mrgreen: :icon_mrgreen:

that's for 460 pcs :)

Oh my goodness, you're right.  :icon_redface: :icon_redface: :icon_redface:

I didn't see that... I just checked the "quantity" at the top. My bad.

And sorry for the thread derail.  :icon_redface: Carry on...
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Renegadrian on August 11, 2010, 07:59:13 AM
Yes, I know, but I'd include that in the minimal version so it's a bit more versatile without increasing circuit complexity  ::)

A switch a one more res. should keep it simple yet
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: frequencycentral on August 11, 2010, 10:20:27 AM
Fresh from the breadboard:

Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: p_wats on August 11, 2010, 10:42:28 AM
I'm with Rick on this one: keep it as simple as possible for now, as this could definitely be the easiest chorus build around.

...but once that's verified then let the feature tweaks commence to see how far we can take this thing!

Rick, would you say your initial schematic is ripe for people like myself to perf to our hearts content (you had suggested waiting earlier)? Thanks again!
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: frequencycentral on August 11, 2010, 10:56:54 AM
Rick, would you say your initial schematic is ripe for people like myself to perf to our hearts content (you had suggested waiting earlier)? Thanks again!

I just updated the schematic and reloaded it into photobucket, it should show up in post #1 of this thread if you refresh. It says version 2 on it. At this very moment a friend of mine in NJ is populating a PCB made from my layout. Once he verifies it I will post it.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Renegadrian on August 11, 2010, 12:49:35 PM
no version 2 even on refresh... :icon_frown:
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: frequencycentral on August 11, 2010, 12:59:25 PM
no version 2 even on refresh... :icon_frown:

Yeah I noticed that. I deleted the original and loaded the new one under the same name, so it should be showing up. Probably an issue with photobucket. If it doesn't refresh in a few hours I'll upload it under an new name and repost it. I just didn't want to confuse the thread with many different schematics.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: p_wats on August 11, 2010, 01:04:38 PM
If it doesn't refresh in a few hours I'll upload it under an new name and repost it. I just didn't want to confuse the thread with many different schematics.

Nice! Works for me now. This will have to go to the top of my list...
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: frequencycentral on August 11, 2010, 01:25:26 PM
Hmm, still not refreshing for me...

(http://i257.photobucket.com/albums/hh218/reverse_engineer/angel2.jpg)
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: soggybag on August 11, 2010, 01:57:33 PM
Very inspiring, great work. I love this chip. Pin 2 is still sort of a mystery to me. What exactly does this do?
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: doug deeper on August 11, 2010, 02:26:02 PM
awesome!
add a blend pot and a square/triangle option and a delay time pot and you pretty much have the pitch pirate.
does this mean i can modulate pin 2 on my next pedal?
 ;D
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: culturejam on August 11, 2010, 02:28:06 PM
This mutha is a verified, working beast of a chorus.  :icon_mrgreen:

With the depth control very low, the effect is quite subtle at lower LFO speeds. With the Speed slow and the depth cranked, you get classy shimmery (ever so slightly metallic) chorus tones. But still kinda unique. And with the Depth and Speed both high, the overall effect is more like a vibey chorus. There is a bit of a pulse and throb at that setting.

Very versatile and highly recommended. I simply cannot believe something this simplistic (parts-wise) can sound this big and great.

Super kudos to Rick.  ;D

This is the simple version, as built by me earlier today and verified just now. I'll play around some more with the settings and see if there are any dead spots, but my initial tweaking yielded only positive results.

(http://i257.photobucket.com/albums/hh218/reverse_engineer/angel3.jpg)
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: frequencycentral on August 11, 2010, 02:30:34 PM
Verified schematic and layout:

(http://i210.photobucket.com/albums/bb292/frequencycentral/LittleAngelMiracle-1.png)
(http://i210.photobucket.com/albums/bb292/frequencycentral/LittleAngelPCB.gif)
(http://i210.photobucket.com/albums/bb292/frequencycentral/LittleAngelPnP.gif)
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: culturejam on August 11, 2010, 02:34:22 PM
One important note that might save people some time:

The orientation of the voltage regulator on the layout is correct for the 78L05 version.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: markeebee on August 11, 2010, 02:51:35 PM
I love you, Rick. I just do.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: ~arph on August 11, 2010, 02:53:42 PM
And now you've all tried that..

try this:  remove the 1n cas between 13-14 and 15-16: no audible difference -> saves two components

Make the two caps between 9-10 and 11-12 -> 220nF
Make the two caps to ground from 7 and 8 small.. say 10 - 22 nF

sounded a bit better to my ears.
Still I think it's not really chorusy sounding, more vibey...


Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: slacker on August 11, 2010, 02:59:27 PM
Little mod for anyone who's interested try changing the resistor connected to pin 15 to 22k, that makes the wet side a bit louder and sounds more chorusy to me. It might mess with to overall level though.
Title: Re:
Post by: earthtonesaudio on August 11, 2010, 03:08:37 PM
I would caution that it might be harmful to the chip to exceed Vcc at any pin, including pin 2.  It might be worthwhile to add a clamping zener from pin 2 to ground, or else limit the LFO output in some other way.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: frequencycentral on August 11, 2010, 03:22:21 PM
Super kudos to Rick.  ;D

And super kudos back at culturejam for etching, drilling, populating and testing the PCB layout all in one day!
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: dmc777 on August 11, 2010, 03:40:52 PM
Sounds great! Anyone know how to go about adding a level or blend control into this? 
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: culturejam on August 11, 2010, 04:30:32 PM
Something I just noticed is that the Depth control also has an affect on tone. As Depth is turned down, mids are accentuated, and I think maybe highs are attenuated just a hair. With Depth more than about half-way, tone does not seem to be affected (ie - it sounds like the bypassed tone, just modulated).

There are some really cool sounds in this thing, although I probably wouldn't classify it as true chorus. It's got chorus settings, and it's got vibe settings. And it also does some other stuff.

With both Depth and Speed at minimum, it just makes the guitar sound a little bigger and fuller.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: culturejam on August 11, 2010, 04:57:56 PM
I had a partially gutted enclosure already painted and it had two knob holes drilled....

All I had to do was solder a few wire, slap on some stamp artwork, and take photos.  :icon_mrgreen:


(http://i257.photobucket.com/albums/hh218/reverse_engineer/Little_Angel_01.jpg)



(http://i257.photobucket.com/albums/hh218/reverse_engineer/Little_Angel_02.jpg)



(http://i257.photobucket.com/albums/hh218/reverse_engineer/Little_Angel_03.jpg)
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Slade on August 11, 2010, 06:26:12 PM
(http://i257.photobucket.com/albums/hh218/reverse_engineer/Little_Angel_03.jpg)
Cheers! That was fast! :icon_cool:
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: soggybag on August 11, 2010, 07:26:32 PM
The length of the delay can describe the difference between phase shift to chorus to flange then on to real delay. I wonder if increasing the resistance on pin 6 a little might move the whole thing into flange territory?
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: frequencycentral on August 11, 2010, 08:00:56 PM
Very inspiring, great work. I love this chip. Pin 2 is still sort of a mystery to me. What exactly does this do?

According to the datasheet pin 2 is the vref for the internal opamps.

Sounds great! Anyone know how to go about adding a level or blend control into this?  

You could add blend control by cutting the traces to the left of C12 and C15. Take a suitable pot (10k or 22k maybe?), connect C12 to lug 1, C15 to lug 3, connect lug 2 to ground via a 100k resistor. Take you output from lug 2.

The length of the delay can describe the difference between phase shift to chorus to flange then on to real delay. I wonder if increasing the resistance on pin 6 a little might move the whole thing into flange territory?

Increasing the resistance on pin 6 will take it further away from chorus into short delays. The PT2399 really has too high a minimum delay time to do flanging, as flanging requires shorter delays than chorus. Maybe something interesting to try would be to feed the dry signal through a second PT2399 set to a very short fixed delay, that way the modulated delay would wobble either side of the fixed delay. Perhaps it would sound like flanging, but with ~30ms latency.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: soggybag on August 11, 2010, 08:10:02 PM
What's happening here when you're modulating the VRef on pin 2? Seems like this shouldn't change the delay time. Is it effecting the signal passing through the two internal op-amps, creating a sort of phase shift on these?
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: frequencycentral on August 11, 2010, 08:15:13 PM
What's happening here when you're modulating the VRef on pin 2? Seems like this shouldn't change the delay time. Is it effecting the signal passing through the two internal op-amps, creating a sort of phase shift on these?

Search me! I was hoping some clever guy would come tell us. My instinct tells me that the internal VCO must also be referencing the vref. The datasheet should be called '101 things you'll never know about the PT2399 and other mysteries'.

Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Earthscum on August 11, 2010, 08:17:55 PM
looks to me like you are wobbling the Vref only on the filters. Since they are all inverting, they all wobble the signal back and forth, so you are getting a phasing of the filters moving away and towards each other...

I don't know. Makes sense to me... like wwobbling an all pass filter.

EDIT: BTW, awesome idea! I've been looking for something kewl like this... I've been trying to figure out something awesome to make for my bass with the delay. This overqualifies, IMHO. Most delays cater to guitar, and well... bass acts a bit differently   ;D
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: frequencycentral on August 11, 2010, 08:26:04 PM
looks to me like you are wobbling the Vref only on the filters. Since they are all inverting, they all wobble the signal back and forth, so you are getting a phasing of the filters moving away and towards each other...

I don't know. Makes sense to me... like wwobbling an all pass filter.

There is way way way more wobble available than a few dozen all pass filters could muster. This is not phasing. I have a 14 stage phaser on my other breadboard (http://www.diystompboxes.com/smfforum/index.php?topic=84968.msg719516#msg719516) that can't do these tricks.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: soggybag on August 11, 2010, 08:33:57 PM
Quote
Search me! I was hoping some clever guy would come tell us. My instinct tells me that the internal VCO must also be referencing the vref. The datasheet should be called '101 things you'll never know about the PT2399 and other mysteries'.

Thanks for the reply, as long as we're all in the dark I'm OK. The use of pin is still a total mystery.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Earthscum on August 11, 2010, 08:39:32 PM
There is way way way more wobble available than a few dozen all pass filters could muster. This is not phasing. I have a 14 stage phaser on my other breadboard (http://www.diystompboxes.com/smfforum/index.php?topic=84968.msg719516#msg719516) that can't do these tricks.

Nice... did I miss sound clips somewhere in the thread, or do you have any? I'm really curious now. I'd go breadboard it, but my roomie camped the TV as soon as he got off work like a baby. That's where all my stuff is at, and don't wanna bug him.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Mugshot on August 11, 2010, 08:42:37 PM
funny, i breadboarded this last night (it's morning here), and thought the 500K depth pot wasnt really useful so changed it to 250K, but thought the minimum depth was still lacking prominence of the chorused signal, so i thought maybe trimming the 100K minimum depth resistor to 47K would give me a more prominent chorus. and then here im reading it was already changed to 33K!  :icon_lol:

i also tried bridging pins 16 and 14 of the PT chip with a 47K resistor for feedback, but wasnt convinced. will try insteda the 33K minimum depth mod later tonight. nice one Rick!
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: culturejam on August 11, 2010, 09:30:11 PM
Clip!

http://www.archive.org/details/LittleAngel-Pt2399-basedChorus

Here's what's up:

Same basic progression each time.

First clean >
Speed 12:00 / Depth 2:00 >
Speed 12:00 / Depth MAX >
Speed turned from min to much higher / Depth MAX >

And then I just move around and try to show the main types of tones you can get. I think I did a total of maybe 8 settings or so.

And then clean again.

Straight into Garage Band through a UX1 with a hint of (software) reverb.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: 12Bass on August 11, 2010, 09:38:34 PM
From that sound of the most recent sample, given how it is phasing the midrange, I'd guess that the delay is under 20 ms. 
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Earthscum on August 11, 2010, 09:45:47 PM
Holy wow! Ok, I hear what you're talking about now. That's definitely a mod I'll be using... and refusing to my buddies! I gotta keep my rig sounding the kewlest...  ;D

Hats off to both of ya!
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: $uperpuma on August 12, 2010, 12:51:32 AM
This is very cool.  Breadboard time!
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: ~arph on August 12, 2010, 02:11:35 AM
And give the changes in post #81 a try  8)
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: frequencycentral on August 12, 2010, 07:11:33 AM
try this:  remove the 1n cas between 13-14 and 15-16: no audible difference -> saves two components

I could remove the 13/14 cap without trouble, but removing the 15/16 cap caused noise. Haven't played with the other values yet.

Little mod for anyone who's interested try changing the resistor connected to pin 15 to 22k, that makes the wet side a bit louder and sounds more chorusy to me. It might mess with to overall level though.

Yes this certainly works! Although the effect is now higher than unity, but easily tamed back.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: ~arph on August 12, 2010, 07:57:52 AM
You can make it more vibey if you apply some of that modulation to pin six too  ;D
The 22k in the input stage mod works really well too..
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: culturejam on August 12, 2010, 01:05:49 PM
The 22k in the input stage mod works really well too..

Which resistor are you referring to? By that I mean which part number on the Little Angel schematic are you referring to?

Thanks
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: slacker on August 12, 2010, 01:18:46 PM
It's R5 on the layout, the 10k connected to pin 15 of the PT2399.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Brymus on August 12, 2010, 02:11:40 PM
This just keeps getting better and better....
Nice build and clips Forrest !!
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Talison on August 12, 2010, 02:40:54 PM
how about a Vero layout?    ;D
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Brymus on August 12, 2010, 03:52:23 PM
Hope this isnt a dumb question  :-[
But what about adding the Taptation controller that TTG just released ?
Would that allow the phasing/modulation to be "controlled" a bit more ?

EDIT posts =  1111  ;D
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: culturejam on August 12, 2010, 04:27:11 PM
It's R5 on the layout, the 10k connected to pin 15 of the PT2399.

Thanks!
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Renegadrian on August 12, 2010, 06:00:20 PM
how about a Vero layout?    ;D

I was working on it, but Rick adviced it's better to have a definitive version and not a work in progress.
As soon as we can say "that's the final version" I am gonna finish my vero layout.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: frequencycentral on August 12, 2010, 06:06:31 PM
how about a Vero layout?    ;D

I was working on it, but Rick adviced it's better to have a definitive version and not a work in progress.
As soon as we can say "that's the final version" I am gonna finish my vero layout.

I think what we've got now is close enough already. After all, a verified PCB layout now exists, so why not a vero?

So that's the LITE version wrapped up, give or take a few values here and there. So what features do we want in the ELITE version?
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: culturejam on August 12, 2010, 07:18:40 PM
So that's the LITE version wrapped up, give or take a few values here and there. So what features do we want in the ELITE version?

Adjustable max delay time.  ;D
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: zambo on August 12, 2010, 07:55:08 PM
Thanks for this cool project Rick.
P.S. I also believe that you are an alien
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Renegadrian on August 12, 2010, 09:30:54 PM
how about a Vero layout?    ;D

I was working on it, but Rick adviced it's better to have a definitive version and not a work in progress.
As soon as we can say "that's the final version" I am gonna finish my vero layout.

I think what we've got now is close enough already. After all, a verified PCB layout now exists, so why not a vero?

All right, I'll post it in some days then!!!
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: culturejam on August 12, 2010, 09:45:49 PM
Another idea for the ELITE version:

How about a toggle switch to apply the LFO wobble to pin 6 as well as pin 2?

And what about having a trimmer + resistor in place of the 100K resistor to ground on the output? Could be like a "level" control of sorts to help match unity volume.  Unless you already have output volume control via op amp in the works for the Elite.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Brymus on August 12, 2010, 09:50:15 PM
Why not a set of filters to pass the mids and/or bass through un-modulated with a blend control ?
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Earthscum on August 13, 2010, 12:59:07 AM
How about a toggle switch to apply the LFO wobble to pin 6 as well as pin 2?

And what about having a trimmer + resistor in place of the 100K resistor to ground on the output? Could be like a "level" control of sorts to help match unity volume.  Unless you already have output volume control via op amp in the works for the Elite.

I tried it. Didn't really do much. Gotta build a second LFO for it to modulate at different speeds, then you would notice a difference.

Also, I just used a 100k volume pot and started it out on high, like 100k to ground. I ended up having to turn it down a hair (to probably about 75k) to hit unity. I'm also using a bass to test this (since that's what I'm building it for), and noticed the B and E strings don't get as much of the effect as A and higher.

I noticed, though, that my 500k pot only had about 1/8 turn as usable range... after I dropped the 33k. With the 33k in place, I was getting no wobbling. I triple checked everything, so not sure why it does this. Also, my 100k has only about 1/4 usable area. I'm done with it for the night, but if anyone has any suggestions, I'll try them out tomorrow.

Edit to add: I'm using TL072. Could this be part of it? All I have on hand at the moment is TL072's & 4's, 741's, TL082's, and LM324's.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: frequencycentral on August 13, 2010, 04:12:15 AM
I have given my permission for guitarpcb.com to do a run of PCBs:

http://www.guitarpcb.com/apps/webstore/products/show/1690146

(http://img204.imageshack.us/img204/6156/littleangelcopper.jpg)
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: culturejam on August 13, 2010, 10:57:02 AM
I noticed, though, that my 500k pot only had about 1/8 turn as usable range... after I dropped the 33k. With the 33k in place, I was getting no wobbling. I triple checked everything, so not sure why it does this. Also, my 100k has only about 1/4 usable area. I'm done with it for the night, but if anyone has any suggestions, I'll try them out tomorrow.

On my build, I'm noticing that in order to hear how the lower range of either pot sweep is effecting things, the other control has to be set closer to maximum. For example, the change in Speed seems very subtle for the first half turn with Depth low, but when Depth is cranked, the Speed changes are far more noticeable.

Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: slacker on August 13, 2010, 12:16:26 PM
I might have figured out how changing the bias voltage effects the delay time.
If you look at the block digram in the datasheet you'll see the output of the OP1 opamp (pin 9) is connected internally to the positive input of the COMP, presumably this is a comparator of some sort. The + input of the OP1 opamp is connected to the bias voltage, so changing that will change the output of the opamp and as the output is connected to the COMP it will have an effect on the signal coming out of COMP.
If COMP is like a comparator then changing the bias voltage would change the pulse width of the output which could then have some effect further down the line in the digital part of the chip.
Or maybe not who knows :)
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: earthtonesaudio on August 13, 2010, 01:53:41 PM
I don't think so.  Changing Vref causes no differential voltage change at the inputs of the comparator, because both its inputs are driven by opamps biased at Vref, both of which have a DC gain of +1.  This does not apply at high frequencies, but at LFO rates I think it does.

I think it's more likely that pin 2 is somehow tied to the internal VCO's circuitry.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: slacker on August 13, 2010, 02:16:46 PM
Good point I missed that, yeah the most likely thing is that the VCO has a connection to the bias voltage.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Earthscum on August 13, 2010, 02:48:40 PM
On my build, I'm noticing that in order to hear how the lower range of either pot sweep is effecting things, the other control has to be set closer to maximum. For example, the change in Speed seems very subtle for the first half turn with Depth low, but when Depth is cranked, the Speed changes are far more noticeable.

Yep, I'm getting the exact same thing. I have to have them both within a certain range for them to be usable. If either one is out of the range, there's no audible modulation. This is actually the LFO itselfm it seems... I've tried different chips and get the same result. Tried different pots as well.


I just noticed... I'm an idiot. My 500k is audio tapered. I flipped it around the right way and now have more useable range from it.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Earthscum on August 13, 2010, 03:00:46 PM
Ok, so I figured out if you replace the 10k between pin 14 and the .01 with a 50k-100k pot, you can adjust the mix. I ended with a great mix at around 27k, This actually cured most of my problem.  As well, I dropped my 33k to ground down to 27k to get that top lope at full pot rotation. I may pop in a TL074 and make an LFO buffer and output buffer/mixer. It feels like that would cure a bunch of the LFO interaction issues that I'm experiencing.

The delay output pot is actually nice... I can sweep from a perfect chorus mix to flanging sounds to a dry and subtle sound.

The LA works pretty good for bass, except like I noted before, you lose effect on the lower notes. I tried a bazz fuss before it and it really gets snazz and pizazz! This actually is a nice thing for some songs where you want the low end to sit back a bit, but your hig strings just have too much bite. This makes the high end shimmer and actually settles it into the mix a bit better. I just gotta redo the input stage to get my punch back.

Again, big thumbs up on this one! This is a kewl little project!
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: culturejam on August 13, 2010, 03:57:56 PM
Ok, so I figured out if you replace the 10k between pin 14 and the .01 with a 50k-100k pot, you can adjust the mix. I ended with a great mix at around 27k, This actually cured most of my problem. 

I'm building another one soon for mods/tweaks testing, so I'll give this a try.

Quote from: Earthscum
As well, I dropped my 33k to ground down to 27k to get that top lope at full pot rotation.

Funny, I just mentioned to Rick that maybe 27K would work as well, since he said 22K was a bit too low.  :)
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Earthscum on August 14, 2010, 03:57:42 AM
Aye, I think it's probably too low for a complete build. I think the 33k is just about right... actually, I kept tuning, pulling and measuring and ending up around 29.5k for my personal lowest sweet spot. 27k seemed to begin introducing a small bit of audible lfo clicking, and lower by about about 5 k was just a bit too much for me to just slam the pot all the way.

I noticed an interaction while playing through my TKO, though. I put a 50k to ground from pin 6 (will probably go with a 10K), and when I used my mixer pot (which, BTW, should have a min setting resistor... it lets alot of hiss through at close to full wet) I could get a nice clear wet sound.

When I play my bass, the lower notes aren't coming through as well as the higher notes due to the time. For bass, this isn't necessarily bad. Basically at fastest delay, the lowest notes are mixing more readily at the output. When I set the mixer just right, I could get even mix, and tossed on a low pass before the junction from the output of PT. Now I have delayed highs, with my normal lowend punch! That's awesome for bass! The delay is a little over the top, but every part of this is a little bit of something kewl. Faux Delay, faux semi-flanger, faux Sonic Maximizer, and a space noise signal destroyer in one box. Seriously, my GF is into EBM and plays a bit of bass, and nearly started drooling as I swept through some settings.

Hit the input with a bazz fuss or other decent sounding dist, and this thing kills! Plain BF sounds gigantic. The filtering shaves off all the highs. Perfect circuit, IMHO, if ya want to add a small switchable dist. inside a box. Really, it sounded like I've never heard it before  ;D
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: frequencycentral on August 14, 2010, 05:47:04 AM
As the PT can handle up to 6.5v, I'm still wondering if delivering more voltage than the accepted 5v would result in an over-clocked VCO and even shorter delay times.

actually, I can answer that. I tried that a couple years ago and according to my notes

with pin 6 grounded,
5V supply = 24ms
6V            = 18ms
6.5V         = 16.5ms
7V            = 15ms
7.5V         = 14ms
8.5V         = dead chip

also current draw nearly doubles from 28mA @ 5V to 58mA @ 6.5V

hope that helps


So who's going to replace the 7805/78L05 with a 7806/78L06?  :icon_biggrin:
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: frequencycentral on August 14, 2010, 06:45:42 AM
So, assuming the PT is running close to the fastest it can. At 5 volts. The datasheet says it can handle 6.5 volts absolute maximum. The question is, if we give it 20% more volts (ie 6 volts) are we also then going to over-clock it into 20% faster delay time? Theoretically we could shave off 6.4ms........?

 :icon_mrgreen:
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: frequencycentral on August 14, 2010, 06:50:23 PM
.....and the PCB apparently will fit in a 1590A! This might well be my excuse to try my hand at a 1590A build. solderman? danielzink? valoosj?
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: culturejam on August 14, 2010, 07:06:26 PM
.....and the PCB apparently will fit in a 1590A!

I would've never guessed that.  :icon_eek:

Actually, I was thinking it would be cool to have a layout that takes advantage of 1/8-watt resistors and multi-layer ceramic caps.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: culturejam on August 14, 2010, 08:38:24 PM
So, assuming the PT is running close to the fastest it can. At 5 volts. The datasheet says it can handle 6.5 volts absolute maximum. The question is, if we give it 20% more volts (ie 6 volts) are we also then going to over-clock it into 20% faster delay time? Theoretically we could shave off 6.4ms........?

 :icon_mrgreen:

Did it work?  ??? :)
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: danielzink on August 15, 2010, 12:56:47 AM
.....and the PCB apparently will fit in a 1590A! This might well be my excuse to try my hand at a 1590A build. solderman? danielzink? valoosj?

I'm following the thread...yes yes.......I'm waiting for all "the dust to settle" and all the mods be sorted etc.

;)


DZ
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Earthscum on August 15, 2010, 10:59:03 AM
So... am I the first? I used this thing live, and it's so sweet!

I left to buy parts at 11:15 yesterday morning. Luckily I had an old MXR Auto-Q case that was drilled already. I actually finished, plugged it in to test, congratulated myself and my guitarist walks in. 5:00, bar opens at 6... I can't believe I actually made it, and it worked! lol.

BTW, I ended up using this thing on about half my songs last night. We had a buddy sitting in, so I had to  pit the Little Angel up against a G-K Roto Sphere. Rick, this is awesome... it actually held it's own! I was able to tweak the LFO and fill the space between the dry guitar, and Brooks' RS, without making even myself cringe. I was hoping we'd have some video or at least sound samples for ya, but someone in our band forgot to charge their vid camera...   ::)
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: culturejam on August 15, 2010, 11:39:43 AM
I'm following the thread...yes yes.......I'm waiting for all "the dust to settle" and all the mods be sorted etc.

I'll be testing some mods over the next few days (just etched another PCB), so we should have at least a couple of verified, working mods pretty soon.

My first test will be to add a variable delay time control, a switch to go from 50/50 to "wetter" mix, and a feedback adjust switch. I doubt all that will fit in a 1590a, but you guys who work with those often surprise me.

More details to follow shortly.  :)
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Earthscum on August 15, 2010, 02:10:54 PM
... I doubt all that will fit in a 1590a, but you guys who work with those often surprise me.
...

No doubt!!! I wanna give it a shot with the 2 pot mods I'm using. I just added a 100k pot into the wet return to cut the signal out, which intensifies the effect. Actually, more of "Effect Intensity", then. The only other thing I did was took the 100R and tied it between the wiper and lug to ground of a 10k pot, and tied the other lug of the pot to pin 6. At max delay, the 10K is still a bit too much, but it helps increase the intensity of the effect for bass by delaying the lower frequencies enough to cause an audible shift. I'd suggest a 5k. At one side, you have straight 10k resistance, which you could just tailor with a resistor strapped across wiper to lug, and on the other end of rotation, you have the 10k with the 100R across it, so effectively just a little under. I did this on purpose so WHEN I build my GF's, I can just order one of the PCB's and use the mod instead of a resistor. Don't have to drill extra holes, which is kinda what I think modding a circuit like this is about... using what 'you got' (or the designer's layout) and doing what you can with it  ;)
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: culturejam on August 15, 2010, 02:47:01 PM
I'm populating the second board now. But I'm out of 220K resistors, so I'm going to try some different values and see what happens.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Renegadrian on August 15, 2010, 06:48:16 PM
...someone in our band forgot to charge their vid camera...   ::)

And that was the best performance ever...Classic... ;D
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Earthscum on August 15, 2010, 07:46:34 PM
I got showed up by our 'walk-in', Brooks, lol.

Actually, I forgot my fuzz and the extension cord... our guitarist, Fred, forgot to charge his camera, and our drummer AND Fred forgot the signal cables for the monitor amp up in Cheyenne. We pulled it off. It was a good show, blisters and all.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: culturejam on August 15, 2010, 09:03:32 PM
Testing is underway...

So far, 5K is definitely a good option for the Delay Time control. Too much more than that gives very noisy repeats. Unusably noisy.

One issue I'm having, however, is that on this build, if I hit notes pretty hard, I get some clipping/farty sounds. I've tried LF353 and 4558 for the op amp, and I've tried two different 2399 chips. Same result.

I've noticed, however, that the different op amps had different min/max LFO speeds. Interesting. The 4558 goes faster (with every other value in the LFO being the same). I'm out of NE5532.

I'm using a pair of 182K resistors in place of the pair of 220K in the LFO. That's the closest value I have.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Earthscum on August 15, 2010, 11:00:11 PM
Here's the mods I used last night. TI TL072BCP, Mylar Films on the .1uF's in audio path, ceramic for the others. Poly caps for the .01 & .001's. I may have used a ceramic across the inverting feedback on the LFO... it was acting strange. I'm gonna use a poly for that and see if it acts more normally next time I crack it open.

(http://www.aronnelson.com/gallery/main.php?g2_view=core.DownloadItem&g2_itemId=43552&g2_serialNumber=2)

1 - I changed the 470k pot to 100K. It gave me more useable range on the pot. This is probably due, as noted by culturejam, to the difference in OP Amps on the LFO... just a guess.

2 - The variable delay helped thicken up the low end with the extra shift in time... also adds a bit to the tricks you can get it to do!

3 - The "Wet Out" pot helps keep this out of flanging territory. I was getting too much wet signal and loosing the effect when the delay increased. This lets you drop the delayed signal a bit more into the background so you can still keep the nice chorusing effect. Also, within the usable (to you) range, you'll find a whole set of different tones available.

4 - The 10K on the output is just for trimming back the volume if you find, like with my setup, that the overtones really drive hard and throws your sound too far above everyone else when the pedal is engaged.

These pot mods use the existing (if you etch a PCB) resistor pads. You just solder the resistor between the center and outer lugs right on the pot. The output mod (referring to the layout http://i210.photobucket.com/albums/bb292/frequencycentral/LittleAngelPCB.gif (http://i210.photobucket.com/albums/bb292/frequencycentral/LittleAngelPCB.gif) ) you just cut the trace between the R14 pad and the C12/C15/OUT trace. If you drill a hole right next to the pad (to the right, under the right pads of C12 and C13), you can run a wire through from the top, fold it over and solder right to the R14 pad. Wire the other end to the output pad, run the output from your center lug and you're set!
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: my7of9 on August 16, 2010, 03:04:35 PM
.....and the PCB apparently will fit in a 1590A! This might well be my excuse to try my hand at a 1590A build. solderman? danielzink? valoosj?

I don't wish top be a party pooper but...
I have to report that I do not believe this will fit into a 1590A.
The board is exactly as wide as the outer dimensions of the enclosure. While you could perhaps lean the board I do not believe you would have room for the footswitch and especially jacks with a leaning board.

I will say it will fit a 1290 very nicely however.

If someone can prove me wrong...(Daniel Z. ?) .. I will certainly tip my hat to you!  :icon_biggrin:
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: culturejam on August 16, 2010, 05:30:39 PM
It took all damn day, but I figured out what was wrong with my second build. I had the wrong value caps connected to pins 9/10 and 11/12. I had 100pf when it should be 10nf. Whoops!

With 100pf there, hitting the strings hard caused a crackly-static sound. With 10nf, it's gone.

What exactly do those caps do? The pins on the data sheet are marked OP1 in and out (pins 9 and 10) and OP2 in and out (pins 11 and 12).
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Earthscum on August 16, 2010, 06:12:51 PM
That's one of the things I was asking about in this thread:  http://www.diystompboxes.com/smfforum/index.php?topic=86258.0 (http://www.diystompboxes.com/smfforum/index.php?topic=86258.0)

I think maybe it filters out the digital signal? I'm thinking about dropping some .015u's in place and see if it takes that bite off my sound on bass. ir maybe .022's. I definitely gotta swap some values in the input filter... again, I'm playing bass. I DEFINITELY don't have bass loss! At least not in the way that any signal is getting a noticeable bass cut. I actually have all the punch with the effect in, unlike other chorus' that seem to have some low end loss in the circuits. Simple IS good for Bass.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: culturejam on August 16, 2010, 06:24:09 PM
I think maybe it filters out the digital signal? I'm thinking about dropping some .015u's in place and see if it takes that bite off my sound on bass. ir maybe .022's.

The Princeton "data sheet" has one example circuit with 0.1uf in those spots. Hmmm.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: culturejam on August 16, 2010, 08:12:01 PM
With a 10K pot as the Delay Time control, only the last bit of the sweep introduces nasty noise in the wet signal. Bigger values (longer delay times) bring in a lot more noise.

So yeah, with a chorus-like modulation effect, the 5K DT pot works great. But I'm wondering now, as us DIY folks often do, if I up the value of the OPF1/2 caps from 10n to 47n or 100n...will that allow for cleaner longer delay times. Or maybe the HPF pin caps. I'm assuming that means "high-pass filter".

It really pisses me off that Princeton is so stingy with their info.  >:(
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: culturejam on August 16, 2010, 09:30:08 PM
Okay, here's the good data sheet:
http://www.princeton.com.tw/downloadprocess/downloadfile.asp?mydownload=PT2399_1.pdf

So apparently, the OP1/OP2 are internal op amps. And here's what the sheet says:

"OP amplifier 1 input/output. This pin can be used as modulated/Demodulated integrator by connecting capacitor
OP Amplifier 2 input/output. This pin can be used as Modulated/Demodulated Integrator by connecting Capacitor"

It would help if I understood what a "modulated/demodulated integrator" did.  :)

I'll probably just dick around with cap values and see what happens.  ;D
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Slade on August 16, 2010, 10:08:40 PM
Hey, I've retraced the PCB to tonepad's layout style and made a PDF with 6 ready to print boards.

Click on the image to download:

(http://img210.imageshack.us/img210/6448/littleangelchoruspcblay.jpg) (http://www.sendspace.com/file/hjpmd1)

Regards,
Fernando.-
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: joethugs on August 16, 2010, 10:26:03 PM
Thanks for this nice layout!
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: culturejam on August 16, 2010, 10:56:22 PM
Hey, I've retraced the PCB to tonepad's layout style

What software do you use for that style layout?

Thanks.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: joethugs on August 16, 2010, 11:16:51 PM
was also thinking about that?.. It's not DIY layout Creator? Right? ???
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Slade on August 16, 2010, 11:37:20 PM
It's made line by line and hole by hole with the only design program I use... Adobe Illustrator.

I shared this proyect in a chilean forum, and as it's a "beginner's" proyect I just made an easier-to-etch-PCB and an easy to build layout with the component values on the layout. Enjoy!
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: joethugs on August 16, 2010, 11:49:07 PM
no wonder your etching technique is superb because you design them in illustrator which is vector based as opposed to photoshop pixel based..
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Lurco on August 17, 2010, 04:03:45 AM
Okay, here's the good data sheet:
http://www.princeton.com.tw/downloadprocess/downloadfile.asp?mydownload=PT2399_1.pdf

So apparently, the OP1/OP2 are internal op amps. And here's what the sheet says:

"OP amplifier 1 input/output. This pin can be used as modulated/Demodulated integrator by connecting capacitor
OP Amplifier 2 input/output. This pin can be used as Modulated/Demodulated Integrator by connecting Capacitor"

It would help if I understood what a "modulated/demodulated integrator" did.  :)

I'll probably just dick around with cap values and see what happens.  ;D

It`s all about Delta Modulation http://en.wikipedia.org/wiki/Delta_modulation
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: earthtonesaudio on August 17, 2010, 08:40:42 AM
Okay, here's the good data sheet:
http://www.princeton.com.tw/downloadprocess/downloadfile.asp?mydownload=PT2399_1.pdf

So apparently, the OP1/OP2 are internal op amps. And here's what the sheet says:

"OP amplifier 1 input/output. This pin can be used as modulated/Demodulated integrator by connecting capacitor
OP Amplifier 2 input/output. This pin can be used as Modulated/Demodulated Integrator by connecting Capacitor"

It would help if I understood what a "modulated/demodulated integrator" did.  :)

I'll probably just dick around with cap values and see what happens.  ;D

It`s all about Delta Modulation http://en.wikipedia.org/wiki/Delta_modulation

I would say it's mostly about delta modulation, but there's some other fun stuff going on too.


The input signal goes through LPF1 and into the inverting comparator input and is converted to a 1-bit data stream.  This data then goes into OP1 through the box labeled "MOD" in the datasheet.  With the external capacitor, OP1 inverts and integrates this data and is fed back into the non-inverting input of the comparator, closing the loop of the delta modulator.  With too small of a cap, the differential signal at the comparator is very small, so it has a hard time saying whether the input signal is higher or lower than the reference, and the result is drastically reduced gain, except at very high slew rates, where the too-small cap is just barely sufficient to let some signal through.

Because this integrator is part of an overall negative feedback loop, making its capacitor larger reduces the integrator's gain (starting at high frequencies) but increases the gain of the A-D stage as a whole.


Finally, another area of interest is the "MOD" section, which I believe to be a SPDT switch.  The pole connects to pin 8 and so the circuit becomes a switched-capacitor resistor of approximate value R=1/(fC), where f is the clock frequency and C is the capacitor from pin 8 to ground.  So when the clock frequency decreases, the resistor going into the integrator increases, and the integrator's cutoff frequency decreases.  Again, because this occurs in a negative feedback loop, the overall effect is the opposite, such that a decreased clock frequency results in pre-emphasis of treble at the A-D stage.  Meanwhile, the output after the delay goes into OP2, which is similarly modulated by the clock, but here the decrease in clock frequency causes a treble cut, which helps you get away with lower fidelity at longer delay times.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: culturejam on August 17, 2010, 10:18:24 AM
Because this integrator is part of an overall negative feedback loop, making its capacitor larger reduces the integrator's gain (starting at high frequencies) but increases the gain of the A-D stage as a whole.

Right. So I'll start dicking around with cap values here and see what happens.  :D


Quote from: earthtonesaudio
Finally, another area of interest is the "MOD" section, which I believe to be a SPDT switch.  The pole connects to pin 8 and so the circuit becomes a switched-capacitor resistor of approximate value R=1/(fC), where f is the clock frequency and C is the capacitor from pin 8 to ground.  So when the clock frequency decreases, the resistor going into the integrator increases, and the integrator's cutoff frequency decreases.  Again, because this occurs in a negative feedback loop, the overall effect is the opposite, such that a decreased clock frequency results in pre-emphasis of treble at the A-D stage.  Meanwhile, the output after the delay goes into OP2, which is similarly modulated by the clock, but here the decrease in clock frequency causes a treble cut, which helps you get away with lower fidelity at longer delay times.

I'll pop the hood on my Echobox, as I recall Brian from Subdecay mentioned something about how it was filtered. It gets about 1 second of relatively clean delay, which is insane considering the THD on this chip at that delay time.

I assume the DEM section is "demodulator". The data sheet calls pin 7 (DEM) and pin 8 (MOD) "Current Control" 1 and 0, respectively. And both application circuits have a 100n cap to ground from these pins. Again, I'll have to just goof off with changing cap values and see if I can hear anything.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: jimmybjj on August 17, 2010, 10:37:34 AM
no wonder your etching technique is superb because you design them in illustrator which is vector based as opposed to photoshop pixel based..
sorry for the OT but does this make a difference?
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: slacker on August 17, 2010, 12:59:25 PM
It`s all about Delta Modulation http://en.wikipedia.org/wiki/Delta_modulation

Thanks for the link, the datasheet block diagram finally makes sense to me :)
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Perrow on August 17, 2010, 07:07:55 PM
I just love watching a new pedal be born  ;D
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: p_wats on August 23, 2010, 04:14:01 PM
Hey guys, I tried a perf/p-to-p layout for this, but it's only my second time ever going from schematic to layout, so I screwed up somewhere and I get nothing but a faint hum. Can anyone see anything glaringly wrong at a glance?

(http://www.facekick.ca/images/littleangel_layout.jpg)
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: culturejam on August 23, 2010, 06:12:35 PM
Pins 3 and 4 should be grounded, not just connected to each other.

Pin 4 is the analog ground, and if it ain't grounded, you don't get sound.   :icon_mrgreen:
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: p_wats on August 23, 2010, 06:25:33 PM
Pins 3 and 4 should be grounded, not just connected to each other.

Pin 4 is the analog ground, and if it ain't grounded, you don't get sound.   :icon_mrgreen:

Thanks for the catch. That's just a drawing error though, as I actually did ground pin 4 when I perfed it...so there's probably something else keeping it from working.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: culturejam on August 23, 2010, 07:12:14 PM
I think I see the problem.

The 470K resistor should connect directly to pin 6 of the op amp. You have it connected to pin 7.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: JKowalski on August 23, 2010, 07:41:16 PM
no wonder your etching technique is superb because you design them in illustrator which is vector based as opposed to photoshop pixel based..

Photoshop does vectors too! Even on my now-very-old photoshop 7 that can't install on windows 7.  :'(
Title: "Little Angel" Mini Chorus 1590A Layout
Post by: frequencycentral on August 26, 2010, 03:05:35 AM
.....and the PCB apparently will fit in a 1590A! This might well be my excuse to try my hand at a 1590A build. solderman? danielzink? valoosj?

I don't wish top be a party pooper but...
I have to report that I do not believe this will fit into a 1590A.
The board is exactly as wide as the outer dimensions of the enclosure. While you could perhaps lean the board I do not believe you would have room for the footswitch and especially jacks with a leaning board.

I will say it will fit a 1290 very nicely however.

If someone can prove me wrong...(Daniel Z. ?) .. I will certainly tip my hat to you!  :icon_biggrin:

 :o Shock and disappointment! So I've shaved it down to fit. I believe a board 13 pads wide will fit in a 1590A. The only compromise it that the connection for Depth pot lug 3  has moved from the edge of the board to, err, elsewhere. If anyone wants to etch one for me.......... :)

(http://i210.photobucket.com/albums/bb292/frequencycentral/LAC1590APCB.gif)
(http://i210.photobucket.com/albums/bb292/frequencycentral/LAC1590APnP.gif)
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Pigyboy on August 26, 2010, 03:50:38 AM
Wow. Great work Rick.
 Has any one tried this with a bass yet?
 My friend Dan McNay is playing with Ronnie Montrose and The Frank Hannon Band and asked me yesterday of an interesting bass chorus. Any cap replacements to make it more bass friendly would be great.
 Rick, do you mind if I use the layout to make him one?  I will get pictures for you.
Thanks
Title: Re: "Little Angel" Mini Chorus 1590A Layout
Post by: Pigyboy on August 26, 2010, 04:03:23 AM

[/quote]
If anyone wants to etch one for me.......... :)
[/quote]

I can etch a few of these and send you one next week no problem.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: frequencycentral on August 26, 2010, 04:03:54 AM
Has any one tried this with a bass yet?

Earthscum has used it with bass and seems to like it!

Rick, do you mind if I use the layout to make him one?  I will get pictures for you.

That's what it's here for!

I can etch a few of these and send you one next week no problem.

 :icon_biggrin:

I just tweaked that layout slightly so C8, C9 and C10 can be bent over to lay flat if need be, it will show up in my post above when photobucket gets it's shit together to finally refresh.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Govmnt_Lacky on August 26, 2010, 08:24:06 AM
This may be a noob question but...

If I copy the layout from Frequency above, are there any special changes I need to make in order to "size it right?" Or, is it already properly sized to populate with components?
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: frequencycentral on August 26, 2010, 08:33:49 AM
This may be a noob question but...

If I copy the layout from Frequency above, are there any special changes I need to make in order to "size it right?" Or, is it already properly sized to populate with components?

Scale the PnP to a .1 inch grid in photoshop. An ICs pin spacing will match the grid when correctly sized. Is that what you mean?

-------------------------------------------------------------------------------------------------------------------------------------------------------------------

I see my 'slightly tweaked' 1590A layout in my last post still hasn't refreshed in photoshop, so here's direct links in dropbox:

http://dl.dropbox.com/u/967492/LAC%201590A%20PCB.gif

http://dl.dropbox.com/u/967492/LAC%201590A%20PnP.gif
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: culturejam on August 26, 2010, 08:49:33 AM
Here's a little layout note:

C11 is really close to D1 (which must be mounted vertically) and R19. So it either needs to be a smallish cap, or leave some slack on the leads so you can bend it over and lay it flat over R19.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: frequencycentral on August 26, 2010, 08:54:15 AM
Yeah, there's not much room there (sorry!), I didn't want to make the layout bigger just for the sake of one pesky diode. I figured people might instead mount the diode on the copper side or even directly to the DC socket. This would also allow C11 to be bent over on it's side for extra 1590A squeezage. That's what I'll gonna do.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: culturejam on August 26, 2010, 09:10:29 AM
By the way, Rick, I've played around with several values of resistors where the two 220Ks are located. I ran out of 220K, so I took the opportunity to socket those spots and test it out. I can say for sure that any value between 150K and 275K will work in either or both of those positions. Waveform and min/max speed will change, of course, but several alternative values will work in a pinch.

Also, different op amps make a subtle, but noticeable, change in the LFO waveform shape.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Govmnt_Lacky on August 26, 2010, 09:28:46 AM

Scale the PnP to a .1 inch grid in photoshop. An ICs pin spacing will match the grid when correctly sized. Is that what you mean?


I do not have Photoshop. Any other way to ensure it prints out to correct size?
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: nordine on August 26, 2010, 10:08:00 AM

Scale the PnP to a .1 inch grid in photoshop. An ICs pin spacing will match the grid when correctly sized. Is that what you mean?


I do not have Photoshop. Any other way to ensure it prints out to correct size?

the hard way: trial and error  ;D

i print three tries with marginally different sizes, then pick an IC socket and see on which one it fits better
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: frequencycentral on August 26, 2010, 10:14:49 AM

Scale the PnP to a .1 inch grid in photoshop. An ICs pin spacing will match the grid when correctly sized. Is that what you mean?


I do not have Photoshop. Any other way to ensure it prints out to correct size?

You can also do it in MS Publisher, I just tested it. I made a grid 0.254mm (= 0.1") and scaled the pad spacings to that. Worked a treat.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Govmnt_Lacky on August 26, 2010, 10:29:19 AM

Scale the PnP to a .1 inch grid in photoshop. An ICs pin spacing will match the grid when correctly sized. Is that what you mean?


I do not have Photoshop. Any other way to ensure it prints out to correct size?

You can also do it in MS Publisher, I just tested it. I made a grid 0.254mm (= 0.1") and scaled the pad spacings to that. Worked a treat.

I also do not have MS Publisher. As you can tell from my login, I work for the government. They do not give us cool software tools like MS Publisher. Any other ideas? Sorry to be a pain. Can anyone tell me a % to shrink this down to in order to get the sizes correct?
Any other ideas would be appreciated.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Govmnt_Lacky on August 26, 2010, 10:35:39 AM

You can also do it in MS Publisher, I just tested it. I made a grid 0.254mm (= 0.1") and scaled the pad spacings to that. Worked a treat.

Sorry about my first reply.... Here goes again...

I also do not have MS Publisher. As you can tell from my login, I work for the government. They do not give us cool software tools like MS Publisher. Any other ideas? Sorry to be a pain. Can anyone tell me a % to shrink this down to in order to get the sizes correct?
Any other ideas would be appreciated.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: radio on August 26, 2010, 11:04:18 AM
Hi

I m at work too(but in Central Europe). I just "open with" PAINT , did a "resize" to 50%.

I printed out and mesured,seems to be ok with 2.54 mm distance from hole to hole.

Regards Jean-Marie

Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: frequencycentral on August 26, 2010, 11:12:07 AM
(http://i210.photobucket.com/albums/bb292/frequencycentral/6.jpg)
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Govmnt_Lacky on August 26, 2010, 11:58:31 AM
Hi

I m at work too(but in Central Europe). I just "open with" PAINT , did a "resize" to 50%.

I printed out and mesured,seems to be ok with 2.54 mm distance from hole to hole.

Regards Jean-Marie



Jean-Marie,

Thanks. I took your advice and used Paint. I resized to about 47% and it works great.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Govmnt_Lacky on August 26, 2010, 02:28:55 PM
I appreciate everyones help and I can't wait to get started on this little beauty. I have one more question:

Are there any FINAL decisions on the size of the Speed and Depth pots? I have read through the thread but I still do not see any definitive values yet.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: frequencycentral on August 26, 2010, 02:36:02 PM
AFAIC it's 100k lin for Speed and 470k lin for Depth. That's how I liked it. Purrrrrrrr......
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Pigyboy on August 27, 2010, 01:37:10 AM
Hi Rick,
How about running this at 12-18v for more headroom like the Analogman Chorus?
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: markeebee on August 27, 2010, 02:14:11 AM
Sorry, Rick is unable to answer. He's too busy scratching the furniture and licking his bum.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Pigyboy on August 27, 2010, 05:13:56 AM
Sorry, Rick is unable to answer. He's too busy scratching the furniture and licking his bum.

Dude, that is funny.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: anchovie on August 27, 2010, 05:19:59 AM
Hi Rick,
How about running this at 12-18v for more headroom like the Analogman Chorus?

It won't give you any more headroom in the PT2399 as that's running off regulated 5V regardless.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Pigyboy on August 27, 2010, 05:30:03 AM
Hi Rick,
How about running this at 12-18v for more headroom like the Analogman Chorus?

It won't give you any more headroom in the PT2399 as that's running off regulated 5V regardless.
Hmm,  That is what I was afraid of. Can anyone who has built this give it a go really loud though a bass set up and report if it loses much in the low end.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: culturejam on August 29, 2010, 03:33:58 PM
Can anyone who has built this give it a go really loud though a bass set up and report if it loses much in the low end.

Someone earlier in the thread used it with bass and commented on the low end response. Start reading on page 4/5 and you should eventually find it.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Earthscum on August 29, 2010, 08:52:43 PM
Aye. I've used it at 2 shows. For bass, you want to increase the delay a little bit for sure. I like the 5k pot, but already had the 10k installed.

For bass, once you find that perfect setting for you, you go from flat to gigantic godly overtones!

I used a TL072, hence the 100k pot in place of the 470k. I haven't un-ductaped my pedal to pop in an NE yet, so can't report on that. I rode my bike to the store to buy parts, came home and had it boxed and working and ready in 5 hours, with only an hour to spare before we had to be at the bar. Used it in an outdoor setting at the last one, and it is awesome. If you are outdoors, you can increase the depth a bit more without busting through over the top of the guitars.

And, lastly... absolutely no bass cut! I breadboarded mine with .022's in the audio paths, but I built it with all stock parts plus my mods to box up. I have a "super-fat" DS-1 that is basically my big OD. It increases the bass without destroying too much of the punch, still has the DS-1 grit, but bigger. This goes in front of my LA, and I only get the most minor bass cut out of it, which actually just seems to add to the overall tonal qualities.

Of all the things I tried, the ONLY one necessary for bass is the delay mod. Just a 5k pot. I wired mine so I could (next build) use the stock jumper pads from the layout. I just used a DIP strip on this one, but kept mods simple to work with the stock PCB.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Pigyboy on August 30, 2010, 03:27:06 AM
Thanks for the info Earthscum. I am gonna make some boards today and give it a go. This one is going to friend who is playing to 1000-5000 people a night so we will how the Angel does on a big stage. I have a good feeling about it.
Thanks again and a big thanks to Rick
I will report back soon but I still need to order parts :P
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Valoosj on August 30, 2010, 08:18:20 AM
.....and the PCB apparently will fit in a 1590A! This might well be my excuse to try my hand at a 1590A build. solderman? danielzink? valoosj?

Seems I noticed this a bit late, but I might still make a layout, once the dust settles, as Dan said.

My first test will be to add a variable delay time control, a switch to go from 50/50 to "wetter" mix, and a feedback adjust switch. I doubt all that will fit in a 1590a, but you guys who work with those often surprise me.


I think we even surprise ourselves at times, when finally cramming something in a very tight enclosure.

Oh btw Rick, the flanger pcb will probably be made in the following weeks, since the workload for my studies will not be so huge in the following 3 weeks, so I might be able to make some pedals as well! But first I need to make some layouts and etch the suckers.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: p_wats on August 30, 2010, 10:29:19 AM
Hmm, I also used a TL072 in my perf attempt without changing any other components. Could that be contributing to my lack of effect?
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Govmnt_Lacky on August 30, 2010, 10:34:41 AM
Sounds like resolution is needed on the great Little Angel Op amp/potentiometer debate....

Will it be the TL072 with a 100K or.... the 5532 with the 470/500K????

The debate rages on... ::)
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: earthtonesaudio on August 30, 2010, 12:26:10 PM
I don't see any reason to prefer the NE5532 in this circuit, other than the fact that it's already been verified.  However, if you do want to swap op-amps, the input resistance of the NE5532 is so low that a TL072 is not really a direct replacement.  You'll need to reduce the gain of the audio part and mess with the impedances in the LFO part to make the performance the same with a TL072.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: waltk on August 30, 2010, 12:34:38 PM
Here's my "Little Blue Angel".  Worked the first time (with no debugging).  No parts substitutions.  Sounds great.
Thanks Rick!

(http://www.aronnelson.com/gallery/main.php?g2_view=core.DownloadItem&g2_itemId=43589&g2_serialNumber=2)
Title: "Little Blue Angel"
Post by: frequencycentral on August 30, 2010, 01:00:41 PM
^^^^  :icon_biggrin:

Hey that's the 1590A layout! You gonna squeeze it in?  ;)

Of course we want photos and soundclips.......
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: waltk on August 30, 2010, 01:06:24 PM
Quote
Hey that's the 1590A layout! You gonna squeeze it in?

Don't have a 1590A box at the moment, but I do have another smallish box that should be a nice snug fit.  Pictures to follow later...

Rick - I etched some extra boards.  PM me with your mailing address if you want one.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: culturejam on August 30, 2010, 05:04:16 PM
Sounds like resolution is needed on the great Little Angel Op amp/potentiometer debate....

Will it be the TL072 with a 100K or.... the 5532 with the 470/500K????

I've tried different op amps, and it does change the shape of the waveform slightly from chip to chip. So it will be a personal choice, I think.

Haven't tried the 100K pot.


Here's my "Little Blue Angel".  Worked the first time (with no debugging).  No parts substitutions.

Nice looking work, Walt!
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Brymus on September 01, 2010, 07:44:57 PM
Has there been a list of proven mods made yet ?
I am about to BB this,I was hoping some tweaks would have been added by now.
Is there a Deluxe Angel yet or is it still the Little Angel ?
Been off the net for a week or so,so I havent been keeping up  :icon_redface:
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: frequencycentral on September 01, 2010, 07:51:45 PM
Is there a Deluxe Angel yet or is it still the Little Angel ?

"Archangel" is around a month or so away. Let me clear my bench..... ;D
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Brymus on September 01, 2010, 08:08:01 PM
Is there a Deluxe Angel yet or is it still the Little Angel ?

"Archangel" is around a month or so away. Let me clear my bench..... ;D
sweetness !!!
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: joethugs on September 01, 2010, 09:21:50 PM
damn! i'll be waiting for that... Archangel! :icon_twisted:
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: waltk on September 01, 2010, 11:57:27 PM
Quote
Of course we want photos and soundclips.......

I did a little rework to make my board a little shorter.  It's in the box (which is still undecorated) with all the standard gear - led, power jack, etc.  Not quite as small as a 1590A, but still fairly compact.  The PT3299 draws a bit of current, so I expect the power jack will be a necessity.  The depth pot (B500K for mine) is only useful in the top 20% of the range, so I'll need to tweak something to give a better range (suggestions?)

(http://www.aronnelson.com/gallery/main.php?g2_view=core.DownloadItem&g2_itemId=43644&g2_serialNumber=2)

(http://www.aronnelson.com/gallery/main.php?g2_view=core.DownloadItem&g2_itemId=43641&g2_serialNumber=2)
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Govmnt_Lacky on September 02, 2010, 08:57:53 AM
The depth pot (B500K for mine) is only useful in the top 20% of the range, so I'll need to tweak something to give a better range (suggestions?)


Have you tried a C500K? Maybe that will give you more usable range.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: waltk on September 02, 2010, 09:11:37 AM
Quote
Have you tried a C500K? Maybe that will give you more usable range.

Thanks for the suggestion.  I don't have any reverse audio taper pots on hand, but was thinking I could just reduce the pot value to B100K - that would be equivalent to the top 20% of the 500K pot.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Govmnt_Lacky on September 02, 2010, 09:35:07 AM
Sorry... I must have been mistaken. I thought you meant the top 20% of your pot to be the top 20% of the resistance being from 400-500K. Using a Reverse Audio pot would have "smoothed out" that last 100K of resistance over a larger part of the pot rotation.

Did you mean to say that you only get use of the INITIAL 20% of the pot rotation?
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: waltk on September 02, 2010, 12:44:40 PM
Quote
Did you mean to say that you only get use of the INITIAL 20% of the pot rotation?

Nope.  The last 20% of clockwise rotation is the useful bit.  Remember, the pot is only wired with lugs 2 and 3 (its a stright variable resistor), so as you turn the pot clockwise, the resistance falls to 0.  So if you replace the 500K pot with a 100K pot, the full rotation would have exactly the same effect as the last 20% of the 500K pot.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: frequencycentral on September 02, 2010, 12:50:09 PM
Thanks to Pigyboy! Haven't had chance to hook it up yet, and I've only just ordered the 1590A.......

(http://i210.photobucket.com/albums/bb292/frequencycentral/AngelBoard.jpg)
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Govmnt_Lacky on September 02, 2010, 01:01:43 PM
Nope.  The last 20% of clockwise rotation is the useful bit.  Remember, the pot is only wired with lugs 2 and 3 (its a stright variable resistor), so as you turn the pot clockwise, the resistance falls to 0.  So if you replace the 500K pot with a 100K pot, the full rotation would have exactly the same effect as the last 20% of the 500K pot.

Thanks for the clarification.  ;D
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: clamup1 on September 02, 2010, 02:08:32 PM
hey two things:
1. i put both ics in backward. is one or both fried.
2. do you ground the jacks to each other and then ground to the box.

this was the biggest solder job to date. thanks its was a blast

Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Govmnt_Lacky on September 02, 2010, 02:20:28 PM
hey two things:
1. i put both ics in backward. is one or both fried.
2. do you ground the jacks to each other and then ground to the box.

this was the biggest solder job to date. thanks its was a blast



Hey...two responses..

1) May be... May not be. Odds are that they are OK but only a voltage/operational check will know for sure.
2) You can ground everything however you like as long as you ground everything that needs grounding and have NO ground loops. Remember to ground the SLEEVES of the jacks to each other (and to the other grounds). Refer to JD's site GGG as a resource. I use it religiously for offboard wiring.

Good Luck!
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: frequencycentral on September 02, 2010, 02:21:35 PM
1. i put both ics in backward. is one or both fried.

The dual opamp is fried. The PT2399 probably survived.


2. do you ground the jacks to each other and then ground to the box.

Yup, and to the DC socket's ground. And to the board's ground: http://www.beavisaudio.com/techpages/StompboxWiring/
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Electron Tornado on September 02, 2010, 02:53:04 PM
Here's my "Little Blue Angel".  Worked the first time (with no debugging).  No parts substitutions.  Sounds great.
Thanks Rick!

(http://www.aronnelson.com/gallery/main.php?g2_view=core.DownloadItem&g2_itemId=43589&g2_serialNumber=2)


Where did you find the blue PCB material?
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: clamup1 on September 02, 2010, 09:33:21 PM
i hope the op amp isnt fried. if i test it and put some numbers up can you guys tell me if its fried? or am i not going to get anything if its fried? i have a 3pdt in another pedal i might steal and use the schems you guys recomend. thanks for the help
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Pigyboy on September 03, 2010, 04:55:54 AM
Thanks to Pigyboy! Haven't had chance to hook it up yet, and I've only just ordered the 1590A.......

(http://i210.photobucket.com/albums/bb292/frequencycentral/AngelBoard.jpg)
Looks nice Rick. Glad to help out.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: frequencycentral on September 03, 2010, 04:59:25 AM
Thanks to Pigyboy! Haven't had chance to hook it up yet, and I've only just ordered the 1590A.......

Looks nice Rick. Glad to help out.


I'll hook it to the breadboard for testing it later this morning, thanks again.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: frequencycentral on September 03, 2010, 05:49:30 AM
Re. Depth pot value debate:

The more minimum settings shouldn't be dismissed out of hand. Take away (most of) the modulation and you've got automatic double tracking, which we don't seem to talk about much around here. ADT has the effect of thickening the sound as if two people were playing the same part in unison. You might not notice the thickening until you bypass it - then your sound will seem thin and weedy by comparison!  :D  Process your vocalist through the Little Angel at minimum settings - he/she/it will love you forever.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: slacker on September 03, 2010, 11:55:29 AM
i hope the op amp isnt fried.

Unfortunately, if you connected it backwards, then it's dead.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Govmnt_Lacky on September 03, 2010, 12:08:23 PM
I dont know if it is particular to this circuit however, I have put Op Amps in backwards and they have survived in most situations..... Actually 1 situation since it has only happened twice! So I guess you have a 50/50 shot.

Good Luck!  ;D
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: clamup1 on September 03, 2010, 03:07:27 PM
numbers

1-8.1
2-8.37
3-8.75
4-8.75
5-8.29
6-8.26
7-8.26
8-8.80

this is with the battery in and on the neg side.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Govmnt_Lacky on September 03, 2010, 06:05:57 PM
Uhhhhhh.... Hate to say it but. THAT BAD BOY IS FRIED!!!

That is unless you ran supply power to EVERY pin. You should have Input power on pin 8 and Ground on pin 4.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: clamup1 on September 03, 2010, 11:18:25 PM
i was wondering why i had power on all the pins. damn. oh well i got more coming. i was hoping i would get this one to work first time
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: waltk on September 04, 2010, 12:16:56 AM
Quote
oh well i got more coming.

5532 opamps are highly recommended (a little low on the input impedance, but a great driver on output).  Not to start a debate or anything, but between these and TL072 you are pretty well covered for anything you would want to build.  Someone is selling 50 5532's on Ebay for 10.99 (including shipping) at the moment.  If you plan to continue building DIY stompboxes, I would just order a nice supply.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: clamup1 on September 04, 2010, 09:19:58 AM
i ordered some from small bear yesterday. i should of checked out ebay. thanks for the info. ill check them next go round
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: John Lyons on September 04, 2010, 09:50:37 AM
Quote
oh well i got more coming.
  Someone is selling 50 5532's on Ebay for 10.99 (including shipping) at the moment. 

Thanks for the tip. I got 50 and some caps as well.
50ish pages of non sorted items later... ::)
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Pigyboy on September 04, 2010, 10:32:44 AM
Hmm, I can only find a link for 50 x 5532's for $14.95 + 5 shipping on ebay. 

Will 5534's work as well? Is it much difference between the 5532 and the 5534?
I have a bunch of the 34's but no 32's.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: John Lyons on September 04, 2010, 10:54:33 PM
A 5534 is a single op amp. A 5532 is a dual.

This is the only current auction the guy has for 5532s now.
Still a good deal.
http://cgi.ebay.com/Lot-50-NE5532-NE5532P-5532-Dual-Low-Noise-OP-Amp-/220664349135?pt=LH_DefaultDomain_0&hash=item33609ec1cf (http://cgi.ebay.com/Lot-50-NE5532-NE5532P-5532-Dual-Low-Noise-OP-Amp-/220664349135?pt=LH_DefaultDomain_0&hash=item33609ec1cf)
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Earthscum on September 04, 2010, 11:02:25 PM
That's not bad. That comes out to 28 cents apiece. Tayda has them for 32 cents each, if you don't need 50. For $14.60 (after shipping) you still get 40. That's not bad, either.

http://www.taydaelectronics.com/servlet/the-93/5532-DUAL-INSTRUMENTS-LOW/Detail (http://www.taydaelectronics.com/servlet/the-93/5532-DUAL-INSTRUMENTS-LOW/Detail)
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: clamup1 on September 06, 2010, 05:00:55 PM
oh i used a 3904 as the tranie. i read it could be used but didnt look to see if anything else had to be changed. will it work when i get the new chip or ar there other things that need to be changed?
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: frequencycentral on September 06, 2010, 05:05:51 PM
oh i used a 3904 as the tranie. i read it could be used but didnt look to see if anything else had to be changed. will it work when i get the new chip or ar there other things that need to be changed?

The 3904 is a NPN transistor. The 'tranny' in this circuit is not a 'tranny', it's a 5v voltage regulator.

Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: culturejam on September 06, 2010, 06:23:06 PM
oh i used a 3904 as the tranie. i read it could be used...

Where did you read that?
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Earthscum on September 06, 2010, 07:31:20 PM
oh i used a 3904 as the tranie. i read it could be used but didnt look to see if anything else had to be changed. will it work when i get the new chip or ar there other things that need to be changed?

This doesn't use a transistor as the controlling element for the LFO like the designs for other PT delays use. This has 2 chips, a 5V regulator, and a handful of Resistors and caps (and whatever else you want to mod it with). The LFO connects directly to the chip.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: clamup1 on September 07, 2010, 03:53:26 AM
i thought i read it in there somewhere oh well. now i need to beg the wife for more money.  :icon_redface:
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Taylor on September 07, 2010, 04:12:12 AM
That is indeed an unfortunate tranny surprise.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Pigyboy on September 07, 2010, 06:59:27 AM
That is indeed an unfortunate tranny surprise.
Had a 'Trannie' surprise in a bathroom in SF one night. Indeed, unfortunate.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: clamup1 on September 10, 2010, 03:53:52 PM
hey does the words on the LFO go toward the ic or away from it.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: clamup1 on September 10, 2010, 04:17:58 PM


(http://www.aronnelson.com/gallery/main.php?g2_view=core.DownloadItem&g2_itemId=43589&g2_serialNumber=2)
[/quote]

sorry i found the pic

i get clean sound. no chorus. its prob the offboard wiring. i hate offboard wiring
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Güero on September 10, 2010, 06:45:53 PM
(http://www.aronnelson.com/gallery/main.php?g2_view=core.DownloadItem&g2_itemId=43589&g2_serialNumber=2)
i get clean sound. no chorus. its prob the offboard wiring. i hate offboard wiring
[/quote]






I think that 7805 regulator is inverted...

Try the actual orientation

Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: blooze_man on September 10, 2010, 07:06:00 PM
I wonder how this would sound if it had a tone control
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: clamup1 on September 10, 2010, 10:56:37 PM
hey does the words on the LFO go toward the ic or away from it.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Taylor on September 10, 2010, 11:31:07 PM
An LFO is not a part, it's a circuit with a number of parts that make it up. So what are you referring to when you say "LFO"? Are you talking about the thing with 3 legs and a metal tab on it? That is called a regulator, and you appear to have it in right.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: clamup1 on September 11, 2010, 08:27:33 AM
thats not my pic but i put it in that way. thanks
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: frequencycentral on September 11, 2010, 08:47:26 AM
I wonder how this would sound if it had a tone control

I'm gonna add a 'dark' pot for tone to the elite version - "Archangel"

@ clamup1: did you use a NE5532 dual opamp? The circuit values are set up to work with a NE5532. Other dual opamp type will give different results.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: clamup1 on September 12, 2010, 12:45:42 PM
@ clamup1: did you use a NE5532 dual opamp? The circuit values are set up to work with a NE5532. Other dual opamp type will give different results.

yeah i used the 5532. i got everything in and its still didnt work. i get clean but no effect. ive seen 2 different ways to hook up 3pdt and cant get either one to work.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: frequencycentral on September 12, 2010, 01:13:39 PM
i get clean but no effect. ive seen 2 different ways to hook up 3pdt and cant get either one to work.

Can you test the circuit away from the 3pdt? It may be your 2pdt wiring that's causing the problem. Maybe.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: clamup1 on September 12, 2010, 02:49:48 PM
my chips are facing the right way and i still have 8.29 on the ground. i had to buy a new solldering iron b/c the tip dissengrated so i was leaving huge solder bumps on the board. i think i have to either reetch a board or desolder and try again
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Earthscum on September 12, 2010, 02:53:46 PM
clam: quick question... did you socket the IC's? If so, have you tried just swapping out IC's? There was a bad batch of (possibly counterfeit) PT's running around. I'm pretty sure that the normal DIY pedalbuilder sources are fine, I don't remember Steve or anyone saying that they came from their batches.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: frequencycentral on September 12, 2010, 03:03:17 PM
my chips are facing the right way and i still have 8.29 on the ground.

Look for solder bridges anywhere where the (red) +9v trace is close to the (brown) ground trace. ie around C11, D1, R8, R9.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Earthscum on September 12, 2010, 03:26:22 PM
Should we Keen clam and refer him to This Page (http://www.diystompboxes.com/smfforum/index.php?topic=29816.0)?  :icon_twisted:

I blew out a TL072 and got a short through the chip. I kept getting my 9V on the ground, regular VR's where they were supposed to be. I about fried my PS, and probably would have if I didn't catch the smoke from melting plastic... heat sinks are GOOD!
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: clamup1 on September 12, 2010, 06:09:12 PM
both ic's are in sockets. i have swapped both ic's. i got my ic's from small bear i dont think they would sell bad chips. ill check for solder bridges, it wouldnt surprise me
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: clamup1 on September 12, 2010, 07:17:48 PM
hey i think i fgured it out. the diode is blown or not hooked up right. im getting 8.72 on the neg side of the diode. which accounts for why i have 8.72 on the ground. i didnt know you could blow diodes. i hope this works. ive been staring at this thing for an hour.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: clamup1 on September 12, 2010, 07:38:32 PM
well that didnt work. im getting almost the same mv thats coming off the end of the diode. i dont know what it is. i gotta study for a test. later
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: frequencycentral on September 12, 2010, 08:02:13 PM
well that didnt work. im getting almost the same mv thats coming off the end of the diode. i dont know what it is. i gotta study for a test. later

Is the diode correctly oriented?
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: soggybag on September 12, 2010, 11:53:51 PM
I just built one of these for myself, from the layout here. I used a piece of perfboard, but followed the PCB layout.

Before adding any ICs I powered everything up and tested the voltage at the correct pins. Op-amp pin 8, 5V at the regulator and PT2399. Everything checked out. When I put the chips in I wasn't getting any oscillation. After a long "close" inspection I couldn't figure it out. Came back later for a quick look and see an obvious solder bridge. Fixed that and everything started working. Never under estimate the effect of taking a break on your productivity.

I haven't given it much of a test yet. First impressions seem to say that everything is working correctly. Sounds to me like the LFO has sort of a wobble to it. Like it's not quite a triangle. This seems to change as the speed and depth are adjusted. I'll have to test it some more.

I did sub the 100 ohm resistor from PT2399 Pin 6 to ground with 82 ohm, as this was the closest I had on hand. I figure this wouldn't make much difference? I'm thinking about adding 50K pot to ground at this resistor to get regular delay and chorusy sounds. I assume this should work.

Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Earthscum on September 13, 2010, 12:12:04 AM
I'm starting to wonder if C11 (power filter cap) isn't bad? What typically happens to caps when they go bad?

I've had a cap that I suspected was blown and it read as a resistive short (aluminum electrolytic), but I don't know if that is typical behavior... I threw it away without an autopsy, but I'm guessing the dielectric  material melted and allowed the 'plates' to make contact.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: clamup1 on September 13, 2010, 08:10:26 AM
i have gone over the + rail and scraped all the melted plastic away from everything else. the diode is put in the same way as its in on the schem. i didnt check the cap. i did break both of my small drill bits so i had to use a 1/16 on the end where the pot, +,-, wires go. soldering those was fun. i also unhooked the switch and took out the ic's.   
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: clamup1 on September 13, 2010, 10:51:20 AM
 :icon_redface: im not gonna tell you what i did wrong but i got that fixed

now i get clean with ossilation, switch on have to turn my amp all the way up and only get a little bit of signal.

Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: clamup1 on September 13, 2010, 04:28:23 PM
i have a ? about how to hook up the jacks. im not at my home computer so i cant find the website but. does the board have to be grounded to the encloser and do the jacks have to be grounded to each other.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: frequencycentral on September 13, 2010, 06:05:30 PM
does the board have to be grounded to the encloser and do the jacks have to be grounded to each other.

Yes!
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: BoxOfSnoo on September 14, 2010, 08:33:00 AM
does the board have to be grounded to the encloser and do the jacks have to be grounded to each other.

Yes!

And furthermore, Yes! (http://www.beavisaudio.com/techpages/StompboxWiring/)
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: clamup1 on September 14, 2010, 01:19:48 PM
i had really cool star trek sound effects then it quit. i dont think i have this thing wired right. i have it wired like this

http://www.diystompboxes.com/smfforum/index.php?topic=970.0
no led 
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: clamup1 on September 14, 2010, 02:21:57 PM
aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: YouAre on September 22, 2010, 01:01:53 PM
Did anyone uh....replace the 100r resistor at pin 6 (or whichever is the delay time pin, totally forgot) with an LDR that's controlled by the same LFO or another lfo? Cause that could make for a pretty sweet flanger.....right?
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: frequencycentral on September 22, 2010, 02:39:12 PM
Did anyone uh....replace the 100r resistor at pin 6 (or whichever is the delay time pin, totally forgot) with an LDR that's controlled by the same LFO or another lfo? Cause that could make for a pretty sweet flanger.....right?

Replacing the 100R with a LDR would increase the delay time of the PT2399 to such an extent that it would no longer be a chorus, but a delay with modulation (not a flanger). The whole concept of Little Angel was to keep the delay time to a minimum by using that 100R resistor and modulation pin 2 instead of pin 6.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: YouAre on September 22, 2010, 02:55:23 PM
Did anyone uh....replace the 100r resistor at pin 6 (or whichever is the delay time pin, totally forgot) with an LDR that's controlled by the same LFO or another lfo? Cause that could make for a pretty sweet flanger.....right?

Replacing the 100R with a LDR would increase the delay time of the PT2399 to such an extent that it would no longer be a chorus, but a delay with modulation (not a flanger). The whole concept of Little Angel was to keep the delay time to a minimum by using that 100R resistor and modulation pin 2 instead of pin 6.

I only suggested this for 2 reasons. First being that I'm remembering back to the echo base/other delays with modulation, that modulation is achieved by "wiggling" the delay time pot. Secondly, I just built a small clone, and i noticed that when I played around with the delay time, I either got modulation or flanging (depending on the timing cap). I also noticed that some chorus pedals out there have a "delay time" pot, I figured it might be an interesting addition.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: blooze_man on September 23, 2010, 01:18:53 AM
I built this yesterday (pictures in the "pictures" forum). It really sounds nice and the PCB layout is good.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: andreaps72 on September 23, 2010, 07:51:13 AM
But a Vero layout ?
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: daniel_venticinco on September 29, 2010, 11:50:01 PM
Olá para todos , meu nome é daniel, sou brasilieiro .

Acabo de montar o little angel chorus, fiquei surpreso com o resultado, fantastico, achei muito bom.
A unica mudança que fiz foi usar os pots de 100K, o restante dos componentes são o mesmo do esquema original.
Me perdoem por não escrever em inglês  pois não domino o idioma, e  não sou favoravel a o uso de tradutores.
Agora posso tocar Nirvana... rsrsrs....

Abraços a todos e muito obrigado ao pessoal do forum que me abriu uma porta para um pedal complicado de se montar.
Abraços e Felicidades..
Daniel Venticinco ;D
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: ~arph on September 30, 2010, 06:01:44 AM
 ??? ??? ???

english please
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: frequencycentral on September 30, 2010, 07:28:42 AM
^^^

I think he likes it! He used 100k for both pots. Now he can sound like Nirvana.....obrigado!! ;D
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: ~arph on September 30, 2010, 08:07:36 AM
Yes that was the same impression I had.. Though I don't typically associate Nirvana with chorus..  ;D
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: deadastronaut on September 30, 2010, 08:09:33 AM
fantastico!..... :icon_mrgreen:
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: markeebee on September 30, 2010, 09:09:05 AM
That's spooky......here's a post I made earlier this morning......

http://www.diystompboxes.com/smfforum/index.php?topic=87287.msg733482#msg733482 (http://www.diystompboxes.com/smfforum/index.php?topic=87287.msg733482#msg733482)
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Slade on September 30, 2010, 02:02:02 PM
Olá para todos , meu nome é daniel, sou brasilieiro .

Acabo de montar o little angel chorus, fiquei surpreso com o resultado, fantastico, achei muito bom.
A unica mudança que fiz foi usar os pots de 100K, o restante dos componentes são o mesmo do esquema original.
Me perdoem por não escrever em inglês  pois não domino o idioma, e  não sou favoravel a o uso de tradutores.
Agora posso tocar Nirvana... rsrsrs....

Abraços a todos e muito obrigado ao pessoal do forum que me abriu uma porta para um pedal complicado de se montar.
Abraços e Felicidades..
Daniel Venticinco ;D

Hi, everyone, my name is Daniel, I'm brazillian.

I just mounted the Little Angel Chorus, I'm surprised about the result, fantastic, I found it's very good.
The only change I made was to use 100k pots, the rest of components are the same as in the original schem.
Sorry for not write in english but I don't dominate the idiom and I don't like using translators.
Now I can play Nirvana... rsrsrs...

Cheers to everyone and many thanks to the forum staff who has opened me a door to a pedal that was complicated to build.
Hugs and congratulations!
Daniel Venticinco ;D


;D
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: ~arph on October 01, 2010, 03:20:36 AM
 ;D

Well that explains it
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Pigyboy on October 01, 2010, 06:10:30 AM
Slade-All Seeing All Knowing :)
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: boog on October 01, 2010, 02:20:42 PM
built it, loved it, but tweeked it: was experimenting with different value pots off of pin 6 to go from chorus to delay and, ummm, hooked up a 24v adaptor instead of the usual.  :icon_redface: poof! so a quick check of everything tells me that the only components i used not rated for that much were the two 10uf in the LFO & the NE5532.  I can't find anything on the 2399. did i nuke that as well? i built this on perfboard and i'd like to think i don't have to redo all that. i replaced the 5532 and it passed signal again, but there's a loud buzz.  i only have one more 2399 so i don't wanna swap that in if there's something else wrong.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Earthscum on October 01, 2010, 02:53:07 PM
pop out the PT chip and turn the unit on and make sure you are still getting 5V on your regulator. I believe the lower rated regs can only tolerate 15V (don't quote me on that). Your regulator may have saved the PT, dunno... I'd assume I blew the PT if the reg works.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: boog on October 01, 2010, 03:10:45 PM
you are correct sir! 5.05V on the regulator (powerful ratshack rated for 35V). swapped chipped, beautiful again. bummer about the PT tho, really wanted to make another one of these and didn't wanna spend any money for awhile. oh well. thanks again, both to you for the help and frequencycentral for this sweet little circuit!  ;D ;D  ;D
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: frequencycentral on October 01, 2010, 03:14:12 PM
I think the regulator should have survived. 78L05 are rated for 35 volts. But that doesn't mean the PT2399 survived too. Yeah, it's still only getting 5v at it's VCC (pin 1) so would have survived in that respect, but it's REF (pin 2) may have received a big fat lot of voltage from the LFO running at 24 volts.

Ok boog, you posted while I was typing - glad it's working again and sounding sweet!
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: boog on October 01, 2010, 03:17:56 PM
sneaky that way sometimes, like a cat with a xylophone tied around it's neck.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Scruffie on October 01, 2010, 03:19:08 PM
So... Simplified BOSS DC-2 Anyone?  :icon_mrgreen:
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: frequencycentral on October 01, 2010, 03:28:42 PM
So... Simplified BOSS DC-2 Anyone?  :icon_mrgreen:

I spit on your DC-2 with it's HUGE PCB (http://img.villagephotos.com/p/2005-2/951008/DSC03791.JPG) and it's unneccesarily complex schematic (http://www.freeinfosociety.com/electronics/schemview.php?id=123)!!  :icon_mrgreen:
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Scruffie on October 01, 2010, 03:32:59 PM
So... Simplified BOSS DC-2 Anyone?  :icon_mrgreen:

I spit on your DC-2 with it's HUGE PCB (http://img.villagephotos.com/p/2005-2/951008/DSC03791.JPG) and it's unneccesarily complex schematic (http://www.freeinfosociety.com/electronics/schemview.php?id=123)!!  :icon_mrgreen:
Wellll Your Mother was a Hamster And Your Father Smelled of Elderberries  :icon_mrgreen:
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: frequencycentral on October 01, 2010, 03:49:16 PM
bummer about the PT tho, really wanted to make another one of these and didn't wanna spend any money for awhile.

Yeah bummer. If it's any consolation, over the summer I paved my driveway using only PT2399 and LM13700 that I destroyed while originally breadboarding this circuit and Causality 4.  ::)
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: boog on October 01, 2010, 04:01:56 PM
that is unfortunate; casualty 4 is on my list, i spent the first year and a half building dirt boxes so now i've moved on to modulation. of course, i built my bench around dirt circuits so that means a whole bunch o' reinvesting.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Earthscum on October 02, 2010, 12:53:48 AM
So, I built a second LAC... this one has a horrible LFO thump! I'll play around with it tomorrow (and reread some posts). I didn't hear it until I plugged into my TKO, then I had a nice steady heartbeat. I'm gonna try running with the TL072 and see if the thumping goes away, cuz I don't hear it at all in my first build, and it's exact  same components except the IC and the depth pot.... just laid out on a DIP board instead of the nice PCB. Maybe some LFO mods in my future, lol.

I'll get pics up tomorrow... it's a pretty box!
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: boog on October 02, 2010, 10:57:27 AM
well here i was all prepped to show off my snazzy build and when i box it up i get nothing but the 'deathbuzz' again; standard troubleshooting procedures shall apply, but i think i'm doomed. so.......this lead me to a noob question: my 7805 is in one of those to-220 packages. rocket scientist here didn't heat sink it so when i boxed it, the 7805 bent over and touched the 5532, would the heat off of the 7805 zap the 5532? and isn't that tag at the top (where you mount it to the heat sink) a ground connection? so if it touched the enclosure it really shouldn't do anything?
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: John Lyons on October 02, 2010, 11:11:15 AM
There shouldn't be any heat with the regulator.
But shorting something out, yeah that would do it.
Don't know off hand about the tab being at ground or not.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: frequencycentral on October 02, 2010, 12:05:09 PM
.....and isn't that tag at the top (where you mount it to the heat sink) a ground connection? so if it touched the enclosure it really shouldn't do anything?

The metal tab is connected to COMMON (pin 2) and therefore is at 5 volts. You need to isolate it form the (grounded) enclosure or you'll have a short circuit. Use insulation tape.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: boog on October 02, 2010, 12:23:16 PM
oh bugger then; looks like i'll have to try that for round 3, so far no luck in troubleshooting and there is definately some heat being generated somewhere. lessons learned i spose.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: soggybag on October 02, 2010, 02:16:39 PM
I tried adding a 50K pot between the 100R and pin 6 of the 2399. Though this does work, you get a delayed signal, the sound was not very exciting. There is a single short delay and the modulation seems less obvious. The best sounds seem to be at the shortest delay times. There might be use for a smaller pot say 1K to 10K to adjust the delay length a small amount for different sorts of sounds.

I wonder if a regeneration pot might be more useful as a sort of resonance control?

I noticed on my build that I hear some hiss/noise. Not sure if this was there before I added the 50K pot or not. Though I don't think the pot itself would add any noise. I notice the noise seems to increase when I play. Have to sort this out before boxing up.

I mentioned this before but, I notice the LFO is not symmetrical. It seems a little lopsided. The lopsidedness seems to be effected by speed.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: frequencycentral on October 02, 2010, 02:20:08 PM
I wonder if a regeneration pot might be more useful as a sort of resonance control?

It's on my breadboard right now.  :D
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Pigyboy on October 02, 2010, 04:31:40 PM
ok, got it sorted
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: soggybag on October 02, 2010, 04:42:35 PM
I wonder if a regeneration pot might be more useful as a sort of resonance control?

It's on my breadboard right now.  :D
It's hard to keep up with you Rick, you are tireless!
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: clamup1 on October 02, 2010, 04:43:47 PM
hey i got mine to work. i had to reetch the whole thing but i got it. now lets see if i can put a switch on it and it still work. thanks for a great pedal
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: clamup1 on October 02, 2010, 04:47:56 PM
hey i got a stupid ?. is this pedal npn or pnp.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: earthtonesaudio on October 02, 2010, 04:59:44 PM
It's neither... and both.


NPN and PNP are different bipolar transistor types.  There are dozens, maybe hundreds, of each type in the ICs (integrated circuits) used in this project.  However there is not one single discrete (by itself, not part of an IC) transistor, either NPN or PNP, used in the build.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: clamup1 on October 02, 2010, 06:05:09 PM
its ok, i got it to work.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Barcode80 on October 02, 2010, 09:12:06 PM

You can also do it in MS Publisher, I just tested it. I made a grid 0.254mm (= 0.1") and scaled the pad spacings to that. Worked a treat.

Sorry about my first reply.... Here goes again...

I also do not have MS Publisher. As you can tell from my login, I work for the government. They do not give us cool software tools like MS Publisher. Any other ideas? Sorry to be a pain. Can anyone tell me a % to shrink this down to in order to get the sizes correct?
Any other ideas would be appreciated.

Just an FYI for everyone, all pcb transfers generated out of DIY layout creator are properly sized when printed at 72 dpi. You can use irfan picture viewer to print at different resolutions if you don't have a program to do so.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Barcode80 on October 02, 2010, 09:17:35 PM
Quote
oh well i got more coming.

5532 opamps are highly recommended (a little low on the input impedance, but a great driver on output).  Not to start a debate or anything, but between these and TL072 you are pretty well covered for anything you would want to build.  Someone is selling 50 5532's on Ebay for 10.99 (including shipping) at the moment.  If you plan to continue building DIY stompboxes, I would just order a nice supply.

This is good advice, but bear in mind that in LFO's and modulation especially, as mentioned before, the two can't be used interchangeably. I can say that due to the number of tremolos I have built with NE5532 that didn't work until I popped in a TL072. Not all duals are created equal... :)
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: boog on October 02, 2010, 11:48:36 PM
I tried adding a 50K pot between the 100R and pin 6 of the 2399. Though this does work, you get a delayed signal, the sound was not very exciting. There is a single short delay and the modulation seems less obvious. The best sounds seem to be at the shortest delay times. There might be use for a smaller pot say 1K to 10K to adjust the delay length a small amount for different sorts of sounds.

I wonder if a regeneration pot might be more useful as a sort of resonance control?

25k was i ended up using, after it falls out of 'chorus' it seemed pretty cool, though there was a snare like echo to the circuits echo. i liked the 'somethin aint right sound.' i too wondered about a resonance control, figured i'd try something out in the winter.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: culturejam on October 02, 2010, 11:51:14 PM
Just an FYI for everyone, all pcb transfers generated out of DIY layout creator are properly sized when printed at 72 dpi. You can use irfan picture viewer to print at different resolutions if you don't have a program to do so.

This is not my experience. For the older version, the output files are properly sized at 200 dpi. The new version (beta) outputs at 166 dpi. At least that's how it works with Photoshop.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Barcode80 on October 03, 2010, 12:19:09 AM
Sorry, I mistyped. The old version outputs the image at 72 dpi. The print size I've found to be best is 200.25 dpi. Perfect fit every time. Thanks for the correction, don't know where my mind was!
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Earthscum on October 03, 2010, 01:31:01 AM
So, I built a second LAC... this one has a horrible LFO thump!

Word of advice: choose your pot and board locations carefully. I am getting LFO bleedthrough from the pots to one of the audio paths in the board. Fun fun fun!  ;D

I'm lazy, so I'll probably just do a ground plane shield between the back of the pots and the board... worked decent on testing, we'll try it tomorrow, along with some shielded cable in/out. I'm tired of soldering on this thing, hehe. I wanna move on to my next project (probably a wah).
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Barcode80 on October 03, 2010, 02:36:55 AM
I took a risk since some people have verified the layout and built it up completely without testing. I will play through tomorrow and ensure it wasn't a mistake!

(http://i85.photobucket.com/albums/k42/goodoldpatrick/100_1009.jpg)
(http://i85.photobucket.com/albums/k42/goodoldpatrick/100_1010.jpg)
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Pigyboy on October 03, 2010, 02:38:54 AM
Hi,
Ok I went thru the whole thread and I think if I want to build the standard two knob version I use the layout on page 9. Yes Rick?
Thank you
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: juansolo on October 03, 2010, 05:32:49 AM
Super, smashing, lovely.

(http://juansolo.demon.co.uk/stompage/images/angel-o.jpg)

(http://juansolo.demon.co.uk/stompage/images/angel-i.jpg)
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: frequencycentral on October 03, 2010, 05:46:53 AM
Hi,
Ok I went thru the whole thread and I think if I want to build the standard two knob version I use the layout on page 9. Yes Rick?
Thank you

Yeah, that's the 1590A layout. Both layouts I've posted follow the schematic and part values in post #1.

Nice to see some finished build photos!
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Govmnt_Lacky on October 03, 2010, 09:48:09 AM
Still unsure about good pot values for this build.

Can someone help me out with what potentiometer values work best in this circuit? I know Rick used 100K for Speed and 470K for Depth but I have also read that some poeple liked 100K for both.

Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Pigyboy on October 03, 2010, 10:05:57 AM
I am getting ready to build this too and Rick suggests the 470K. I should have it done tomorrow sometime I hope so I will post my results.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Barcode80 on October 03, 2010, 10:58:36 AM
Strangely enough, I used the NE5532 with a 500k pot for depth and a 100k spot for speed, but I'm experiencing that all the depth and speed both are bunched at the end of the pot's rotation. I'm assuming I will need to go with the 100k depth. THoughts?
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: waltk on October 03, 2010, 11:13:21 AM
Quote
but I'm experiencing that all the depth and speed both are bunched at the end of the pot's rotation. I'm assuming I will need to go with the 100k depth. THoughts?

Rick had a good point with this post:

Quote
Re. Depth pot value debate:

The more minimum settings shouldn't be dismissed out of hand. Take away (most of) the modulation and you've got automatic double tracking, which we don't seem to talk about much around here. ADT has the effect of thickening the sound as if two people were playing the same part in unison. You might not notice the thickening until you bypass it - then your sound will seem thin and weedy by comparison!    Process your vocalist through the Little Angel at minimum settings - he/she/it will love you forever.

The ADT you get with the depth pot turned down all the way is a cool effect in it's own right.  Yet you don't seem to significant chorus effect 'til you get to the last 20% of the pot rotation.  My solution was to change the depth pot to 100K, and add an SPDT switch and a 470K resistor - so that in one switch position, it's like having the 470K depth pot turned down all the way (you get ADT).  In the other switch position it's like having the full rotation of the depth pot cover the top 20% of the 470K pot (from the original schematic).
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: frequencycentral on October 03, 2010, 11:35:45 AM
Quote
but I'm experiencing that all the depth and speed both are bunched at the end of the pot's rotation. I'm assuming I will need to go with the 100k depth. THoughts?

Rick had a good point with this post:

Quote
Re. Depth pot value debate:

The more minimum settings shouldn't be dismissed out of hand. Take away (most of) the modulation and you've got automatic double tracking, which we don't seem to talk about much around here. ADT has the effect of thickening the sound as if two people were playing the same part in unison. You might not notice the thickening until you bypass it - then your sound will seem thin and weedy by comparison!    Process your vocalist through the Little Angel at minimum settings - he/she/it will love you forever.

The ADT you get with the depth pot turned down all the way is a cool effect in it's own right.  Yet you don't seem to significant chorus effect 'til you get to the last 20% of the pot rotation.  My solution was to change the depth pot to 100K, and add an SPDT switch and a 470K resistor - so that in one switch position, it's like having the 470K depth pot turned down all the way (you get ADT).  In the other switch position it's like having the full rotation of the depth pot cover the top 20% of the 470K pot (from the original schematic).

Phew! At least someone read my ADT post!  :icon_eek:  Nice mod Walt!
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Earthscum on October 03, 2010, 11:58:40 AM
Phew! At least someone read my ADT post!  :icon_eek:  Nice mod Walt!

That's basically the trick I take advantage of with the added 5k delay pot. The effect disappears on the lower notes on bass, so increasing the delay a small amount covers a bit more range of effect.

I gotta get pics up for ya... even though I'm not done. I think I gotta re-etch a new board. I yanked the whole thing out and found I'm getting LFO thumping through the board itself. ugh!
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Govmnt_Lacky on October 03, 2010, 12:40:28 PM
The ADT you get with the depth pot turned down all the way is a cool effect in it's own right.  Yet you don't seem to significant chorus effect 'til you get to the last 20% of the pot rotation.  My solution was to change the depth pot to 100K, and add an SPDT switch and a 470K resistor - so that in one switch position, it's like having the 470K depth pot turned down all the way (you get ADT).  In the other switch position it's like having the full rotation of the depth pot cover the top 20% of the 470K pot (from the original schematic).
I am a bit confused  ???

So, the way that the 470K depth pot is wired on the Little Angel, (with lugs 2 & 3 connected and Lug 1 open) as the pot is turned CCW or down, does the resistance go UP or DOWN?

 
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: waltk on October 03, 2010, 03:01:45 PM
Quote
So, the way that the 470K depth pot is wired on the Little Angel, (with lugs 2 & 3 connected and Lug 1 open) as the pot is turned CCW or down, does the resistance go UP or DOWN?

As you turn the pot "down" (CCW), the resistance goes up - to 470K ohms if you're using a 470K pot; to 100K if you're using a 100K pot.  As you turn the pot "up" (CW), the resistance goes down to zero ohms - regardless of what value pot you are using.  So simply replacing the 470K pot with a 100K pot (wired the same way - lugs 2 and 3), and using the full rotation, is exactly like using the top (CW) ~20% of the 470K pot.

The switch on my build is wired so that the resistance is either 470K (simulating having a 470K pot turned all the way down), or somewhere between 0 and 100K depending on the rotation of the pot.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Govmnt_Lacky on October 03, 2010, 03:07:54 PM
The switch on my build is wired so that the resistance is either 470K (simulating having a 470K pot turned all the way down), or somewhere between 0 and 100K depending on the rotation of the pot.

I see now. I originally thought you were putting the 470K resistor IN SERIES with the 100K pot. I see now that it is EITHER/OR.

So you get the max ADT with one side of the switch, and the FULL pot rotation of the 100K with the other side of the switch. Good deal!  :icon_cool:
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Earthscum on October 03, 2010, 11:43:13 PM
(http://img687.imageshack.us/img687/8623/littleangelchorus.jpg)
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Pigyboy on October 04, 2010, 05:10:41 AM
(http://img687.imageshack.us/img687/8623/littleangelchorus.jpg)
Oh EarthScum that is beautiful. Looks like you have signed up to do a screen printing tutorial!
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Govmnt_Lacky on October 04, 2010, 08:02:26 AM
(http://img687.imageshack.us/img687/8623/littleangelchorus.jpg)

Must see the gut shots on this one! Absolutely beautiful!!
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Earthscum on October 04, 2010, 09:27:40 AM
oh yeah... forgot about the Gratuitous Gutshot!  ;D

(http://img684.imageshack.us/img684/5223/littleangelchorusgutz.jpg)

Not the smartest layout decision... more like experimenting, since I know it's gonna be around to fix. Testing out a couple things: solid core wire layout, Krylon paint and etching primer. Probably won't do the wire trick again... looks nice, but it's a pain to do.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Barcode80 on October 04, 2010, 10:45:26 AM
I recently switched to solid core wire, and I will likely never use stranded again. It's just so much tidier...
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Pigyboy on October 04, 2010, 02:06:29 PM
oh yeah... forgot about the Gratuitous Gutshot!  ;D

(http://img684.imageshack.us/img684/5223/littleangelchorusgutz.jpg)

Not the smartest layout decision... more like experimenting, since I know it's gonna be around to fix. Testing out a couple things: solid core wire layout, Krylon paint and etching primer. Probably won't do the wire trick again... looks nice, but it's a pain to do.
Is that the millenium switching array in there?
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: culturejam on October 04, 2010, 03:03:26 PM
Earthscum, are you finding that an increased delay time results in noise/hiss?
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Brymus on October 04, 2010, 03:29:04 PM
Beautiful build Earthscum!
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Earthscum on October 04, 2010, 06:27:03 PM
Earthscum, are you finding that an increased delay time results in noise/hiss?

Actually, I did notice that a little bit, but this build is fairly hissy all around. MY slap-together works great, even with wires crammed in every orfice of the board.

And, yes... that's a millennium. I used a blue LED and ended up using 51k as a drop resistor... never saw that before. All other LED's (except clear yellow ones) had NO light at all, but this setup I used the 51k (not 5.1k!) and had to use a 100k parallel to the LED to get the fet to turn all the way off. Usually I'm sitting on a 3.3k and somewhere around a 4.7k parallel. I thought it was my fet... nope. diode? nope... just the blue LED.  Not alot of current through it, so I'm definitely not complaining!
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Pigyboy on October 04, 2010, 06:42:25 PM
Earthscum, are you finding that an increased delay time results in noise/hiss?

Actually, I did notice that a little bit, but this build is fairly hissy all around. MY slap-together works great, even with wires crammed in every orfice of the board.

And, yes... that's a millennium. I used a blue LED and ended up using 51k as a drop resistor... never saw that before. All other LED's (except clear yellow ones) had NO light at all, but this setup I used the 51k (not 5.1k!) and had to use a 100k parallel to the LED to get the fet to turn all the way off. Usually I'm sitting on a 3.3k and somewhere around a 4.7k parallel. I thought it was my fet... nope. diode? nope... just the blue LED.  Not alot of current through it, so I'm definitely not complaining!
Thanks for the lowdown David. Where are you getting your momentary switches? Oh, and how about the screen printing tutorial? :P
What band do you play in anyways?
Cheers,
Chris
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Scruffie on October 04, 2010, 07:20:09 PM
Earthscum, are you finding that an increased delay time results in noise/hiss?

Actually, I did notice that a little bit, but this build is fairly hissy all around. MY slap-together works great, even with wires crammed in every orfice of the board.

And, yes... that's a millennium. I used a blue LED and ended up using 51k as a drop resistor... never saw that before. All other LED's (except clear yellow ones) had NO light at all, but this setup I used the 51k (not 5.1k!) and had to use a 100k parallel to the LED to get the fet to turn all the way off. Usually I'm sitting on a 3.3k and somewhere around a 4.7k parallel. I thought it was my fet... nope. diode? nope... just the blue LED.  Not alot of current through it, so I'm definitely not complaining!
With Ultra Bright Blues I always found the millenium only worked with 10k & 10k for both resistors or else the LED just blew up.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Earthscum on October 04, 2010, 08:56:54 PM
Thanks for the lowdown David. Where are you getting your momentary switches? Oh, and how about the screen printing tutorial? :P
What band do you play in anyways?
Cheers,
Chris

This one is DPDT latching, mechanical true bypass.

Been getting requests for that lately... probably be more of a bill of materials, and how to use them... the actual screening is easy... just feel, patience, and getting your hands on. Care and handling of materials is actually more crucial... but, I may do a PDF writeup for the DIY'er who's like me and tries to dive in head first.

And, band is in the sig  ;D
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Pigyboy on October 05, 2010, 03:13:21 AM
You know I had looked at and pondered your sig but didn't click it but now I clicked it an dyou FB like button too. Great name, kind of Ween-ish!
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: boog on October 05, 2010, 05:21:32 PM
fixed it!  :icon_smile:

(http://i868.photobucket.com/albums/ab246/boogaldige/101005_165957.jpg)
(http://i868.photobucket.com/albums/ab246/boogaldige/101005_170512.jpg)

really gotta get a camera
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: daniel_venticinco on October 05, 2010, 06:11:37 PM

Govmnt_Lacky ,por favor poste seu esquema, achei interessante os controles que vc adicionou ao seu projeto.
----------------------------------------------------------------------------------------------------------------------------------

please post your schema, I found it interesting that the controls you added to your project.

Daniel.


Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Earthscum on October 05, 2010, 07:12:22 PM
Govmnt_Lacky ,por favor poste seu esquema, achei interessante os controles que vc adicionou ao seu projeto.
----------------------------------------------------------------------------------------------------------------------------------
please post your schema, I found it interesting that the controls you added to your project.

Daniel.

The white & blue one is mine. I have the pot mods posted on page 8 (http://www.diystompboxes.com/smfforum/index.php?topic=86297.140).
...

I think I have a new mod... taking the LED+ from the regulator. I have a pedal that turns on, but no sound... the 9V got too low, but it is still powering the LED. Shouldn't be hard by any means, but at least you will be able to tell when your audio is shut down (when the PT is no longer getting voltage from the reg).
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: daniel_venticinco on October 05, 2010, 07:41:22 PM

Govmnt_Lacky

Desculpe-me  pela confusão,  não havia visto que o projeto com os mods seria o da pagina 8, obrigado por esclarecer para mim.
mais uma vez me perdoem por não conhercer bem a lingua inglesa.


Sorry for the confusion, had not seen the project with the mods would be on page 8, thanks for clarifying for me.
Once again forgive me for not Getting started and the English language.


thanks.
DAniel

Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: askwho69 on October 08, 2010, 03:57:26 AM
Earthscum! thats a beautiful and very clean@@@@ no Doubt your room is very Clean!
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: ppatchmods on October 13, 2010, 02:29:03 PM
anyone worked up a vero layout for this yet? i've tried my hand at it and it was an epic fail...
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: thehoj on October 14, 2010, 12:12:02 AM
I just did this up, and can't help but think I might be able to make use of more depth for a bit more versatility. How might I go about accomplishing that with this circuit?

By the way, I really love the design, and I think it'll have a permanent place on my board. I love the subtle shimmery-ness I can add to my sound.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Earthscum on October 14, 2010, 12:31:29 AM
2-5k pot with the 100R as a limiting resistor works great. I use 10k, but I'm a bassist with a weird sense of sound.

Page 8, second post down has the mods that I find useful and use.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: thehoj on October 14, 2010, 12:45:33 AM
2-5k pot with the 100R as a limiting resistor works great. I use 10k, but I'm a bassist with a weird sense of sound.

Page 8, second post down has the mods that I find useful and use.

Yea, actually I did do those mods, I used a 5K with a 100r limiting resistor, but that seems to affect the delay time, not really the depth.. Unless I've done it wrong somehow..
Also, the level mod you showed doesn't seem to work for me.. It doesn't seem to adjust the output signal at all.. I need to look at that again, but I think I did that right also.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: frequencycentral on October 14, 2010, 02:33:27 AM
Whenever I hear 'not enough depth' I think maybe there's something wrong, as I tweaked the design for what I considered gave just a lttle too much depth. Is the opamp Ne5532? Anyway, reducing R13 or replacing R13 with a jumper will increase the depth to too much/way too much respectively.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: thehoj on October 14, 2010, 08:43:08 AM
I am using an Ne5532, and I've actually got a 30K resistor in place of R13. I'm probably just looking for more versatility than this pedal should have.
I'll try a few different values though. Thanks.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Pigyboy on October 14, 2010, 05:44:27 PM
Works Great! Just the basic build no mods and it is sweet. Into the 1590A tomorrow and pictures. Thanks Rick!
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: frequencycentral on October 14, 2010, 05:56:09 PM
Damn! I was hoping to complete the first 1590A build. I'm just in the process of producing the etched enclosure. I'm about two days behind you.....
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: roseblood11 on October 14, 2010, 07:26:23 PM
Great project!

Has someone made a vero layout in the meantime? Renegadrian talked about that, but it seems he never finished it?
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: deadastronaut on October 15, 2010, 03:15:56 AM
+1....great sound on that clip rick.....very cool project..... :icon_cool: :icon_cool: :icon_cool:

been following this thread, waiting for the dust to settle on the inevitable mods.... 8)

i'd like to see a vero too...coz im too lazy to 'print, saw, etch, n drill'.... :P rob....
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Pigyboy on October 15, 2010, 08:45:03 AM
Ok, It fits in the 1590A. Is this the first finished mini-box build?  It gave me fits getting it in there. It won't fit with sockets or anything taller than 7 or 8 mm above the board. It does fit clean and it sounds beautiful. I will make a clip today. Looking forward to Rose (my wife) using at her next gig with her new Taylor ;D. That is if she doesn't want to use it to sweeten up her Little Angelic voice. I think I will get her to help make the clip doing a proper guitar and vocal demo.
(http://i852.photobucket.com/albums/ab86/pigyboy_2009/LittleAngel2.jpg)
(http://i852.photobucket.com/albums/ab86/pigyboy_2009/LittleAngel1.jpg)
(http://i852.photobucket.com/albums/ab86/pigyboy_2009/LittleAngelGuts.jpg)
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Earthscum on October 15, 2010, 09:38:55 AM
What? No battery?  :icon_wink:
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: frequencycentral on October 17, 2010, 09:38:40 AM
Here's mine!

(http://dl.dropbox.com/u/967492/LA%20Front.jpg)
(http://dl.dropbox.com/u/967492/LA%20Guts.jpg)
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Pigyboy on October 17, 2010, 09:50:54 AM
Wow Rick! . Looks great. I couldn't get mine in the box with the sockets. What kind of jacks did you end up using?
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Mr. Slave on October 17, 2010, 01:59:52 PM
Hey
I'm  mewby, and tried a veroboard layout for the Little angel circuit. It's my first time going from schematic to vero layout, so I invite anyone to examine or try it.  I will order the material just tomorrow, so i can try not before 10 days. Can anyone see anything wrong?
(http://)
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Mr. Slave on October 17, 2010, 02:28:43 PM
sorry....
http://www.aronnelson.com/gallery/main.php/v/diyuser/angioletto.gif.html?g2_imageViewsIndex=1
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: deadastronaut on October 17, 2010, 02:41:26 PM
cuts under the ic?... ;) .....

Interesting. I like the simplicity of the circuit. A board wouldn't even be necessary, unlike most other chorus schemes floating around out there. What opamps did you use?

i was looking forward to this interesting boardless version of this build  ??? :icon_mrgreen:
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Mr. Slave on October 17, 2010, 05:04:37 PM
Of course....
cuts under the ics....
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: frequencycentral on October 17, 2010, 06:03:51 PM
sorry....
http://www.aronnelson.com/gallery/main.php/v/diyuser/angioletto.gif.html?g2_imageViewsIndex=1

I find vero really hard going, but I spotted a couple of errors (there might be more, I didn't check it all):


It would also help if you used the correct DIYLC part for the electo caps, to avoid incorrect orientation.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Mr. Slave on October 18, 2010, 02:39:49 AM
New vero with corrections

http://www.aronnelson.com/gallery/main.php/v/Schematics-etc/angioletto.gif.html

Thank you Rick....
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: deadastronaut on October 18, 2010, 04:04:58 AM
c5 should be to ground . ;)
cuts under c12?????why!.

i think we would all be better off doing the pcb. looks like it might end up big , and maybe problematic, etc..

nice to see mr slave  have a go at it though!..it took me a while to get used to converting from schematic
to vero, you didnt choose an easy one by the way!.... :icon_mrgreen: rob.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Mr. Slave on October 18, 2010, 05:16:37 AM
Thank you Rob
"c5 should be to ground"...that was an oversight
"cuts under c12?why!" ... I moved everything but the cuts under c12
...soon correct layout...
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Pigyboy on October 18, 2010, 06:50:53 AM
If I even see the word 'vero' I break out in a rash :icon_eek:
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: deadastronaut on October 18, 2010, 06:55:44 AM
If I even see the word 'vero' I break out in a rash :icon_eek:

 :icon_mrgreen:
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: frequencycentral on October 18, 2010, 07:11:17 AM
Y'know, I've started a few vero layouts (to benefit all mankind), I place half a dozen components then I think to myself "@#$% this @#$%ing mother@#$%er !! If people are 'individual' enough to want to use @#$%ing vero over a superior media they can just make their own @#$%ing vero layouts !!" I HATE vero with a vengence.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Pigyboy on October 18, 2010, 07:14:54 AM
Help us Renegadrian! You are our only hope....
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: deadastronaut on October 18, 2010, 07:22:06 AM
erm...perf? :icon_mrgreen: only joking..... 8)

i'll get my coat.......... ;)
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Mr. Slave on October 18, 2010, 08:12:47 AM
I'm all a rash ;D :icon_redface:

http://www.aronnelson.com/gallery/main.php/v/Schematics-etc/angioletto_001.gif.html?g2_imageViewsIndex=1
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: deadastronaut on October 18, 2010, 08:22:43 AM
 :icon_mrgreen: funny...

rob has left the building....with his coat on.... :P



i'll  put this on here on mr slaves behalf...to cover his rash. :icon_mrgreen:
(http://dl.dropbox.com/u/7464107/embarrassed_pic.jpg)
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Govmnt_Lacky on October 18, 2010, 08:30:05 AM
Y'know, I've started a few vero layouts (to benefit all mankind), I place half a dozen components then I think to myself "@#$% this @#$%ing mother@#$%er !! If people are 'individual' enough to want to use @#$%ing vero over a superior media they can just make their own @#$%ing vero layouts !!" I HATE vero with a vengence.

+1  ;D
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Mr. Slave on October 18, 2010, 12:18:02 PM
Ahhhhhhrghhhhhh :o
the last one:
http://www.aronnelson.com/gallery/main.php/v/Schematics-etc/angioletto_002.gif.html?g2_imageViewsIndex=1
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: frequencycentral on October 19, 2010, 12:27:00 PM
A guy over at FSB just posted a pretty neat looking vero layout (unverifed), I'm sure he won't mind if I post it here:

(http://www.sabrodesign.com/wp-content/uploads/2010/10/Little-Angel.gif)

Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Pigyboy on October 19, 2010, 02:37:01 PM
FSB?
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: BoxOfSnoo on October 19, 2010, 02:41:34 PM
FSB?

Either front-side bus if you're talking about a computer, or more likely the other DIY stompboxes forum whose name we don't mention :)
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: defaced on October 19, 2010, 06:44:57 PM
Free Stomp Boxes.org
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Pigyboy on October 19, 2010, 09:34:45 PM
Thanks guys,
Acronyms and politics are not my strong suit :-X
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Pakaloabob on October 24, 2010, 08:34:45 PM
I am having a little trouble with this circuit on the breadboard. It seems that my supply voltage, which is 9v volts from a One Spot power supply, drops down to 6.3v. I believe I have located the issue to be the 78L05 regulator. The one I am using is to-92 package and I am using the PCB layout as a guide for hooking it up.
Anyone have a suggestion to correct my problem. I am seriously excited to try this circuit as soon as I get past this issue.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Barcode80 on October 24, 2010, 10:26:10 PM
I'm confused. the 78L05 should drop the 9 volts down to 5 (or 6 with tolerances). Am I misunderstanding your question?
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Pakaloabob on October 24, 2010, 11:03:14 PM
Yes, the regulator does drop the voltage it outputs to 5 volts, but when it is in the circuit, my supply voltage to the rest of the circuit  drops down to about 6.3v. That means that the voltage fed to pin 8 of the dual op-amp (NE5532 in my case) is only at 6.3 volts when it should be 9. In addition, the voltage fed to the non-inverting input on one side of the op-amp is also not what it should be. 
Something is pulling my voltage down, but I can't quite figure out what it is. When I remove the 78L05, the supply voltage is back to 9 volts, when the regulator is in the circuit, it reads 6.3v. I have tried another regulator and also another PT2399 with the same results.
I just thought someone might have had a similar issue, or be able to point me in the right direction.
 
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Govmnt_Lacky on October 25, 2010, 11:43:46 AM
Yes, the regulator does drop the voltage it outputs to 5 volts, but when it is in the circuit, my supply voltage to the rest of the circuit  drops down to about 6.3v. That means that the voltage fed to pin 8 of the dual op-amp (NE5532 in my case) is only at 6.3 volts when it should be 9. In addition, the voltage fed to the non-inverting input on one side of the op-amp is also not what it should be. 
Something is pulling my voltage down, but I can't quite figure out what it is. When I remove the 78L05, the supply voltage is back to 9 volts, when the regulator is in the circuit, it reads 6.3v. I have tried another regulator and also another PT2399 with the same results.
I just thought someone might have had a similar issue, or be able to point me in the right direction.
 


Sounds like you need to start checking resistor values and solder bridges on or around your voltage regulator. R1 shorted to the ground post of the regulator?

Good Luck  ;D
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Pakaloabob on October 25, 2010, 08:06:43 PM
Well, it turns out all I had to do was run the circuit off a battery instead of a power supply.  :icon_redface:
I really wish I knew why the power supply wasn't working properly for this circuit. If someone has any idea, I would love to hear. At any rate, things are working fine off the battery so I won't get too worked up.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: deadastronaut on October 26, 2010, 03:30:16 AM
Well, it turns out all I had to do was run the circuit off a battery instead of a power supply.  :icon_redface:
I really wish I knew why the power supply wasn't working properly for this circuit. If someone has any idea, I would love to hear. At any rate, things are working fine off the battery so I won't get too worked up.

just as a note : i had the very same problem with a 'zombie chorus' worked fine on a battery, but wouldnt 'chorus' on my psu...
i ended up having to put a regulator on the dc socket..and it worked fine...hope this helps....
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Pakaloabob on November 01, 2010, 01:49:42 PM
Thanks, Rob.
At least I know I'm not completely crazy if it happens to someone else.
Another funny thing I noticed is that I can play with it running off a battery, change to a power supply and get no modulation, then remove the power suppply and reattach battery and still get no effect for a little while. If I leave it for a few minutes it will work fine on the battery!
Is it possible that the LFO somehow latches until the proper voltage is applied?
Like I said in an earlier post, for some reason my power supply does not provide 9 volts when attached to the Little Angel circuit, but a battery does. Since the PT2399 voltage is regulated, only the dual-opamp would be affected by this voltage drop. Which is why I think the LFO is the issue.
I wish I had another power supply to test with. I was planning on building the AMZ power supply. Maybe this will be the motivation I need.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: nick d on November 01, 2010, 08:28:19 PM
              This is driving me crazy - if anyone can help , I would appreciate it immensely.
               I'm using Ricks schematic Version 2 updated 11/08/10 , all components stock .
               The vero layout is from Harald Sabro Bolstad , posted on this forum by ( I think ) Rick .
               I have altered the layout only slightly , to avoid any jumpers running under ICs .
               I've checked for shorts throughout , and for continuity everywhere I can see .
               The test results are :-
                                               By-passed - normal output
                                               Effect - sounds normal , perhaps a tiny volume drop
                                               Audio probe - as effect on pin 1 opamp then the same at pin 15 PT2399 , no sound anywhere else on this IC . A gentle thumping sound from pin 7 on the
                                                opamp , varying with speed pot - I guess this means the opamp works .
                                               
                                              Voltages -
                                                              IC 1  1) 5.21 V     
                                                                      2) 4.87 V
                                                                      3)  4.77 V
                                                                      4)   0.00 V
                                                                      5)  varying 2.5 - 3.5 V
                                                                      6)       "     2.5 - 3.5 V
                                                                       7)      "     1.4 - 7.8 V
                                                                      8)  8.56 V (normal output of my PSU ) 
                                                                       

                                                             IC2     1) 5.01 V
                                                                       2) varying 2.49 - 2.54 V
                                                                       3) 0.00 V
                                                                       4)0.00 V
                                                                       5)  5.01 V 
                                                                       6)  as pin 2
                                                                       7 + 8)  0.001 V
                                                                       9 - 16) all as pin 2 , i.e.minor variation around 2.5 V

                                 Also , I pulled the 2399 from another pedal that was already working , thinking that the new one was a duffer - no change .
                                 
                                 I know the answer must be right in front of me , but I'll be damned if I can see it - HELP !!!!!!!!!!!!!                                 
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: frequencycentral on November 01, 2010, 08:32:22 PM
My first guess with vero would always be microscopic continuity on the cut tracks - check it out with a continuity probe.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: nick d on November 01, 2010, 08:43:31 PM
                      Already done that (several times ) but I'll do it a few times more . I was hoping something in the voltages might give us a pointer - the fact that I get a signal on pin 15 but nowhere else makes me think the fault is in that area - I'll keep on digging !
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: nick d on November 01, 2010, 09:29:50 PM
                 RESULT!!!!!!
                   The 100R from pin 6 to ground was OC at the ground end - it was the last one in the drawer and had been cut short previously , so I missed it , hidden between 2 other wires .
                   
                   Anyway , it now works - and might I say how lovely it sounds !
                   Thanks , Rick - you're a genteman and a scholar , as we used to say !
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Govmnt_Lacky on November 01, 2010, 09:35:38 PM
OK, I built this Lil' Angel on PCB for a 1590A. Only wired it for wall wart power from DC jack. I get bypass no problem, when I engage the circuit, it seems like the depth pot does not work at all (no change in modulation) however, the speed pot seems to do something when I crank it between 80-100%. I get a subtle vibrato effect. I used 100KB for both pots. Here are some voltages.

Opamp (5532)
Pin1) cycles on and off from 0V to ~1.4V (This looks wrong)
Pin2) 2.8-3.2V
Pin3) 2.8-3.2V
Pin4) 0
Pin5) 4.75V
Pin6) 4.9V
Pin7) 5.2V
Pin8) 9.18V

2399
Pin1) 5V
Pin2) 2.4-2.5V
Pin3) 0
Pin4) 0
Pin5) 2.6V
Pin6 - Pin8) 0.7V
Pin9 - Pin16) 2.4-2.5V

Voltage converter seems to work correctly.

Any help is appreciated. Thanks.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: nick d on November 01, 2010, 09:53:57 PM
                  I've just got this going , having got stuck and posted the voltage readings .
                  Looks like you're using pins 3-2-1 for LFO - your readings tally with mine except for pin 1 , which looks very low .
                    Could be a low-value resistor shorted to ground - I see a 4k7 in that area - try looking around there .
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Govmnt_Lacky on November 02, 2010, 07:59:48 AM
OK, I built this Lil' Angel on PCB for a 1590A. Only wired it for wall wart power from DC jack. I get bypass no problem, when I engage the circuit, it seems like the depth pot does not work at all (no change in modulation) however, the speed pot seems to do something when I crank it between 80-100%. I get a subtle vibrato effect. I used 100KB for both pots. Here are some voltages.

Opamp (5532)
Pin1) cycles on and off from 0V to ~1.4V (This looks wrong)
Pin2) 2.8-3.2V
Pin3) 2.8-3.2V
Pin4) 0
Pin5) 4.75V
Pin6) 4.9V
Pin7) 5.2V
Pin8) 9.18V

2399
Pin1) 5V
Pin2) 2.4-2.5V
Pin3) 0
Pin4) 0
Pin5) 2.6V
Pin6 - Pin8) 0.7V
Pin9 - Pin16) 2.4-2.5V

Voltage converter seems to work correctly.

Any help is appreciated. Thanks.


Gonna triple check for solder bridges and component values today. Then, hook this up to a DC power supply and post new voltages.

Stand by...  8)
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Govmnt_Lacky on November 02, 2010, 09:18:15 AM
Ok... Some things to note about my build.
I used 100KB pots for both Speed and Depth.
I wired the Speed pot backwards (I used lugs 1 & 2 so when I go full CCW I get max speed)

New voltages (I think)

NE5532 (swapped out a new one)
Pin1) 2.7-3.2V (ONLY when Speed pot is at 0-20% rotation. Above 20% rotation, it is 0-1.4V)
Pin2) 2.7-3.2V
Pin3) 2.7-3.2V
Pin4) 0
Pin5) 4.7V
Pin6) 4.8V
Pin7) 5V
Pin8) 9V

2399
Pin1) 5V
Pin2) 2.45V
Pin3) 0
Pin4) 0
Pin5) 2.5V (DOES NOT LOOK RIGHT COMPARED TO nickd POST. SHOULDN'T IT BE 5V?)
Pin6) 0.7V (THIS LOOKS WRONG!)
Pin7) 0.7V
Pin8) 0.7V
Pin9-16) 2.5V

Voltage converter is good.

Checked for values and solder bridges. None to be found.

Things that look suspect to me are Pin 1 of the opamp and its relation to the Speed pot. Also, Pin 5 and Pin 6 of the PT2399.

Any help is appreciated. THANKS!
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: nick d on November 02, 2010, 10:46:09 AM
            Just checked my voltages on the working version - your 2399 is pretty well the same as mine , but your pin 1 ( my pin 7 ) is still off .
            Must be somewhere around the LFO ( only my humble noob guesswork ) . Keep on digging - its in there somewhere !
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: nick d on November 02, 2010, 11:01:07 AM
   The voltages I posted were for the non-working version . My pin 5 now shows 2.5 V , so all your 2399 voltages look OK . Still looks like the LFO area is the prime suspect .
    Where's Rick when we need him !   ( only joking ! )
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Govmnt_Lacky on November 02, 2010, 11:02:58 AM
   The voltages I posted were for the non-working version . My pin 5 now shows 2.5 V , so all your 2399 voltages look OK . Still looks like the LFO area is the prime suspect .
    Where's Rick when we need him !   ( only joking ! )

Do you still get the voltage change (2.5-3.5V) on Pin 6 of the 2399 like in your original post?
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Govmnt_Lacky on November 02, 2010, 11:22:21 AM
Wired up the Speed pot correctly (Lugs 2 & 3) and I still get the same outcome. Seems like I only get voltage wobble on Pin 1 of my 5532 if the Speed pot is at 80-100% of the pot rotation. Below 80% and the voltage lays at 0 and intermittently peak to ~1.5V!  ???

Also, I still only get 0.7V on Pin 6 of the 2399. Is that correct?

I read in past pages of this thread that some people have found that the 5532 only likes a 470K pot for Speed. Should I try a TL072 as the LFO?

Please help  :'(
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: nick d on November 02, 2010, 12:04:09 PM
    Just done a run-thro on my voltages .
                       PT2399
                                     1) 5.02 V
                                      2) 2.5 slight wobble
                                      3) 0V
                                      4) 0 V
                                      5)  2.22 - 2.5 V   (didn,t spot the small variation before )
                                       6)  0.75 V
                                       7)0.66 V
                                        8) 0.66 V
                                        9 - 16) As before

                       NE 5532   
                                           The only significant difference is pin 1 ( opamp LFO output - pin 7 on my layout )
                                              I have a varition from 1.4 - 7.4 ( lo-speed ) to 2.5 - 3.5 ( hi-speed )

                             

                                            Hope thats clarified the picture - that LFO voltage still looks way off , or is that a red herring ?
                                            Stick at it , you'll get there .
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Govmnt_Lacky on November 02, 2010, 12:12:50 PM

                       NE 5532   
                                           The only significant difference is pin 1 ( opamp LFO output - pin 7 on my layout )
                                              I have a varition from 1.4 - 7.4 ( lo-speed ) to 2.5 - 3.5 ( hi-speed )


Did you use the 470K for the Speed pot?
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Govmnt_Lacky on November 02, 2010, 01:07:08 PM
Used a DMM to check for solder bridges over ENTIRE circuit - NONE
Checked ALL component values against layout - ALL good except for using 100KB pot for Speed.
Swapped ICs - swapped both AND installed a TL072 for LFO.... no change.

Still getting the strange voltages on Pin 1 of the LFO. With the Speed pot set between 0-80%, I get intermittent voltages ranging from 0V to 1.5V (Sometimes I see larger values however, my DMM on "flashes" them and I can hardly read them fast enough.
When the Speed pot is set to 80-100%, I get a solid voltage swing from ~2.5 to 3.5V.

According to nick_d's input, when the Speed pot is CCW, I should get a solid voltage swing between ~1.4 to 7.4V.

Getting desperate  :-\
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: nick d on November 02, 2010, 01:44:35 PM
                  Looking at the speed pot on the schemo - you say 2.5 - 3.5 V at hi-speed , the lower end of the range seems to be where it goes wrong .
                  The unused pot connection - is it left open or tied to the wiper ? I tied mine to the wiper , after reading "The Secret Life of Pots ".
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: jable1066 on November 02, 2010, 01:49:15 PM
I am having the exact same problem! I'm getting all the voltages you are getting... I've done all the solder bridge checks, component values, wiring, orientation etc etc and I'm stumped if I know the answer. My voltages sway like yours do as well...
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Govmnt_Lacky on November 02, 2010, 01:55:42 PM
The unused pot connection - is it left open or tied to the wiper ? I tied mine to the wiper , after reading "The Secret Life of Pots ".

I left it open (Lug 1). I will try tying it to the wiper and report back the results. Cross your fingers please  :-X

EDIT: I am out of 100KB 9mm pots so I am going to have to use 100KA pots. I hope they work!!
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: jable1066 on November 02, 2010, 02:15:39 PM
Mine was also left open...
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Govmnt_Lacky on November 02, 2010, 02:23:52 PM
EPIC FAIL!!  >:(

I tied the open lug (Lug 1) to the wiper (Lug 2) on both pots and the voltages on Pin 1 of the LFO are STILL not right!

I am left with one final obvious option. Swapping the Speed pot for a 500KB. If that does not work it will have to sit on the shelf for a while because I honestly cannot think of anything else to try.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: nick d on November 02, 2010, 02:36:41 PM
            That's a bummer !   Running out of ideas here - it has to be around the LFO - if you are 100% sure there are no shorts , try searching for open circuits . Thats what I had on pin 6 , almost immpossible to see , found it after 3 days of hair-tearing ! DON'T LET IT BEAT YOU !
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Govmnt_Lacky on November 02, 2010, 02:54:59 PM
Thanks Nick. I am sure there are no shorts because:
1) I checked ALL AROUND the board traces with a DMM and found nothing.
2) I would think if it was shorted, I would get NO voltage.

As it stands now, it appears that I get the higher frequency LFO sweep (2.5 - 3.5V) but when I back the Speed pot down, my lower/wider sweep (1.4 - 7V) is non-exsistant!

I will have to plug it in tonight and see if any of my tinkering has changed anything. I also had a problem with the Depth pot and the fact that it appeared to have NO effect on the circuit.

I will post more info about what I found later tonight. Thanks for all the help nick  ;D
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Govmnt_Lacky on November 02, 2010, 06:46:50 PM
Just plugged my Little Angel in and it is still NOWHERE NEAR the "lushness" that I can hear on the sound clips! I am gonna try one more 2399 in the circuit and then it is off to the shelf cause I am out of ideas on this one  ???  >:(

HAS ANYONE GOTTEN THIS TO WORK WITH THE 100k POT FOR DEPTH INSTEAD OF 470/500K? 
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: nick d on November 02, 2010, 07:24:32 PM
                   Sorry to hear you've not had a good result on this , I know you put in a lot of time and effort . Just listened to those clips again - mine does not sound QUITE that good - that could be down to Tele Custom + VJ clone  v   my cheap SG clone + Kustom 10 W SS amp  , and of course my appalling guitar technique .
                     As regards the 100k/470k , minimum pot resistance = max depth , so should not be an issue ( I think ) .
                     Better luck next time !
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Pigyboy on November 03, 2010, 05:53:51 AM
Just plugged my Little Angel in and it is still NOWHERE NEAR the "lushness" that I can hear on the sound clips! I am gonna try one more 2399 in the circuit and then it is off to the shelf cause I am out of ideas on this one  ???  >:(

HAS ANYONE GOTTEN THIS TO WORK WITH THE 100k POT FOR DEPTH INSTEAD OF 470/500K? 

Hey Lackey,
Get your meter and check that the diagonal trace that runs beneath R20 & R16 is not shorting to the pad that connects R16 to C13 on the 1590A layout. I was checking the boards I made again for shorts and I found it shorted on one board.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Govmnt_Lacky on November 03, 2010, 10:55:57 AM
Get your meter and check that the diagonal trace that runs beneath R20 & R16 is not shorting to the pad that connects R16 to C13 on the 1590A layout.

Thanks Pigyboy. I checked that trace and it checked GOOD. I also ran over every trace again with the DMM and found no bridges. I checked component values again, all good. Looked over the offboard stuff, all good. I still have not tried a third PT chip so that is the last resort before scrapping and re-boarding.

For those of you joining late, I posted some voltages however, I have STILL NOT received any replys with voltages from a "known good" working unit. I have had a reply from nick_d but he even says that his Angel does not sound as lush as the sound clip from Rick.

It appears that the lo-speed setting on my Speed pot (higher resistance) is nonexistant. When I turn the Speed pot (100KB) all the way up I can get a subtle vibrato but that is only at the top of the rotation. MY Depth pot seems to have no effect at all.

I did put this on an oscope and I could see some signal change with adjustment of the Speed and Depth pot however, it was very... very small.

Basically, I need someone to post voltages of a good, working unit that sounds like Rick's sound clips.

Thanks a ton to all who have helped so far...  :)

Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: jable1066 on November 03, 2010, 12:13:58 PM
I know it doesn't help you much, but as I said before I'm having the exact same problem. The same is said about my speed pot - the only time I can get an effect is with full speed, full effect. I've posted somewhere else about voltages and emailed FC - the creator of the pedal and asked for his advice and voltages so I'll post them here when I'm done. I gave up on it today after wasting another few hours on it! Then I built an unsuccessful Bazz Fuzz - keeps getting a glitchy signal so I'm going to re-wire again. Here's a thought that just came to me actually... maybe you stripped off some excess stranded wire when stripping the covering off? I know I did with the Bazz Fuzz - which is probably why I get glitch signals. Try rewiring? I will do this at the weekend as I've probably wasted enough time on it for now - I'll let you know if it works for me.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Govmnt_Lacky on November 03, 2010, 12:34:33 PM
I know it doesn't help you much, but as I said before I'm having the exact same problem. The same is said about my speed pot - the only time I can get an effect is with full speed, full effect. I've posted somewhere else about voltages and emailed FC - the creator of the pedal and asked for his advice and voltages so I'll post them here when I'm done. I gave up on it today after wasting another few hours on it! Then I built an unsuccessful Bazz Fuzz - keeps getting a glitchy signal so I'm going to re-wire again. Here's a thought that just came to me actually... maybe you stripped off some excess stranded wire when stripping the covering off? I know I did with the Bazz Fuzz - which is probably why I get glitch signals. Try rewiring? I will do this at the weekend as I've probably wasted enough time on it for now - I'll let you know if it works for me.

Thanks jable. I would appreciate that if you get a response from FC or if you find an issue. As far as my Angel is concerned, my Depth pot is useless (to my ear) no matter what I do. My Speed pot ONLY changes the modulation when it is at 80-100% of the pot rotation and even then it just sounds like a subtle vibrato.
On a side note... the pedal does give a slight volume increase when engaged. And also, when I put a 440Hz/100mV square wave into the pedal, on the oscope I can see there are "spikes" that roll along the peaks that adjust with the pots. This is great but, it does NO GOOD if you cannot hear it through the amp  >:(
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: nick d on November 03, 2010, 02:16:38 PM
                  Hi , just read some recent posts re Little Angel . Having listened to the clips again and compared them to my results , I would like to chip in with a couple of observations.
                  Overall , the sound I get is pretty much the same ( making allowance for differences in guitar , amp , and playing technique ) . Having said that , there is one bit at about 0.50
                   that is quite noticeably different .
                   On the controls , depth does pretty well nothing below 70% , and at low speeds the effect is very subtle , but still noticeable compared to dry.
                   My overall impression is that I have built a worthwhile pedal . If you consider the simplicity of the circuit , and the fact that the 2399 was designed never intended
                   to be a chorus pedal , the end result , I think , pretty good .  I could probably spend a bit more money and buy a Behringer pedal that MIGHT sound a bit better
                   but that misses the point - we are DIY builders , trying out new ideas , and thats the way I like it .
                   ( STOP IT Nick , you are starting to preach ! )
                   

                   In conclusion , not perfect , not bad , on to the next one ! 
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Govmnt_Lacky on November 03, 2010, 02:35:30 PM
Thanks Nick. I just want mine to sound like the sound clip form Rick and no matter where I put the knobs and no matter what position they are in, I could not duplicate the lush tones that are on that clip. That is how I know something is wrong. It is not a matter of gear. The difference in that clip and what I hear goes way beyond gear setup.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: nick d on November 03, 2010, 03:19:24 PM
                  This has got me thinking ( a dangerous practice ! ) - component tolerances.....
                   The shorter delay , the better the chorus  - but the limit is 100R . So , if I use a resistor  , 5% , which is at the bottom of the range = 95R , and you happen to get
                  one thats 105R , my delay will be shorter and so sound better . This could happen by random chance , or by selection .
                   This would apply in any circuit where values are critical . So , by careful component selection or using trimmers , you can fine-tune the circuit .
                   This is a well-known idea , and could well be more trouble than its worth , but its worth bearing in mind . Hmmmmmmm.......       
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: frequencycentral on November 03, 2010, 03:28:41 PM
Here are voltages just taken from my Little Angel, which sounds the same as the breadboarded version I did you soundclips on. Speed at 3 o'clock, Depth at 12 o'clock:

NE5532

1:  0.13 to 4.9
2:  2.9 to 3.2
3:  2.7 to 3.1
4:  0v
5:  4.79
6.  4.9
7:  5.14
8:  9


PT2399

1:  5
2:  2.38 to 2.42
3:  0
4:  0
5:  2.75
6:  0.61
7:  0.88
8:  0.88
9 through to 16:  2.41 (slight movement)

It's pretty hard taking voltages from a moving LFO, guess accuracy depends on the resolution of the DMM, but you get the idea.

I really like mine. I have a half populated CE-2 PCB (3 times the size of the LA PCB!) which is looking sadly at me - it knows it isn't getting finished anytime soon now. Yeah, Little Angel isn't the best chorus you can build I'm sure. But it is the simplest. I dare anyone to design a lower parts count chorus.  :icon_biggrin:  I said early on in this thread that there would one day be an 'elite' version - that's still the plan, but the original Little Angel has always been a " how-few-parts-can-I-use-to-make-a-chorus?" concept.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: nick d on November 03, 2010, 03:31:32 PM
                  I could of course be talking total crap , but who knows ?
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Brymus on November 03, 2010, 04:22:14 PM
Did someone say Arch Angel ?   8)
The wait is agonizing...
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Govmnt_Lacky on November 03, 2010, 08:58:43 PM
Ok... I just swapped out the 2399 and there was NO CHANGE  >:(

Thanks for posting the voltages Rick but, I sadly admit defeat. Either this Little Angel I built is the most subtle chorus ever (does not even come close to sounding like your sound clip) or I need to just scrap this build and try again some other time. Now, I used 100K for both pots but.... when I set my pots to 3 oclock and 12 oclock as you said, my pedal sounds like nothing more than a VOLUME BOOSTER.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Earthscum on November 04, 2010, 01:03:30 AM
Hey, GL... try using a mixing mod on the output, either cut dry or cut wet, or maybe a blend pot between the two caps. I notice the effect more or less, depending on the blend. Also, I'm starting to think that the 100R from pin 6 may be small enough to show differences between chips, so you may be getting a bit less or more delay than others. On bass, I can say for sure that I needed a little more delay to get the lower notes to express properly.

And all of this effects how much of the LFO I hear. At shows, I usually have to run wet while I tune my LFO, then drop out the wet to my preferred level for that stage. At practice, I do the same thing, but that's just because I don't have a big enough STFU stick (drummers are annoyingly loud sometimes!)

So far, I'm totally happy with this, but I don't know how much I like the LFO part... but I can't come up with anything better myself, so I'm not complaining a bit.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Pakaloabob on November 04, 2010, 11:18:09 PM
A couple pages back I mentioned that my Little Angel build did not play well with my One Spot power supply but worked fine on battery.
I recently acquired a new power supply - Danelectro DA-1 that came free with a Vox V845 wah I got online (great deal BTW)
Little Angel likes the Danelectro power supply!
But again, if I try the One Spot, the circuit doesn't work. Hook up the Danelectro PSU again and wait a few minutes, success!
Has anyone else experienced, or heard of something like this? Should I open a new topic to fish for some comments?
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: nick d on November 04, 2010, 11:43:39 PM
               I got a Soundlab 450 , which will run 6 pedals with no problems . Puts out 8.6 V , not used any thing else apart from
           unregulated 9 V wall-warts , used on synth-type stuff with on-board 9-V  regulators . Never use batteries , 'cos I don't like them going flat on me .
            I've used Little Angel , BSIAB 2 , Phozer 2 , Tonebender , and others , never (touch wood !) had any problems .Am I just lucky or what ?
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Pigyboy on November 06, 2010, 03:03:21 PM
Video Demo of the Little Angel built by El Musico Loco.
Thanks for the great design Rick!
http://www.youtube.com/watch?v=oxyk3c9YXQM
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: azrael on November 07, 2010, 02:41:19 PM
Hm....This looks like a fun build. Anyone able to do a demo of it doing Paradise City chorus tone, or at least verify that it can do that?
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: radio on November 07, 2010, 03:52:13 PM
It surely! Thanks for the supplementary amount of motivation.

(I mean the sound sample  :D )

I got 2 PCB s on the way for this modulation effect.

If I should succeed with both ,I have one I ll try to tweak

a little bit.

Regards JM  :)
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Pigyboy on November 16, 2010, 03:38:00 AM
Hi everyone,
I think I stumbled onto something here. The first of these I built with a 5 volt L78L05 positive voltage regulators and all worked fine and then I built 2 with a L78L06 6 volt regulators. The first one started to work but then stopped and the PT2399's were getting hot but I didn't pay attention to it. I couldn't get it to work again so I built another and again it didn't work. I put in a 5 volt L78L05 this morning and it fired right up. I think this may be G-Lacky's problem so check it out if you are having problems.
Chris
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Govmnt_Lacky on November 16, 2010, 08:20:23 AM
Hi everyone,
I think I stumbled onto something here. The first of these I built with a 5 volt L78L05 positive voltage regulators and all worked fine and then I built 2 with a L78L06 6 volt regulators. The first one started to work but then stopped and the PT2399's were getting hot but I didn't pay attention to it. I couldn't get it to work again so I built another and again it didn't work. I put in a 5 volt L78L05 this morning and it fired right up. I think this may be G-Lacky's problem so check it out if you are having problems.
Chris


Sorry Chris.... I wish it was that easy over here. I just checked and the regulator is a KA78L05AZ from Fairchild and it is reading 5.01V on the output. I am going to check the "stupid" things again before I shelf this thing!  >:(
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Pigyboy on November 16, 2010, 09:01:12 AM
Hey Greg,
Check it all out again and feel the chip for heat. If it is getting hot at all swap the regulator. I would swap it out just to be sure and check your pinouts for the regulator just to be sure. Good Luck. This thing drove me crazy but it is great when it works.
Chris
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Govmnt_Lacky on November 16, 2010, 02:21:52 PM
This may be an odd request but....

Could someone post a picture of this chorus on an oscope? I set mine up as follows:

Frequency: 440Hz
Amplitude: 80mV
Wave: Square wave

I could really use a "working unit" to compare to.

When I engage the circuit, my square wave become more "sawtooth-like" with "spikes" in the middle of the peaks and valleys. These "spikes" never get larger or smaller however, they do change with the pots. When I turn the speed pot, the spikes move more rapidly/slowly back and forth along the peaks and valleys. When I adjust the depth pot, the "distance" in which the spikes travel along the peaks and valleys becomes longer or shorter.

Confirmation with a working unit on an oscope will give me a bit more sanity.  ;)
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: BoxOfSnoo on November 17, 2010, 09:01:48 AM
I wonder if a regeneration pot might be more useful as a sort of resonance control?

It's on my breadboard right now.  :D

How did this turn out, BTW? 

I just breadboarded mine, and it sounds good, but I'd like to give it a bit more "thickness".  It seems a little subtle to my ear, for some reason.  I already tried lowering R12 to 2K to try and get it slower.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Pigyboy on November 17, 2010, 09:10:19 AM
From looking at the datasheet I think you can manipulate the delay by changing R6. Yes ???
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: azrael on November 17, 2010, 12:16:43 PM
PigyBoy, how would you say this design is for hitting the "Paradise City" intro tone?
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Pigyboy on November 17, 2010, 01:17:08 PM
PigyBoy, how would you say this design is for hitting the "Paradise City" intro tone?
Hi Azrael,
Do you mean the 'bmwaaa-bb-bmwaaa-bb-bmwaaa-bmwaaa-bmwaaa' part at the start of the song?  ;D
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: azrael on November 17, 2010, 02:12:48 PM
Hmmm...wait, I'm evaluating your use of onomatopoeia..... :icon_lol:


Not how I would characterize it, but....I believe we're talking about the same thing? The very first guitar part of the song. :D
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: BoxOfSnoo on November 17, 2010, 08:43:40 PM
I wonder if a regeneration pot might be more useful as a sort of resonance control?

It's on my breadboard right now.  :D

How did this turn out, BTW? 

I just breadboarded mine, and it sounds good, but I'd like to give it a bit more "thickness".  It seems a little subtle to my ear, for some reason.  I already tried lowering R12 to 2K to try and get it slower.

Heh heh... Mr. DMM tells me that I needed to *RAISE* R12.  I changed it to 7.5K and it's pretty sweet about there.  The delay pot is handy just for tweaking that extra little bit of space in it.  Now if I can figure out how to give it a tiny bit of regen I'll be ready to perf this baby!
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Pigyboy on November 18, 2010, 03:29:05 AM
Hmmm...wait, I'm evaluating your use of onomatopoeia..... :icon_lol:


Not how I would characterize it, but....I believe we're talking about the same thing? The very first guitar part of the song. :D

I think you can get that tone with this box.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: kristoffereide on November 21, 2010, 04:09:52 PM
Anybody want to make me a board? Or tell me where I can order one with the info provided here?
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: frequencycentral on November 21, 2010, 04:18:39 PM
Anybody want to make me a board? Or tell me where I can order one with the info provided here?

Here: http://www.guitarpcb.com/apps/webstore/products/show/1690146
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Pigyboy on November 27, 2010, 04:48:45 AM
Has anyone seen the problem of the PT2399's latching up and not turning on the effect? I am not sure if this is due to a bad set of chips. I was using a 6 volt regulator and found the chip and the regulator getting hot so changed to a 5 volt regulator and it seemed to work but now I am getting reports that the same problem is intermittently re-occurring.
Any thoughts?
Thanks,
Chris
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: frequencycentral on November 27, 2010, 06:24:13 AM
Hmmm. I've read similar in one of the other recent PT2399 design threads. There could be a number of culpits:

Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Earthscum on November 27, 2010, 11:31:46 AM
That's the issue I came across with the Sewer Pipes. It wouldn't let me use anything less than 560R. When I would turn it on, I would get a small double-pop and then only the OP Amps would be working. I don't think I even hand anything coming out of the mod/demod sections. Even just setting up the chip for a normal datasheet delay yielded the same results. I swapped in other PT's and got the same thing, then I tried the ones from different source and they worked fine with the 100R.

The ones that don't like short delays are the ones I got from Tayda, but they are different than the first one I got from them. The 2 I originally used are from Steve (smallbear), and the first one I got from Tayda, and they have no problems with the 100R at all. The one from Steve have a nicer case, while the ones from Tayda look more like National chips... square, boxy, dull case. If I get a hankerin, I'll post pics of the different ones. Just gotta get into a case for a pic of one of them.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Pigyboy on November 27, 2010, 01:14:40 PM
^^^^
Thanks for the input FC &ES -
So in the end did they all work by raising the resistance to 560R?  Does it affect the effect?
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Earthscum on November 27, 2010, 01:33:07 PM
Ya know, I use a 10k pot with a 100R limit on mine, and I usually find it turned up to about 1.5-2.5k minimum for bass, so I don't think a 560 would make too much of a difference... maybe just a little bit of tone change.

I really wish they'd make a chip like the 2399 that does .1-5mS and 4-40ms or so. The 2399 effectively covers most of the longer range, and can easily do longer with multiples, but short delay lines are still kind of a pain.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: slacker on November 28, 2010, 05:20:10 AM
If you look at the latest datasheet it recommends not using less than 1k resistance off pin 6 at power on, the old ones never had this warning. http://www.princeton.com.tw/downloadprocess/downloadfile.asp?mydownload=PT2399_1.pdf (http://www.princeton.com.tw/downloadprocess/downloadfile.asp?mydownload=PT2399_1.pdf)

I think it depends on the individual chip as to whether it will work with less, I've got 2 Echo Bases both built with 3 year old PT2399s from Smallbear. The first one I built never has any problems no matter what the resistance is but the other one occasionally locks up if I turn it on with the delay time on minimum.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: frequencycentral on November 28, 2010, 06:51:53 AM
^^^

Thanks Ian, I hadn't seen that particular datasheet with the below 1K warning. The difference between 100R and 1K in terms of delay time is about 8ms. So I guess we say the value for R1 needs to be 1K to avoid lock-ups. Can anyone comment on the audible difference between 100R and 1K?
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Earthscum on November 28, 2010, 10:51:36 AM
Tonal difference is all I noticed, and it was slight. It definitely increases the perceived depth of the effect, IMO, but not bad. my Sewer Pipes is where I really noticed tonal change concerning the delay. Between about 220R and 1.2k there was more change, and after that the waves become too separated. I don't remember that much change in the LA...

The LFO section of my LA went kaput for some reason, or I'd just check it out for sure since I have the adjustable delay. If I get it working, I'll get back to ya.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Pigyboy on November 29, 2010, 03:39:26 AM
Thanks to you all for the new info. I will build another today and use the 1K and report back what happens.
cheers,
Chris
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Govmnt_Lacky on November 29, 2010, 09:42:31 AM
Thanks to you all for the new info. I will build another today and use the 1K and report back what happens.
cheers,
Chris

Definitely interested in your findings! Please let us know!  ;D
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: BoxOfSnoo on November 29, 2010, 01:36:25 PM
^^^

Thanks Ian, I hadn't seen that particular datasheet with the below 1K warning. The difference between 100R and 1K in terms of delay time is about 8ms. So I guess we say the value for R1 needs to be 1K to avoid lock-ups. Can anyone comment on the audible difference between 100R and 1K?

I tried it on my breadboard... you can kinda hear that it's doubling, though just barely.  My circuit seems to work with a 100R, but I also added a delay time pot as well for longer delays.

If your PT2399 won't work with 100R you can still get a decent sound out of it with 1K, but it will be different.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: tyronethebig on December 02, 2010, 12:03:56 PM
Just finished this with the 1590 layout! Had a problem (small bridge between pin 5'n'6 of IC2) but it was an easy fix and now it sounds great! Thanks Rick for the killer pedal!! Hopefully someday I'll be able to contribute with a sweet design of my own. Pics as soon as the enclosure actually gets here  8)
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: tyronethebig on December 02, 2010, 02:06:26 PM
Le sigh, I walked away to eat lunch and when I come back it doesnt work?

Ne5523 - Very close to ricks readings

PT2399
1-5.01v
2-2.32-2.42
3-0
4-0
5-5.01
6-.58
7-0
8-4.58
9- 4.84
10-.35
11 thru rest 2.41

*frustrated*
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: frequencycentral on December 02, 2010, 02:09:08 PM
Sounds like the PT2399 has locked up. Switch it off and on again and it'll probably work. Also try a 1k resistor for R1 instead of 100R.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: tyronethebig on December 02, 2010, 02:27:48 PM
It worked! Kinda :)

I turned it off and on and the effect came on, I then soldered in the 1k at R1 and its back to not working city. With a voltage readout similar to the one I described.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: tyronethebig on December 02, 2010, 02:32:25 PM
I spoke too soon, it works now.
Right before it kicked in the modulation I very slightly turned down the voltage to the pedal. I read earlier in the thread that the "Onespot didn't play well" with this circuit. I wonder if thats my problem. Thanks for being quick on the draw rick, I'll play around with this until its stable.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Pakaloabob on December 03, 2010, 08:24:06 AM
Although it is an annoying problem I'm glad I am not the only one who has experienced the issue of the PT chip locking up. At least it is well documented in this thread so others will know to try other power sources. For me, the Danelectro power supply works well.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: tyronethebig on December 04, 2010, 03:21:43 AM
BTW - this sounds really cool distorted with both speed and depth around 8 and ripping tritones. really agressive. kinda like...a little demon  :icon_twisted:
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: jable1066 on December 05, 2010, 09:41:25 AM
Bahhhh I fixed the little bugger after having problems with it and it keeps like not working. I'll switch it off and on and it'll not work then after a while it will work. However, one thing I noticed which is definately the route of the problem (I think it'll be safe to assume it is anyway) is... my voltage regulator and PT2399 are getting MEGA hot. Anyone know why these could be getting hot? I don't have a 78L05 to hand... I only have a 7805 which is too huge to fit in my socket :( So I'll have to wait till tomorrow to go buy one from the electronics shop near my house. I've reflowed and cleaned up the board probably 4 or 5 times now, somehow without lifting traces but it probably can't go on for much longer...
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: GodSaveMetal on December 06, 2010, 04:39:40 PM
(http://img687.imageshack.us/img687/8623/littleangelchorus.jpg)

Must see the gut shots on this one! Absolutely beautiful!!

What are the level mix and delay pots?????
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Earthscum on December 06, 2010, 05:54:08 PM
Delay just gives me a range from the 100R to 10k. When I was breadboarding, I figured out that this circuit needs a little bit more delay for bass guitar. The mix pot is a 100k in series with the 10k wet side output resistor. When you increase the delay, it really starts to cut across the dry signal, and with bass, you don't want a full-out delay, or your guitarists start running all over you (gotta keep the punch and presence up so they actually sound like they might actually be playing in time  :icon_twisted: ).

Page 8 has the mods.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: GodSaveMetal on December 07, 2010, 04:48:17 PM
In these mod: the pots market for DELAY, MIX and LEVEL are the correct positions?

(http://img138.imageshack.us/img138/4184/littleangelchorusmodcir.jpg)
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: tuckster on December 08, 2010, 05:28:54 AM
Did someone say Arch Angel ?   8)
The wait is agonizing...

Hi Rick, something new about the arch angel?
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: GodSaveMetal on December 09, 2010, 07:34:33 AM
I´ve made a layout for the mod of this pedal; it is correct?

(http://img697.imageshack.us/img697/9370/littleangelchoruslayout.gif)
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: GodSaveMetal on December 10, 2010, 09:00:07 AM
UUUUPSS!!! some mistake; here are the correct layout, you see an error? please post it! thanks:
(http://img27.imageshack.us/img27/9370/littleangelchoruslayout.gif)
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Perrow on December 10, 2010, 02:41:31 PM
Have just looked at it, not really checked anything, but the value seems to be missing from the "Level" pot (in the BOM).

(and there seems to be an awful lot of white space, it'll never fit a 1590A  ;))
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: p_wats on December 10, 2010, 03:14:43 PM
Hey guys,

Any chance someone's got a working perf layout for this? I tried, but something's not right...I'll probably just grab a PCB from the guitarpcb.com sale, but It would be cool to be able to perf it too...
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: GodSaveMetal on December 10, 2010, 03:15:47 PM
In Perú there are no standar cases for FX you must make yours!!!!! I make the cases for tree dimencions: 10x12x5 cm; 8x12x5cm and 15x12x5cm These are the standar for me!!!!! when I finaly made the pedal I post the interior and the made of these mod for your pleasure!!!!! OK I forgot to put the value of this pot an here is the new layout; please a look ofr another error!!! tnaks a lot!:
(http://img696.imageshack.us/img696/9370/littleangelchoruslayout.gif)
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: frequencycentral on December 10, 2010, 03:34:32 PM
Hey guys,

Any chance someone's got a working perf layout for this? I tried, but something's not right...I'll probably just grab a PCB from the guitarpcb.com sale, but It would be cool to be able to perf it too...

A PCB layout IS a perf layout too.   ;)   Many of the PCB layouts I have posted I have actually built on perf.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Perrow on December 10, 2010, 04:24:25 PM
In Perú there are no standar cases for FX you must make yours!!!!! I make the cases for tree dimencions: 10x12x5 cm; 8x12x5cm and 15x12x5cm These are the standar for me!!!!! when I finaly made the pedal I post the interior and the made of these mod for your pleasure!!!!!

No offence meant. Would be lovely to see a enclosure building tutorial, I can get the materials, just don't know how to make them. Well searched the forum a bit and found links to two articles, more always welcome :)

ps. Documented the links on my enclosure tutorial (http://www.rumbust.net/tiki-index.php?page=Enclosure+Tutorials) page on my wiki.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: meffcio on December 10, 2010, 05:09:17 PM
In Perú there are no standar cases for FX you must make yours!!!!! I make the cases for tree dimencions: 10x12x5 cm; 8x12x5cm and 15x12x5cm These are the standar for me!!!!! when I finaly made the pedal I post the interior and the made of these mod for your pleasure!!!!! OK I forgot to put the value of this pot an here is the new layout; please a look ofr another error!!! tnaks a lot!:
(http://img696.imageshack.us/img696/9370/littleangelchoruslayout.gif)
I may be wrong, but I see no sense in those long traces leading to Speed pot. And not only them. But well, I'm not an expert, and I didn't create a single layout myself. Just wanted to share thoughts.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: p_wats on December 10, 2010, 05:52:57 PM
Hey guys,

Any chance someone's got a working perf layout for this? I tried, but something's not right...I'll probably just grab a PCB from the guitarpcb.com sale, but It would be cool to be able to perf it too...

A PCB layout IS a perf layout too.   ;)   Many of the PCB layouts I have posted I have actually built on perf.

Yeah, I'm usually able to work with the PCB, but the dual opamp is throwing me off here. That latest PCB layout (with the mods) is a bit easier to wrap my head around, so maybe I'll try that.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Perrow on December 11, 2010, 06:15:31 AM
I may be wrong, but I see no sense in those long traces leading to Speed pot. And not only them. But well, I'm not an expert, and I didn't create a single layout myself. Just wanted to share thoughts.

Yeah, as I look at it a little more, there's really a lot of lost space on that one. Move things around just a little in the top two rows and make them one. Remove the extra (ground loop inducing) ground connection (out -) and you save a column. Getting a little creative on that left side should allow you to get rid of another column.

At the bottom there's a lot of traces just to get the speed and depth connections up close. Feels unnecessary as other pot connections are all over the place (more or less). You could remove at least one row there.

But I'm just a compact design loving guy  :)
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: T-Flex on December 17, 2010, 08:54:14 PM
This was a fun build - sounds cool.  But i am a bit baffled as to why all my pin readings look good with the exception of pin 6 of the 2399 which is reading 2.2v.  This seems a bit high.  Any guesses as to why this might be?  I am running 9v directly to the +Vcc of the 5532 instead of 5v but it is rated for much higher so i dont think this would be a problem.
Thanks
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: frequencycentral on December 18, 2010, 06:27:14 AM
IIR 2.2v at pin 6 sounds about right assuming R1 has a value of 1K, but too high if R1 has a value of 100R. I think the voltage at pin 6 is entirely dependent on the value of R1.  Not sure what you mean about running 9v directly to the +Vcc of the 5532 instead of 5v, as this is how the circuit was designed in the first place.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: frequencycentral on December 20, 2010, 06:49:14 PM
Here's another (unverifed) layout, with onboard pots, designed to fit in a 1590B. You can either buy board mount pots, or solder resistor legs or solid core to standard pots. There should be space to 'lay down' all the electro caps so they don't foul the pots which will overhang the PCB. A LED resistor is included on the board. A few components have moved here and there. I've also change a few values: R1 is now 1K instead of 100R as some folks were finding the PT2399 locking up with the lower value; C1 and C3 are 0.1uF instead of 0.01uF. I've performed these changes to my Little Angel, 1K is cool with me, and (unless I'm imagining it) there's a little less hiss with the caps values. Finally, Slade built a Little Angel recently and used rev log pots, which he reported gave a nice even taper. I'd recommend the layout is checked against the schematic before etching/building as I am only human.

(http://dl.dropbox.com/u/967492/Little%20Angel%20OBP%20PCB.gif)

(http://dl.dropbox.com/u/967492/Little%20Angel%20OBP%20PnP.gif)
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: x3mgrifter on January 10, 2011, 01:32:18 PM
has the latest pcb of little angel been verified yet?
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: askwho69 on January 13, 2011, 09:53:45 AM
this is an excellent layout
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Valoosj on January 13, 2011, 10:23:23 AM
as I am only human.


I thought you were the perfborg from outer space  ;D
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Renegadrian on January 17, 2011, 06:55:28 PM
Finally built it!!! I used the vero you can find at page 19 or HERE (http://www.sabrodesign.com/wp-content/uploads/2010/10/Little-Angel.gif). Yeah I should have finished mine before, then this one came up so I just used that!
I really like the LA!!! Simple but charming, you cannot stop those arpeggios!!!
Also I made a simple DELAY MOD - just a 1k res from pin 6 that goes to a 25-50k linear pot (I guess 25 is the best value, but I have none of them handy ATM) at pin 1, pin 2 and 3 to ground. So when pot is at its min it's stock, else It can be a nice "slapback" fx or a good short delay, try like "every breath you take" with it!!! I love it!!! Gotta box it up!!! And try it with my bass too!!!
Thank you Rick!!!  ;D
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Renegadrian on January 18, 2011, 08:51:11 AM
Now I have a 20k linear for the delay - it works better than the 50k. Also subbed the 500k pot for a 100k as someone suggested. Now it would be fun to add a speed LED. How can it be added?!
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: frequencycentral on January 18, 2011, 12:15:59 PM
Hi Adriano, glad you like it. To add a rate LED, tap off from the output of the LFO opamp (via  resistor, 1k maybe). On the vero layout you used, that would be pin 7 of IC1. (On my PCB layouts it would be pin 2 of IC2).
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: dylar on January 20, 2011, 02:18:50 AM
Quick question:
I built a Little Angel using the vero layout http://www.sabrodesign.com/wp-content/uploads/2010/10/Little-Angel.gif (http://www.sabrodesign.com/wp-content/uploads/2010/10/Little-Angel.gif) and it worked fine for a minute, but then it stopped working altogether.
The only deviation I made from the original design was to use a 1n4007 diode instead of a 1n4001. Don't think this should matter, but maybe?
Voltages check out on the PT2399 except pin 5, which reads much lower than it should (about .5v instead of the 2.6 or so that it should be).
I have no idea what happened. Any guesses?
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Renegadrian on January 20, 2011, 08:54:39 AM
The diode is not mandatory, it's just for polarity protection - as you can see, it is just between positive and negative. maybe you put it backwards!? You can just get rid of it, it has no relation to the sound path.
I used that layout too - just a couple of changes like R5 position and so on, but yeah it should work - check 7805 orientation, and voltage at pin 5 (I got 4.9V from mine)
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: BoxOfSnoo on January 20, 2011, 11:54:33 AM
Quick question:
I built a Little Angel using the vero layout http://www.sabrodesign.com/wp-content/uploads/2010/10/Little-Angel.gif (http://www.sabrodesign.com/wp-content/uploads/2010/10/Little-Angel.gif) and it worked fine for a minute, but then it stopped working altogether.
The only deviation I made from the original design was to use a 1n4007 diode instead of a 1n4001. Don't think this should matter, but maybe?
Voltages check out on the PT2399 except pin 5, which reads much lower than it should (about .5v instead of the 2.6 or so that it should be).
I have no idea what happened. Any guesses?

You're possibly locking up the PT2399.  Note the layout just above - R1 is 1K and R8 on your layout is 100R.  Raise R8 (on your layout) to 1K.

Another quick test is to kill the power for a couple of seconds and then try again.  If it comes back then that's your problem.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: p_wats on January 27, 2011, 09:36:45 AM
I finally built one of these (on a board from gutiarpcb.com). Very subtle, but I like the thickening of the sound almost more than the outright chorus. Combine that with a delay pot instead of R1 (I used 25K, because I don't mind very dirty repeats) and it's a lot of fun.

Otherwise, I ditched the depth pot (jumpered the connection), as it's already subtle enough.

I also messed around with the value of R18 (a pot was suggested, but I found a really low value resistor was all I needed here).

I'm hoping to box it up tonight with a "Noise Ensemble" (another PT2399 circuit posted here recently). Woo!
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Gordo on January 27, 2011, 11:24:56 AM
I'm using a NE5532 dual opamp. I used a 470k because here in the UK that's what we use, 500k seemingly being a value available in the US but not here. 500k will work just fine.

Is that metric electronics vs US Imperial electronics? Or do we just have controls here that "go to 500..." :icon_wink:
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: p_wats on January 27, 2011, 07:25:03 PM
This is strange, but while I was messing around with mine today I swear I had it doing multpiple repeats. Then when I finished the soldering it was back to a single repeat.

Anyone else found that too or any ideas on how to keep the multiple repeats?
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: rmachado on February 07, 2011, 11:35:39 PM
Hello, someone can sell me 2 or 3 1590A?
I live in Brazil and has nowhere to buy here.
Thanks, sorry my english.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: bdevlin on February 08, 2011, 04:59:13 PM
Sounds like the PT2399 has locked up. Switch it off and on again and it'll probably work. Also try a 1k resistor for R1 instead of 100R.

What is the procedure to switch off and back on.  Are you just referring to removing power?
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: frequencycentral on February 08, 2011, 05:02:38 PM
Sounds like the PT2399 has locked up. Switch it off and on again and it'll probably work. Also try a 1k resistor for R1 instead of 100R.

What is the procedure to switch off and back on.  Are you just referring to removing power?

Yeah! For a couple of seconds.......
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: bdevlin on February 08, 2011, 05:17:03 PM
Sounds like the PT2399 has locked up. Switch it off and on again and it'll probably work. Also try a 1k resistor for R1 instead of 100R.

What is the procedure to switch off and back on.  Are you just referring to removing power?

Yeah! For a couple of seconds.......

Okay then.  Maybe we have some factual evidence to help some people with issues.  My chips from eBay do not work.  But I just popped in the chip out of my PT80 which came from SmallBear and it works.  Pin 5 on the Small Bear reads 2.4V but on the eBay chip (Raycon??) it reads 5v.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: bdevlin on February 09, 2011, 12:15:24 AM
And oddly enough, the eBay chips work in my PT80.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: p_wats on February 09, 2011, 09:43:58 AM
I definitely recommend trying several PT2399s. The first one I used didn't modulate that well, but the second was great!

Also, I found it very ditch R13 entirely, as it seems to increase the depth available---from drunken sailor warble to slight shimmer (FC, does that make sense?).

However, mine is a little noisy. Anyone else experience this?

Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: juansolo on February 09, 2011, 09:51:45 AM
I've had a batch of 3 PTs that dont modulate in a LA.  They do work in an Echobase, so a little swapping was required.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: bluesman1218 on February 09, 2011, 11:08:02 AM
So glad I found this thread! I perform as a solo acoustic act and love the chorus in my Fender Acoustasonic Jr, but don't use it for most gigs. Just bought a Fishman SA 220 and love it but have been looking for a Chorus pedal to add in. Gonna check my inventory and get this puppy built.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: bluesman1218 on February 09, 2011, 01:51:41 PM
Quick question:
I built a Little Angel using the vero layout http://www.sabrodesign.com/wp-content/uploads/2010/10/Little-Angel.gif (http://www.sabrodesign.com/wp-content/uploads/2010/10/Little-Angel.gif) and it worked fine for a minute, but then it stopped working altogether.
The only deviation I made from the original design was to use a 1n4007 diode instead of a 1n4001. Don't think this should matter, but maybe?
Voltages check out on the PT2399 except pin 5, which reads much lower than it should (about .5v instead of the 2.6 or so that it should be).
I have no idea what happened. Any guesses?

I found a few errors in the Parts List for the following: C6 & C8 should be 100nF/.1uF
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Renegadrian on February 09, 2011, 02:14:21 PM
I found a few errors in the Parts List for the following: C6 & C8 should be 100nF/.1uF

The original schem at the first page calls for  10nf, so it it correct. I used the same layout and it works fine.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: bdevlin on February 10, 2011, 05:10:34 PM
Concern so called Depth issues.  As an experiment I put a 50k trimpot in parallel with R13.  There are some interesting results as you lower the trimpot.  I also wired in a Mix pot off of R18 but as of now I find it seeming sort of redundant with the Depth control.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: rmachado on February 11, 2011, 01:24:46 AM
My little angel work.
Pedal simple with great sound.
I put a 1k pot in place of the 100R resistor to control the delay time, did not see much difference, tomorrow replace for a pot of 10k. (any ideas??)
Now I need to get a cabinet.
Thanks to all who participated in this project.
Sorry my english.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: rmachado on February 11, 2011, 01:44:24 AM
Does it matter if I use all of cps of 100nF ceramic?
The polyester caps are very large.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Perrow on February 11, 2011, 01:54:09 AM
Does it matter if I use all of cps of 100nF ceramic?
The polyester caps are very large.

You should be ok, as long as you don't care about the cork-sniffers frowning at you. When that happens give them this link (http://www.diystompboxes.com/smfforum/index.php?topic=36392.msg762125#msg762125) and tell them those shells were used hunting their kind.

Although to be fair, there are times when ceramic versus film will change the sound of a circuit, not always for the worse though.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Renegadrian on February 11, 2011, 06:41:41 AM
All the caps I used are ceramics! it works so good! I have a 20k linear pot for the delay with a 1k in series (so when the pot is at 0 the minimum value is still 1k)
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Pigyboy on February 11, 2011, 07:44:25 AM
I'm not a cork sniffer but I do think using ceramic caps make the circuit have a lot of hiss. At least it did in the last one I built. I had used all film caps in the others and the latest seems more hissy with the ceramics. I did have to change the amp I test my stuff thru as the Peavey Classic 50 went back to our practice studio and now now I am using a Marshall Artist 30 tube amp to test at home. I would like to know it anyone else has this experience with the hiss.
Cheers,
Chris
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: p_wats on February 11, 2011, 10:19:07 AM
I'm not a cork sniffer but I do think using ceramic caps make the circuit have a lot of hiss. At least it did in the last one I built. I had used all film caps in the others and the latest seems more hissy with the ceramics. I did have to change the amp I test my stuff thru as the Peavey Classic 50 went back to our practice studio and now now I am using a Marshall Artist 30 tube amp to test at home. I would like to know it anyone else has this experience with the hiss.
Cheers,
Chris

I've got hiss without the use of ceramic caps.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Pigyboy on February 11, 2011, 11:44:32 AM
I'm not a cork sniffer but I do think using ceramic caps make the circuit have a lot of hiss. At least it did in the last one I built. I had used all film caps in the others and the latest seems more hissy with the ceramics. I did have to change the amp I test my stuff thru as the Peavey Classic 50 went back to our practice studio and now now I am using a Marshall Artist 30 tube amp to test at home. I would like to know it anyone else has this experience with the hiss.
Cheers,
Chris

I've got hiss without the use of ceramic caps.
Hey P_wats
Try a different amp if you can. I built another Angel today with film caps for a present for someone and both it and the other I have with ceramics are totally silent when I run them thru a Behringer powered speaker I have here. I have never liked this Marshall Artist 30. It has always been very trebly and also I just noticed I can really hear the effect oscillating when I am not playing much more than through the PA speaker. I didn't have this problem with the Classic 50.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: davepedals on February 20, 2011, 10:24:25 PM
would some kind soul work out the caps part list for me in terms for big bear electronics? they use mf, pf - not uf or nf. i know i'll screw it up if i do it myself! thanks,
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: p_wats on February 20, 2011, 10:40:06 PM
would some kind soul work out the caps part list for me in terms for big bear electronics? they use mf, pf - not uf or nf. i know i'll screw it up if i do it myself! thanks,



http://www.justradios.com/uFnFpF.html (http://www.justradios.com/uFnFpF.html)
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: davepedals on February 20, 2011, 10:50:28 PM
fantastic...thanks!  so what caps should I use? ceramic, poly film, silver mica? any one of these quieter?  I cannot find a 470k pot at small bear, is 500k ok?
thanks!
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Hides-His-Eyes on February 21, 2011, 09:42:34 AM
a good start:

ceramic for anything small, poly film for anything over a nf, electrolytic for anything over 1uf
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Kearns892 on February 21, 2011, 05:30:38 PM
Dave, Small Bear lists many of their caps as mF. On their site, this designation means Micro-Farads; 10-6 farads. This is the same as the standard designation - µF. This causes some confusion as in the SI system, the prefix µ typically designates micro (10-6) whereas m designates milli (10-3), but Small Bear does not hold to this convention! On the Small Bear site mF is really µF: microfarads.

Note pF is picofarads and stands for 10-12 farads and nF is nanofarads and stands for 10-9 farads.

Hope this helps!
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: davepedals on February 21, 2011, 10:29:28 PM
ok thanks for that info!  i've found about 4 different images now for this chorus, some show the components a bit differently for the caps. is there a correct caps list anywhere? specifically I need to know which caps (and how many) are electrolytic.  also some images show a 470k pot, other's show both pots as 100k, this has me confused a bit.  does the pcb from tonepad come with parts list and parts placement printed on the board?

it's been awhile since i've done a build but in the past i've built at least 100 projects.  

many thanks!
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: BoxOfSnoo on February 22, 2011, 10:39:21 AM
ok thanks for that info!  i've found about 4 different images now for this chorus, some show the components a bit differently for the caps. is there a correct caps list anywhere? specifically I need to know which caps (and how many) are electrolytic.  also some images show a 470k pot, other's show both pots as 100k, this has me confused a bit.  does the pcb from tonepad come with parts list and parts placement printed on the board?

it's been awhile since i've done a build but in the past i've built at least 100 projects.  

The two 10uF capacitors, the 100uF and the 47uF are electrolytic.  You can tell on the schematic in the first post, the ones that are polarized are the electrolytic ones.  You should always use the schematic as the definitive source for information, rather than relying solely on a layout  it will help you considerably in the future!  Use layouts more for parts location rather than parts identification.

However, a good verified layout is valuable.  check this post out: http://www.diystompboxes.com/smfforum/index.php?topic=86297.msg723128#msg723128 the round purple ones are electrolytic.

There was a discussion earlier on about the 470k pot (or 500k) where many found that a 100K would perform just as well, and make more difference over its whole travel.  The 500K in its higher resistance ranges was more like doubling rather than a separated chorusy sound.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Barcode80 on February 22, 2011, 07:10:21 PM
ok thanks for that info!  i've found about 4 different images now for this chorus, some show the components a bit differently for the caps. is there a correct caps list anywhere? specifically I need to know which caps (and how many) are electrolytic.  also some images show a 470k pot, other's show both pots as 100k, this has me confused a bit.  does the pcb from tonepad come with parts list and parts placement printed on the board?

it's been awhile since i've done a build but in the past i've built at least 100 projects.  

many thanks!
I don't know of a Tonepad project for this... ???
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: frequencycentral on February 22, 2011, 07:14:58 PM
ok thanks for that info!  i've found about 4 different images now for this chorus, some show the components a bit differently for the caps. is there a correct caps list anywhere? specifically I need to know which caps (and how many) are electrolytic.  also some images show a 470k pot, other's show both pots as 100k, this has me confused a bit.  does the pcb from tonepad come with parts list and parts placement printed on the board?

it's been awhile since i've done a build but in the past i've built at least 100 projects.  

many thanks!
I don't know of a Tonepad project for this... ???

Neither do I. I think he means guitarpcb.com, who no longer stock it.

BTW, when Slade built an Angel he used rev log for both pots and reported a nice even taper.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: davepedals on February 23, 2011, 12:45:05 AM
yes i meant guitarpcb.com. too bad they no longer offer it! thanks for all the info!
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: edukdu on February 25, 2011, 11:31:45 PM
Hey guys...greetings from brazil...

First of all...Congratulation on the schematic, Rick...my new favorite box...

Now...i was wondering if its possible to add a rate led to pin 6 of PT, for delay mod...

thanks again for this wonderfull little box...

Edu Gomes
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: askwho69 on February 26, 2011, 12:00:20 AM
Hi rick and everyone! i would like to build this box :D but one more question has anyone tried it with high gain? is it quite?  because robote delay is very noisy :(
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Barcode80 on February 28, 2011, 12:47:35 PM
Hi rick and everyone! i would like to build this box :D but one more question has anyone tried it with high gain? is it quite?  because robote delay is very noisy :(

You may have a problem with your build. Mine is quiet as a mouse. It doesn't get any noise except on the longest delay times.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: askwho69 on February 28, 2011, 08:47:24 PM
mmmhhh maybe ... it hizz like cracking! try to figure itout
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Xide88 on March 01, 2011, 03:40:09 PM
Holy ###t!!!! this pedal is amazing!!!!

Rick, thanks a lot for this chorus!!!!!  :)

Спасибо огромное!  ;)
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: frequencycentral on March 01, 2011, 07:29:05 PM
Holy ###t!!!! this pedal is amazing!!!!

Rick, thanks a lot for this chorus!!!!!  :)

Спасибо огромное!  ;)

Your welcome!
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: bluesman1218 on March 01, 2011, 11:34:16 PM
Did the vero board build and I have a ton of crackling. So much that I can't hear the chorus effect. VCC voltage is 4.97 on PT2399 and 5.4 on NE5532. I had the rate LED wired and it worked intermittently, but disconnected it. I'll hook it back up when the pedal is working. I'm not a circuit guy, just a builder, so if anyone has any suggestions, I would really appreciate it.

All solder joints are good, no bridging to adjacent traces, all trace cuts are clean and non-conductive, no components touching ground that shouldn't be grounded. I have swapped both chips and it's the same problem with all of them.

BTW, I got the last 2 boards from GuitarPCB and they'll be here soon. I will probably do a fresh build on them.

Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Govmnt_Lacky on March 02, 2011, 08:19:52 AM
VCC voltage is 4.97 on PT2399 and 5.4 on NE5532.

This does not look correct. You should have about 9V at Pin 8 of your 5532.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: bluesman1218 on March 02, 2011, 02:03:45 PM
VCC voltage is 4.97 on PT2399 and 5.4 on NE5532.

This does not look correct. You should have about 9V at Pin 8 of your 5532.

Correction - 8.65v at pin 8 of 5532 and 8.64v at Q1

Are there other readings I should be looking at?

Thanks for bearing with me.
Steve

BTW, here's a pic of the enclosure. Quickie paint job and decal for the alpha build.
(http://i83.photobucket.com/albums/j310/bluesman1218/Vintage%20Tone%20Amps/AngelChorusEnclosure.jpg)
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Govmnt_Lacky on March 02, 2011, 04:12:21 PM
Recommend you follow this link:

http://www.diystompboxes.com/smfforum/index.php?topic=29816.0

Repost after reading through the link and following what it says. You will get it fixed 10x faster!

Good Luck  ;D

Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: bluesman1218 on March 03, 2011, 09:31:38 AM
Recommend you follow this link:

http://www.diystompboxes.com/smfforum/index.php?topic=29816.0

Repost after reading through the link and following what it says. You will get it fixed 10x faster!

Good Luck  ;D



Thanks, GL. I printed and read through the debugging pages (helped me eliminate DC hum), but didn't see this one. I'll go through RG's steps and take it from there. He is such a terrific resource to all of us hobbyists.
Title: Need some Debugging help on "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: bluesman1218 on March 03, 2011, 05:21:00 PM
RG Keen Debugging checklist

1.What does it do, not do, and sound like?  Constant crackling and can’t hear effect. When turned off (true bypass) all is well, so I don't think it's an off-board wiring issue.

2.Name of the circuit = Little Angel Chorus (VERO layout)

3.Source of the circuit (URL of schematic or project) = Vero Layout I used http://www.diystompboxes.com/smfforum/index.php?topic=86297.msg737758#msg737758  (http://www.diystompboxes.com/smfforum/index.php?topic=86297.msg737758#msg737758)
Original layout/parts list http://www.diystompboxes.com/smfforum/index.php?topic=86297.msg723128#msg723128 (http://www.diystompboxes.com/smfforum/index.php?topic=86297.msg723128#msg723128)

4.Any modifications to the circuit? N

5.Any parts substitutions? If yes, list them. no.

6.Positive ground to negative ground conversion?  Don’t know

Voltage readings
Voltage at the circuit board end of the red battery lead = 8.34
Voltage at the circuit board end of the black battery lead = 0

Q1   78L05   
Out = 4.97   
In =   7.94   
Grnd =0.01

IC1 NE5332
P1   0   P4   0.01           P7   varies   
P2   3.35   P5   varies   P8   8.20   
P3   2.93   P6   varies         

IC2 PT2399
P1   4.97   P4   0.01   P7   3.23   P10   2.48   P13   2.48   P16   0.01
P2   2.47   P5   0.95   P8   3.28   P11   2.48   P14   2.48   P17
P3   0.01   P6   2.32   P9   0.27   P12   2.10   P15   0.08   P18

Z1 (zener)
A (anode, the non-band end) =   0.01
K (cathode, the banded end) =   8.12

Voltage on all Electrolytic caps is higher on (+) pin than on (-) pin

I have PCBs coming and will do a fresh build on them. Until then, I would love to get this working. Any help would be greatly appreciated, as I'm not a circuit design guy, but can follow directions and build.

Steve
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Pigyboy on March 03, 2011, 05:49:11 PM
Can you post a pic of the board and the inside of the build?
Chris
Title: Re: Need some Debugging help on "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Renegadrian on March 03, 2011, 06:32:28 PM
5.Any parts substitutions? If yes, list them. Vero listed 7 – 100nF caps. Since this count/value didn’t match Rick’s original, I used .1uF values.

Really?!? Now THAT'S the reason it doesn't work! lucky you it didn't explode...why did you use .1µ instead of the 100n!!!
That can be dangerous...I warned you.
Title: Re: Need some Debugging help on "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: bluesman1218 on March 03, 2011, 06:52:12 PM
5.Any parts substitutions? If yes, list them. Vero listed 7 – 100nF caps. Since this count/value didn’t match Rick’s original, I used .1uF values.

Really?!? Now THAT'S the reason it doesn't work! lucky you it didn't explode...why did you use .1µ instead of the 100n!!!
That can be dangerous...I warned you.

As I said, I'm not a circuit guy and unless the circuit was changed for the vero layout, I didn't understand why the values would differ from Rick's original circuit. If I'm missing something, please let me know.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Taylor on March 03, 2011, 07:03:03 PM
Bluesman, he's just messing with you (a rite of passage, but perhaps a little unfair).

.1uf (also written .1µ or rarely .1mf) is the same value as 100nf.

This page will help you get familiar with the conversion between uf, nf, and pf. Luckily it a base 10, metric thing, so it's pretty logical and simple once you get used to it.

http://www.justradios.com/uFnFpF.html
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: bluesman1218 on March 03, 2011, 08:38:45 PM
Bluesman, he's just messing with you (a rite of passage, but perhaps a little unfair).

.1uf (also written .1µ or rarely .1mf) is the same value as 100nf.

This page will help you get familiar with the conversion between uf, nf, and pf. Luckily it a base 10, metric thing, so it's pretty logical and simple once you get used to it.

http://www.justradios.com/uFnFpF.html

Thanks, Taylor, I had a brain fart. All values are correct and I have fixed the original request above.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: bluesman1218 on March 03, 2011, 09:14:04 PM
Can you post a pic of the board and the inside of the build?
Chris

Here's a shot of the board with the same orientation as the vero layout diagram. I'm not really happy with it, but  I would like to get it working. BTW, the LED is disconnected temporarily, hence the loose yellow wire.
(http://i83.photobucket.com/albums/j310/bluesman1218/Vintage%20Tone%20Amps/AngelChorusInterior.jpg)


BTW, I made this cable so I don't have to keep hooking up the batttery in the pedal. It's also a handy backup on stage if you use batteries when performing live and one fails.
(http://i83.photobucket.com/albums/j310/bluesman1218/Vintage%20Tone%20Amps/9vAdapter.jpg)
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Renegadrian on March 04, 2011, 07:23:02 AM
+1 on the battery cable! I have several of them.
The pic of the board doesn't help, it looks like the vero layout but how can we see if there is something wrong?!
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Govmnt_Lacky on March 04, 2011, 08:26:42 AM
I dont have my numbers handy HOWEVER,

A few things stick out to me. Particularly your voltages on IC1 Pin 1 and IC2 Pins 15 & 16.

You may want to construct an AUDIO PROBE and use it to track down some of your problems. Just go to the search function above and search for "Audio Probe." Its a simple item to construct and is invaluable in troubleshooting.

Good Luck  ;D
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: bluesman1218 on March 04, 2011, 08:38:24 AM
+1 on the battery cable! I have several of them.
The pic of the board doesn't help, it looks like the vero layout but how can we see if there is something wrong?!


Re: cable - I always stock the hard plastic 9v snaps instead of the ones that bend and break from repeat use.
Re: pic - I just right click on it, <Copy Image> and paste it to MS Photo Editor to enlarge and scroll. I'll see if Photobucket has a way to show a larger one if you click on it.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: bluesman1218 on March 04, 2011, 08:41:55 AM
I dont have my numbers handy HOWEVER,

A few things stick out to me. Particularly your voltages on IC1 Pin 1 and IC2 Pins 15 & 16.

You may want to construct an AUDIO PROBE and use it to track down some of your problems. Just go to the search function above and search for "Audio Probe." Its a simple item to construct and is invaluable in troubleshooting.

Good Luck  ;D

Thanks, GL.

I just built one the other day and will give it a shot. Should I trace from the ICs using those pins as starting points? Sorry for the question, but even though I don't follow circuits, I'm good at following directions and eventually it sinks in.

Steve
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Govmnt_Lacky on March 04, 2011, 09:24:37 AM
Should I trace from the ICs using those pins as starting points?

Just start with the probe at the circuit's audio input and use the layout/schematic to follow the audio flow through the circuit. It is not ALWAYS going to sound loud and perfect however, as long as you are getting SOME SOUND you can be fairly confident that it is OK.

If you run into something that does not look or sound right, just create a new thread particular to your build and list all of the items from the debug thread that I referenced earlier + your questionable audio probe results. You will get lots of help as long as you follow these two rules:

1) You use the debug thread
2) You put some effort into finding the error/problem.

Good Luck  ;D
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: bluesman1218 on March 04, 2011, 09:33:08 AM
Should I trace from the ICs using those pins as starting points?

Just start with the probe at the circuit's audio input and use the layout/schematic to follow the audio flow through the circuit. It is not ALWAYS going to sound loud and perfect however, as long as you are getting SOME SOUND you can be fairly confident that it is OK.

If you run into something that does not look or sound right, just create a new thread particular to your build and list all of the items from the debug thread that I referenced earlier + your questionable audio probe results. You will get lots of help as long as you follow these two rules:

1) You use the debug thread
2) You put some effort into finding the error/problem.

Good Luck  ;D

Thanks, that's my goal.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: bdevlin on March 05, 2011, 11:57:33 PM
My Little Angel seems to have Speed and Depth controls that both can adjust speed depending on where they are set.  The only changes I have to the "official" circuit are the Mix control at R18 AND....I put a 50k trimpot in parallel with R13 that effectively reduces R13.  Wondering if that is why I am getting my results.  I can't help but notic that lug 2 of Depth and lug 3 of Speed are only separated by C10.  Any thoughts???
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: gopher on March 06, 2011, 10:00:12 AM
Bluesman,
I am a new member but I was just scanning the posts on this project. 

Thought I would let you know the following...
I just had some similar trouble in a project that used an NE5532 on a 9 volt supply. The Texas Instruments datasheet says this opAmp needs a 10volt supply minimum (+/- 5 volts). Other manufacturers (OnSemiconductor) lists +/-3 volts. Out of 12 chips, I found 2 TI chips that didn't work on a 9 volt supply. When I used a 9 volt battery giving only 8.4 volts, 2 more showed limited function. 

http://focus.ti.com/lit/ds/symlink/ne5532.pdf

http://www.onsemi.com/PowerSolutions/product.do?id=NE5532

-gopher
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: bdevlin on March 06, 2011, 02:30:17 PM
Never mind my last post....user error.  I will toss in however that I give a thumbs down to the Delay mod.  Unless you do not have a delay pedal and want some slapback.  Otherwise, if you want a Chorus pedal stick to the basic layout.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: bluesman1218 on March 07, 2011, 10:15:43 PM
OK, so I did a fresh build on a PCB and it worked right off the bat. Very cool. Now I have to re-read the thread for some fine tuning. I don't have a whole lot of depth or usable speed. I have tried 2 of my 3 PT2339 chips. I think there were some posts about this, now to find them.

I'm guessing the problem in my vero build was the traces and/or micro solder bridge(s). I'm much happier with the PCB build and will probably stick to PCBs in the future.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Renegadrian on March 08, 2011, 06:56:47 AM
Man, don't give up on vero! I am so fond of it...the quickest way to build for me...Glad you made it with the LA.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Govmnt_Lacky on March 08, 2011, 07:56:01 AM
I don't have a whole lot of depth or usable speed. I have tried 2 of my 3 PT2339 chips. I think there were some posts about this, now to find them.

I built mine with 100K pots in BOTH positions and I am in agreement with you. When I first fired it up, I was kinda disappointed. It did not have much Depth at all and the Speed was something to be desired. Then I talked to another forumite and he told me that this is a fantastic Chorus to use for playing single note phrases or leads... HE was right! This is not going to sound like a CE-2 or Small Clone if that is what you are looking for. But it really fattens up and puts a great "voicing" on single note playing!  ;D
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: bluesman1218 on March 08, 2011, 08:27:34 AM
Man, don't give up on vero! I am so fond of it...the quickest way to build for me...Glad you made it with the LA.


I have plenty of boards and I'll likely use them. In all honesty, part of the problem was the iron I was using. Pulled an old one out and much better results. This was also my first time with vero. I'll build a few simpler circuits and get the hang of it. It just seems a bit limiting on layout when trying to keep a small footprint.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: bluesman1218 on March 08, 2011, 08:30:57 AM
I don't have a whole lot of depth or usable speed. I have tried 2 of my 3 PT2339 chips. I think there were some posts about this, now to find them.

I built mine with 100K pots in BOTH positions and I am in agreement with you. When I first fired it up, I was kinda disappointed. It did not have much Depth at all and the Speed was something to be desired. Then I talked to another forumite and he told me that this is a fantastic Chorus to use for playing single note phrases or leads... HE was right! This is not going to sound like a CE-2 or Small Clone if that is what you are looking for. But it really fattens up and puts a great "voicing" on single note playing!  ;D

I'm just using it to thicken my sound on my solo acoustic rig and from the clips I've heard, it's exactly what I'm looking for. In all fairness, I think my speed pot may be audio taper (had it in inventory) and that may be the problem. I'm ordering parts for inventory and I'll check that first.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: BoxOfSnoo on March 08, 2011, 11:23:09 AM
Never mind my last post....user error.  I will toss in however that I give a thumbs down to the Delay mod.  Unless you do not have a delay pedal and want some slapback.  Otherwise, if you want a Chorus pedal stick to the basic layout.

I'd say definitely otherwise, it's definitely not a delay replacement!  Just give it a tiny bit of delay and it widens the sound considerably.  I put a 5k pot in and that's loads of delay for this purpose - I  usually have it only cracked open about 20% or so.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Renegadrian on March 08, 2011, 12:01:26 PM
It just seems a bit limiting on layout when trying to keep a small footprint.

Really?! Let me firmly disagree on this one...my layouts prove it.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: bluesman1218 on March 08, 2011, 12:34:23 PM
It just seems a bit limiting on layout when trying to keep a small footprint.

Really?! Let me firmly disagree on this one...my layouts prove it.

I'm definitely open. Do you have some layout samples you'd be willing to share. Admittedly, layout is a weak spot for me.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Renegadrian on March 08, 2011, 02:35:44 PM
Steve, just check my directory in the gallery!  :icon_wink:
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: bluesman1218 on March 08, 2011, 02:47:31 PM
Steve, just check my directory in the gallery!  :icon_wink:

Got it, Adriano! Still learning my way around here. Gracie!
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: bluesman1218 on March 09, 2011, 05:33:40 PM
IT"S.... A.... LIIIIIIVE!! Rick had me check R7, and it was way off (used my good DMM this time). Replaced it and my voltages were in line, but still no chorus. As a last resort, I cleaned/touched up all my solder joints and now it works! I still want to get more effect at 12 o'clock with both pots, but I'm so pysched that I have chorus.

Think I'll invest in a better soldering station. Circuit Specialists has a real nice one for $30. Thanks to Rick, Pigyboy, Government Lackey, and Chris for all your help.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: frequencycentral on March 09, 2011, 05:45:11 PM
IT"S.... A.... LIIIIIIVE!! Rick had me check R7, and it was way off (used my good DMM this time). Replaced it and my voltages were in line, but still no chorus. As a last resort, I cleaned/touched up all my solder joints and now it works! I still want to get more effect at 12 o'clock with both pots, but I'm so pysched that I have chorus.

Think I'll invest in a better soldering station. Circuit Specialists has a real nice one for $30. Thanks to Rick, Pigyboy, Government Lackey, and Chris for all your help.

 :icon_biggrin:  :-*
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Pigyboy on March 09, 2011, 06:43:46 PM
IT"S.... A.... LIIIIIIVE!! Rick had me check R7, and it was way off (used my good DMM this time). Replaced it and my voltages were in line, but still no chorus. As a last resort, I cleaned/touched up all my solder joints and now it works! I still want to get more effect at 12 o'clock with both pots, but I'm so pysched that I have chorus.

Think I'll invest in a better soldering station. Circuit Specialists has a real nice one for $30. Thanks to Rick, Pigyboy, Government Lackey, and Chris for all your help.
WooHoo!
Hats off to Mr. Holt!
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: GodSaveMetal on March 15, 2011, 05:17:18 PM
Here's mine:
(http://img687.imageshack.us/img687/3817/tomatripascercadetallep.jpg)
The L7805 it's too big I change it by the 78L05 tiny one!!
There is a detail of the pot PCB:
(http://img143.imageshack.us/img143/3406/tomaladosoldaduraydetal.jpg)
I made this in all of my pedals!!!!!
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: LaceSensor on March 16, 2011, 05:06:23 PM
I just built one of these on vero and I have it hooked up without a footswitch and I get sound through, only issue is its just my clean sound.

Any ideas on what to do next? I am newbie to troubleshooting and Im not sure how to measure the voltages across the ICs :(

Thanks for your help and patience...
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: frequencycentral on March 16, 2011, 06:58:54 PM
I am newbie to troubleshooting and Im not sure how to measure the voltages across the ICs :(

Got a DMM (multimeter)? Hook up the black probe to ground, then use the red probe to check the voltage of each pin of both chips.

This thread is your best friend: http://www.diystompboxes.com/smfforum/index.php?topic=29816.0
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: LaceSensor on March 16, 2011, 07:16:44 PM
Hi

I got 0 when I tried that so figured Id done something wrong :S

Sorry for the newbness and thanks for your reply.

Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: LaceSensor on March 16, 2011, 07:52:11 PM
I think Im just gonna rebuild this from scratch.
I cant figure out what I did wrong, and I have made other pedals successfully  :icon_redface:
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: GodSaveMetal on March 16, 2011, 08:10:44 PM
I have a problem with the PT2399 it sens probably sensitive to statics; some of the IC's I tried do not make the effect; and others make the effect in some level; some high and others a bit low!!!!! I've lucky with the first it's loud; and I prove a second one no effect; others less or more effect!!!!! that would be happends!!!! do anybody have this problems????
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: ronnie on March 17, 2011, 09:45:12 AM
In Perú there are no standar cases for FX you must make yours!!!!! I make the cases for tree dimencions: 10x12x5 cm; 8x12x5cm and 15x12x5cm These are the standar for me!!!!! when I finaly made the pedal I post the interior and the made of these mod for your pleasure!!!!! OK I forgot to put the value of this pot an here is the new layout; please a look ofr another error!!! tnaks a lot!:
(http://img696.imageshack.us/img696/9370/littleangelchoruslayout.gif)
I may be wrong, but I see no sense in those long traces leading to Speed pot. And not only them. But well, I'm not an expert, and I didn't create a single layout myself. Just wanted to share thoughts.

Hi, is there a pcb for this layout with all the pots, I'd like to make this version,
I hope their is one, thanks for any help with this
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: GodSaveMetal on March 17, 2011, 09:58:32 AM
Yep I'm the author of that layout here.s the PCB:
(http://i.imgur.com/0Zfj3.jpg)
Just read the tread for further modifications!!!!
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: ronnie on March 17, 2011, 10:13:56 AM
Awesome man, thank you so much, did you build it yet with your pcb
Does everything work Ok
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Govmnt_Lacky on March 17, 2011, 10:20:55 AM
(http://img696.imageshack.us/img696/9370/littleangelchoruslayout.gif)

Another nice layout GSM. You might want to edit your Capacitor values as some of them look to be missing information OR are labeled wrong (pF instead of uF)
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: GodSaveMetal on March 17, 2011, 06:30:40 PM
Awesome man, thank you so much, did you build it yet with your PCB
Does everything work OK

I don't build this yet but is based on the idea of Earthscum!!!!!! but the version whit two potentiometers it's great; prove this a notice what happends!!!!!!!!!!!!
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: GodSaveMetal on March 17, 2011, 06:44:01 PM
Another oops!!!!! some tipping error labeled on C6 is 0.1uF the correction is in this layout:
(http://i.imgur.com/qGgJV.gif)
Thanks Govmnt_Lacky for your observations!!! something else please!!!!!
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: ppaappoo on March 19, 2011, 05:47:57 PM
Hi, i make the chorus but don't works, only sound the clean guitar. I used this PCB by Slade on page 8

(http://img210.imageshack.us/img210/6448/littleangelchoruspcblay.jpg)

This is may board

(http://s1d5.turboimagehost.com/t1/6497698_P1020015.JPG) (http://www.turboimagehost.com/p/6497698/P1020015.JPG.html) (http://s1d5.turboimagehost.com/t1/6497707_P1020016.JPG) (http://www.turboimagehost.com/p/6497707/P1020016.JPG.html)

And this are my values compared to the frecuency central ones.

Power supply 8.93V
Tester range 20VDC

TL072

1: 1.4 to 7.3
2: 2.7 to 3.3
3: 2.6 to 3.3
4: 0v
5: 4.79
6. 4.95
7: 4.95
8: 8.93


PT2399

1: 4.95
2: 2.2 to 2.5
3: 0
4: 0
5: 4.94
6: 0.55
7: 0
8: 4.55
9: 4.78
10: 0.33
11 through to 16:  2.4 (slight movement)

Frecuency central

NE5532

1:  0.13 to 4.9
2:  2.9 to 3.2
3:  2.7 to 3.1
4:  0v
5:  4.79
6.  4.9
7:  5.14
8:  9


PT2399

1:  5
2:  2.38 to 2.42
3:  0
4:  0
5:  2.75
6:  0.61
7:  0.88
8:  0.88
9 through to 16:  2.41 (slight movement)

Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Govmnt_Lacky on March 19, 2011, 06:50:35 PM
This is may board

(http://s1d5.turboimagehost.com/t1/6497707_P1020016.JPG) (http://www.turboimagehost.com/p/6497707/P1020016.JPG.html)

My advice would be to GET RID of that 100 ohm resistor off of Pin 6 of the PT2399 (the one between the 2399 and the voltage regulator) and replace it with a 1K ohm resistor. There has been discussion in this thread about the 100 ohm resistor causing problems.

Good Luck  ;D
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: GodSaveMetal on March 19, 2011, 07:30:24 PM
OK that's 100R resistor causes problems????? if i changes with the 1K you proposed will work fine????? I probe the original layout and changes the PT2399 and It's fine with the 100R resistor!!!! the IC will be that causes problem????? It is wright o no????
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Govmnt_Lacky on March 19, 2011, 07:40:56 PM
OK that's 100R resistor causes problems????? if i changes with the 1K you proposed will work fine????? I probe the original layout and changes the PT2399 and It's fine with the 100R resistor!!!! the IC will be that causes problem????? It is wright o no????

You need to go back and read Replys 435 through 450. Might clear it up for you.

Good Luck  ;D
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: bluesman1218 on March 19, 2011, 08:42:53 PM
Hi, i make the chorus but don't works, only sound the clean guitar.
And this are my values compared to the frecuency central ones.

Power supply 8.93V
Tester range 20VDC

TL072

1: 1.4 to 7.3
2: 2.7 to 3.3
3: 2.6 to 3.3
4: 0v
5: 4.79
6. 4.95
7: 4.95
8: 8.93


PT2399

1: 4.95
2: 2.2 to 2.5
3: 0
4: 0
5: 4.94
6: 0.55
7: 0
8: 4.55
9: 4.78
10: 0.33
11 through to 16:  2.4 (slight movement)

Frecuency central

NE5532

1:  0.13 to 4.9
2:  2.9 to 3.2
3:  2.7 to 3.1
4:  0v
5:  4.79
6.  4.9
7:  5.14
8:  9


PT2399

1:  5
2:  2.38 to 2.42
3:  0
4:  0
5:  2.75
6:  0.61
7:  0.88
8:  0.88
9 through to 16:  2.41 (slight movement)



I had a similar problem with my last build. Here's what it boiled down to for me -
1. make sure the 100R is 1k - it has to do with the PT2399 locking up
2. check the 330K behind the voltage regulator - mine drifted in value
3. check the 1meg from pin 7 on the opamp

In bypass. everything was fine, but no signal at all with the effect on. I found that when I touched the back of the PCB in the output path, I got hum .
I also a - touched up my solder connections
        b - checked every solder joint and trace for continuity and solder bridges
The end result was #3 above
#2 above took care of my voltage readings

Hope this helps. I was very pleased with the build once it was working.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: ppaappoo on March 19, 2011, 09:27:07 PM
i changed R1 (100R) to 1K and the effect becomes to work but the depth pot only acts at the end, i used a 470k one
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Govmnt_Lacky on March 19, 2011, 09:30:30 PM
i change R1 (100R) to 1K and the effect became work but the depth pot only acts at the end. i use a 470k one

This was also addressed in this thread. Some people (including me) opted to use a 100K pot because the effect was only working during the last little bit of the 470K pot rotation (the last 100K or so)
Rick however, voiced his opinion about this saying that he liked the "doubling" effect that the 470K pot gave when it was in use.
It is all in this thread.... just gotta find it.  ;)

Good to hear you got it working though  ;D
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: ppaappoo on March 19, 2011, 09:34:57 PM
yes, i'll change the depth pot and adjust R1 to my teste.

So, for the next builders:
DEPTH POT ---> 100k
R1 ---> 1k to 10k or 22k
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: GodSaveMetal on March 19, 2011, 09:48:15 PM
yes, I'll change the depth pot and adjust R1 to my taste.

So, for the next builders:
DEPTH POT ---> 100k
R1 ---> 1k to 10k or 22k
OK OK!!! that's fine are you sure for change the 100R for that's values??? what happends??? now your pedal is in functions???
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: ppaappoo on March 20, 2011, 02:17:11 AM
1K for R1 it's ok,you olso can use a 5k pot in series with 1k resistor to make a delay control.

the chorus works! thanks to all
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: ppaappoo on March 20, 2011, 02:53:43 PM
I have a question, what type of wave generated by lfo?
if someone had a function generator may inject a specific signal on pin 2 of the pt2399, and compare how respond the chorus.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: GodSaveMetal on March 20, 2011, 07:04:13 PM
1K for R1 it's ok,you olso can use a 5k pot in series with 1k resistor to make a delay control.

the chorus works! thanks to all
thank ppaappoo I made other PCB for probe this and other modes; my 5 pot mode!!!!!!!!!!!!
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: ppaappoo on March 21, 2011, 01:33:49 PM
today I will inject a triangular signal on pin 2 of pt2399, but I have a doubt about the voltage range supported by the ic.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: LaceSensor on March 22, 2011, 06:35:28 AM
Hi, i make the chorus but don't works, only sound the clean guitar.
And this are my values compared to the frecuency central ones.

Power supply 8.93V
Tester range 20VDC

TL072

1: 1.4 to 7.3
2: 2.7 to 3.3
3: 2.6 to 3.3
4: 0v
5: 4.79
6. 4.95
7: 4.95
8: 8.93


PT2399

1: 4.95
2: 2.2 to 2.5
3: 0
4: 0
5: 4.94
6: 0.55
7: 0
8: 4.55
9: 4.78
10: 0.33
11 through to 16:  2.4 (slight movement)

Frecuency central

NE5532

1:  0.13 to 4.9
2:  2.9 to 3.2
3:  2.7 to 3.1
4:  0v
5:  4.79
6.  4.9
7:  5.14
8:  9


PT2399

1:  5
2:  2.38 to 2.42
3:  0
4:  0
5:  2.75
6:  0.61
7:  0.88
8:  0.88
9 through to 16:  2.41 (slight movement)



I had a similar problem with my last build. Here's what it boiled down to for me -
1. make sure the 100R is 1k - it has to do with the PT2399 locking up
2. check the 330K behind the voltage regulator - mine drifted in value
3. check the 1meg from pin 7 on the opamp

In bypass. everything was fine, but no signal at all with the effect on. I found that when I touched the back of the PCB in the output path, I got hum .
I also a - touched up my solder connections
        b - checked every solder joint and trace for continuity and solder bridges
The end result was #3 above
#2 above took care of my voltage readings

Hope this helps. I was very pleased with the build once it was working.
Hi thanks for your input
Can you clarify what you mean by checking the 1M and the 330K? Do you simply mean checking their resistance is accurate?
I did indeed use a 1k rather than the 100R resistor mentioned.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: bluesman1218 on March 22, 2011, 08:01:45 AM

I had a similar problem with my last build. Here's what it boiled down to for me -
1. make sure the 100R is 1k - it has to do with the PT2399 locking up
2. check the 330K behind the voltage regulator - mine drifted in value
3. check the 1meg from pin 7 on the opamp

In bypass. everything was fine, but no signal at all with the effect on. I found that when I touched the back of the PCB in the output path, I got hum .
I also a - touched up my solder connections
        b - checked every solder joint and trace for continuity and solder bridges
The end result was #3 above
#2 above took care of my voltage readings

Hope this helps. I was very pleased with the build once it was working.
[/quote]
Hi thanks for your input
Can you clarify what you mean by checking the 1M and the 330K? Do you simply mean checking their resistance is accurate?
I did indeed use a 1k rather than the 100R resistor mentioned.
[/quote]

Yes, that's what I meant.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: ppaappoo on March 22, 2011, 06:41:42 PM
it's possible a softless lfo? like a sine wave or just modify the current lfo to make it more soft on the peaks?

thanks
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: ppaappoo on April 05, 2011, 05:35:05 PM
hello, how I can do to increase the volume of the signal delay? o maybe add a mix control.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: bluesman1218 on April 05, 2011, 06:13:18 PM
hello, how I can do to increase the volume of the signal delay? o maybe add a mix control.

Check Post #562 on this page. I'm thinking of using this version for my next build of this pedal.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: ppaappoo on April 05, 2011, 06:27:35 PM
hello, how I can do to increase the volume of the signal delay? o maybe add a mix control.

Check Post #562 on this page. I'm thinking of using this version for my next build of this pedal.

OK, thanks. I'm working in this chorus http://www.diystompboxes.com/smfforum/index.php?topic=90835.0
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: frequencycentral on April 05, 2011, 06:30:23 PM
hello, how I can do to increase the volume of the signal delay? o maybe add a mix control.

Little mod for anyone who's interested try changing the resistor connected to pin 15 to 22k, that makes the wet side a bit louder and sounds more chorusy to me. It might mess with to overall level though.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: GodSaveMetal on April 05, 2011, 10:07:51 PM

I had a similar problem with my last build. Here's what it boiled down to for me -
1. make sure the 100R is 1k - it has to do with the PT2399 locking up
2. check the 330K behind the voltage regulator - mine drifted in value
3. check the 1meg from pin 7 on the opamp

In bypass. everything was fine, but no signal at all with the effect on. I found that when I touched the back of the PCB in the output path, I got hum .
I also a - touched up my solder connections
        b - checked every solder joint and trace for continuity and solder bridges
The end result was #3 above
#2 above took care of my voltage readings

Hope this helps. I was very pleased with the build once it was working.
Hi thanks for your input
Can you clarify what you mean by checking the 1M and the 330K? Do you simply mean checking their resistance is accurate?
I did indeed use a 1k rather than the 100R resistor mentioned.
[/quote]

Yes, that's what I meant.
[/quote]

You tried to change the PT2399?? I change it with the original values and work fine with the new IC!!!!! some PT2399 can be failure!!!!!!!!!!!!!
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: ppaappoo on April 05, 2011, 10:49:06 PM
hello, how I can do to increase the volume of the signal delay? o maybe add a mix control.

Little mod for anyone who's interested try changing the resistor connected to pin 15 to 22k, that makes the wet side a bit louder and sounds more chorusy to me. It might mess with to overall level though.


(http://s1d2.turboimagehost.com/t1/6721324_LittleAngelMiracle-11.jpg) (http://www.turboimagehost.com/p/6721324/LittleAngelMiracle-11.jpg.html)
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Earthscum on April 05, 2011, 11:30:40 PM
If you swap the positions of the caps into the resistors' spots at the mixing section, and just put a 20k pot in where the caps were, outer to each cap, and wiper to where the caps used to tie together in the board, you have an adjustable mix. I would probably 'fly' in 4.7k's from either leg and use a 10k, though to limit the amount on either side. Or breadboard and find that sweet mix... 3.3k from the dry side and 5.6k from the wet into a 10k? Just ideas for ya.

on a side note, I keep ignoring this thread when it comes up because it makes me want to build an 'Uber-Angel', a bit of tweak-ability on everything. I already have two extra knobs on my angel, don't need more... but I got etch-happy and have a spare couple boards I really want to use, and maybe together... parallel, in the same box. It would be easy to do using what I described above to mix, then just a buffer and a mix to get them back to a single signal, a level pot, adjustable delays on both... ugh. Rick, I think an Angel might get a Rack... and I still want to make another Toe Jam, gotta finish my friend's Rat, rework a couple distortion designs... my girlfriend doesn't think I love her as much as the circuits.  :icon_confused:
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Earthscum on April 05, 2011, 11:49:29 PM
Oh yeah, Rick, I forgot to mention that I've been having no problems firing up ANY PT with 820R so far. 680R was kind of a crap shoot... out of the batches of newer ones, I wouldn't trust one that worked to keep it up forever. My first PT's still fire up fine with the 100R, as I'm sure all yours do too.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: bluesman1218 on April 06, 2011, 09:14:55 AM
You tried to change the PT2399?? I change it with the original values and work fine with the new IC!!!!! some PT2399 can be failure!!!!!!!!!!!!!

Before building, I ordered 3 PT2399s after reading the thread. Everything works fine once I fixed these problems.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: GodSaveMetal on April 06, 2011, 06:26:07 PM
You tried to change the PT2399?? I change it with the original values and work fine with the new IC!!!!! some PT2399 can be failure!!!!!!!!!!!!!

Before building, I ordered 3 PT2399s after reading the thread. Everything works fine once I fixed these problems.

I have a problem with one of my PT2399 how to fix em`??? yeah the other sound normal with no changes??? my PT2399 is wrong??? there is no effect with it the sound pass normal!!!!
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: frequencycentral on April 09, 2011, 08:53:22 AM
mictester over at the other place has developed a little sub-circuit to prevent the PT2399 from locking up:

 "The PT2399 datasheet warns about having a low value resistor from pin 6 to ground during the power-on reset that the IC does automatically. The reset lasts 400 ms. I keep pin 6 with a higher value resistor for longer than the reset period. I tried it, and the three ICs I tried it with did not lock up. With the 2N3904 I used, the delay was pretty much identical to that from a 100R resistor. "

It would appear to be verfied twice. Should solve people's problems with some PT2399 not liking this circuit.

(http://dl.dropbox.com/u/967492/Pin6Fix.jpeg)
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: ppaappoo on April 09, 2011, 10:54:01 AM
You tried to change the PT2399?? I change it with the original values and work fine with the new IC!!!!! some PT2399 can be failure!!!!!!!!!!!!!

Before building, I ordered 3 PT2399s after reading the thread. Everything works fine once I fixed these problems.

I have a problem with one of my PT2399 how to fix em`??? yeah the other sound normal with no changes??? my PT2399 is wrong??? there is no effect with it the sound pass normal!!!!

some PT2399 don't work with the 100R resistor to ground in the pin 6, try with 560R.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Govmnt_Lacky on April 09, 2011, 04:10:09 PM
Modest request  :icon_redface:

Could someone post a link to a good, recent demo for this pedal WITHOUT ANY OTHER EFFECTS IN THE CHAIN?

I still feel that my build sounds VERY, VERY Subtle compared to some of the demos I have heard however, most of those were used with delays, reverbs, etc.

I used 100K for both pots but others have done the same and their demos sound FAR better than my Angel.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: ralley on April 09, 2011, 06:35:15 PM
Modest request  :icon_redface:

Could someone post a link to a good, recent demo for this pedal WITHOUT ANY OTHER EFFECTS IN THE CHAIN?

This one (not my demo) seems to be Little Angel only: http://www.youtube.com/watch?v=tsbcD4txfZg&feature=related (http://www.youtube.com/watch?v=tsbcD4txfZg&feature=related)

Rob.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: cgibsong002 on April 10, 2011, 02:58:58 PM
I searched through the last 10 pages but didn't see anything... is there a vero layout for this?
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: ppaappoo on April 10, 2011, 03:55:15 PM
I searched through the last 10 pages but didn't see anything... is there a vero layout for this?

page 4!  ;)
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: cgibsong002 on April 10, 2011, 04:23:34 PM
I searched through the last 10 pages but didn't see anything... is there a vero layout for this?

page 4!  ;)

there was a pcb layout there but not a vero.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: frequencycentral on April 10, 2011, 05:32:38 PM
I searched through the last 10 pages but didn't see anything... is there a vero layout for this?

http://www.sabrodesign.com/wp-content/uploads/2010/10/Little-Angel.gif
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: cgibsong002 on April 11, 2011, 12:00:38 AM
I searched through the last 10 pages but didn't see anything... is there a vero layout for this?

http://www.sabrodesign.com/wp-content/uploads/2010/10/Little-Angel.gif

awesome thank you so much. is this the modified 'fixed' version?
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: hab on April 11, 2011, 02:21:18 AM
Here's the version with mictester's "lock-up" fix (yet to be verified): http://www.sabrodesign.com/wp-content/uploads/2011/04/LittleAngelRev1.gif (http://www.sabrodesign.com/wp-content/uploads/2011/04/LittleAngelRev1.gif)
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: robmdall on April 11, 2011, 09:23:15 AM
What is the group choice schematic to follow? Ricks original (version 2) or Earthscum's (post 141) ?

Bob
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Poste on April 13, 2011, 01:48:54 AM
Does the polarity protection diode need to be a 4007 can it be a 4001?

Thanks in advance
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Taylor on April 13, 2011, 02:13:09 AM
It can definitely be a 1n4001. Not sure why 4007 was chosen, probably was just the part that somebody had lying around. The only difference AFAIK is the amount of reverse voltage it can take, and the 4001 is good for 35 vRMS, which is more than it will ever see.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: frequencycentral on April 13, 2011, 11:33:42 AM
Not sure why 4007 was chosen, probably was just the part that somebody had lying around.

Yup!
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: funkyhead on April 23, 2011, 11:50:06 AM
Hi, I have made this circuit couple days ago but it doesn't work properly. There is some change in the signal but no effect. Only when i'm turning the depth pot sound is a bit modulated. I changed the resistor from pin6 of PT2399 to 1k an then to 4k7 and only I had one repeat and nothing else. I checked for short circuits and cold joints and didn;t find any. The chip as well as the op-amp are ok. Any idea what's the problem?
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: frequencycentral on April 23, 2011, 12:36:53 PM
If you're getting a single delay the PT2399 part of the circuit (ie the audio path) is working. Sounds like your LFO is not functioning to me.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: ppaappoo on April 23, 2011, 02:28:11 PM
check the speed pot connection.
disconnect the depth pot an place a led to see if the lfo works
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: funkyhead on April 24, 2011, 08:19:32 AM
I think you are right. Pots are fine. The led connected instead of depth pot didn't do a siongle thing. I kinda know what the LFO is but how to make it work? I think i'll use the osciloscope and if it'll showa that the LFO's not working I don't know what to do next.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: egasimus on April 27, 2011, 06:49:03 AM
Hey, I'm planning to build this soon with Earthscum's mods. Can the circuit, however, work with line levels? After I saw ADT mentioned in this thread, I'm tempted to use it as an insert on vocals :icon_smile:
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: frequencycentral on April 28, 2011, 03:04:06 PM
So I've been through my stash of PT2399 and found one that locks up intermittently. So I'm gonna forego the wedding tomorrow (  :o  ) and add the Pin 6 Fix kludge:

(http://dl.dropbox.com/u/967492/Pin%206%20Fix.gif)

The fix itself is verified but I wanna try it for myself. The layout above should sit in my 1590A Angel between the 9mm pots and the main PCB, I'm gonna bend C1 over to make the whole kludge flat. I guess also I should do a new layout incorporating the fix sometime. I think I could squeeze it so it's still a 1590A-able layout, or just 'spread out' so it's only 1590B-able. What do people think?
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Govmnt_Lacky on April 28, 2011, 03:16:54 PM
I thought the lock-up fix was solved with a 1K resistor off of Pin 6 of the 2399 chip instead of the 100R.  ???

Then again, I cannot see the picture in your post so.....  ::)
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: frequencycentral on April 28, 2011, 03:24:43 PM
Apparently the '1k at pin 6' fix works for some PT2399............and other PT2399 will work fine with 100R at pin 6. But mictester's pin 6 fix will make each and every little PT2399 in the whole wide world work in the Little Angel. With the added benefit that the resistance to ground from pin 6 is about 100R, which IMO is preferable to the extra latency that the '1k at pin 6' fix adds.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: GodSaveMetal on April 28, 2011, 03:55:56 PM
Apparently the '1k at pin 6' fix works for some PT2399............and other PT2399 will work fine with 100R at pin 6. But mictester's pin 6 fix will make each and every little PT2399 in the whole wide world work in the Little Angel. With the added benefit that the resistance to ground from pin 6 is about 100R, which IMO is preferable to the extra latency that the '1k at pin 6' fix adds.

Thanks for the UNIVERSAL FIX 2399!!! it is a great idea!! I have some Pt's that don't fix for the LITTLE ANGEL chorus!!! I will tried this for every Pt's!!! great!!!
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: egasimus on April 29, 2011, 07:43:42 AM
Rick - why don't you use vertically mounted resistors and diode? They would still be shorter than the electrolytic, anyway, unless it's one of those extra-tiny ones.
I've also been wondering about this - I want to build the Little Angel with Earthscum's 10k+10R mod at pin 6 - can this be combined with the anti-lockup mod?
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: frequencycentral on April 29, 2011, 07:50:46 AM
Rick - why don't you use vertically mounted resistors and diode? They would still be shorter than the electrolytic, anyway, unless it's one of those extra-tiny ones.

Risk of grounding against the enclosure in 1590A builds. The electrolylics are layed out so as to be bent over and layed flat.

I've also been wondering about this - I want to build the Little Angel with Earthscum's 10k+10R mod at pin 6 - can this be combined with the anti-lockup mod?

Sure, just add the pot in series between the 47R and pin 6.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: funkyhead on April 29, 2011, 09:54:00 AM
Halleluyah! Heil to the PT2399 unlocker! Heil to Frequencycentral! You're the greatest  :icon_biggrin:
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: cgibsong002 on May 10, 2011, 01:17:05 AM
Hey guys... desperate need of some quick help here. I'm actually building this as a project for my circuits class. We weren't allowed to do pcb so I used the bolstad vero layout. Bypass is good, and when switched on it sounds basically exactly the same as bypass, with a touch more noise. It seems as if my switch or something were shorted from input to output but i dunno. What is this 'lock-up'? I tried reading through all the pages about the pt2399 locking up but i haven't a clue what that means. would that cause a problem like i'm having? i originally used the 47 ohm that it called for, and then switched to a 470 ohm since i don't have a 1k. I figured I'd ask here before keep switching out resistors.

here are my values


5532 (Volts)
1.   5.19
2.   4.92
3.   4.79
4.   0
5.   3.65
6.   3.09
7.   8.80
8.   9.46
PT2399
1.   5.02
2.   2.40
3.   0
4.   0
5.   1.30
6.   2.36
7.   .55
8.   .69
9.-16. 2.42

2N3904
C. 1.69
B. 0.00
E. 0.00

Regulator
9.46 =IN  5.02=Out
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Govmnt_Lacky on May 10, 2011, 11:08:02 AM
Hey guys... desperate need of some quick help here. I'm actually building this as a project for my circuits class. We weren't allowed to do pcb so I used the bolstad vero layout. Bypass is good, and when switched on it sounds basically exactly the same as bypass, with a touch more noise. It seems as if my switch or something were shorted from input to output but i dunno. What is this 'lock-up'? I tried reading through all the pages about the pt2399 locking up but i haven't a clue what that means. would that cause a problem like i'm having? i originally used the 47 ohm that it called for, and then switched to a 470 ohm since i don't have a 1k. I figured I'd ask here before keep switching out resistors.here are my values


5532 (Volts)
1.   5.19
2.   4.92
3.   4.79
4.   0
5.   3.65
6.   3.09
7.   8.80
8.   9.46
PT2399
1.   5.02
2.   2.40
3.   0
4.   0
5.   1.30
6.   2.36
7.   .55
8.   .69
9.-16. 2.42

2N3904
C. 1.69
B. 0.00
E. 0.00

Regulator
9.46 =IN  5.02=Out


Try the 1K resistor. If that does not work, then you may want to try a different 2399 chip.

Good Luck  ;D
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: cgibsong002 on May 10, 2011, 02:13:04 PM
didn't have a 1K so soldered two 480's in series... figured that was close enough (unless there's some magic number about the 1K mark). still nothing. tried two other different pt2399's... still nothing. tried a different power source, nothing..

wth??
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Govmnt_Lacky on May 10, 2011, 02:43:49 PM
didn't have a 1K so soldered two 480's in series... figured that was close enough (unless there's some magic number about the 1K mark). still nothing. tried two other different pt2399's... still nothing. tried a different power source, nothing..

wth??

Can you post a link to the layout you are using?

I don't remember a 3904 being in Rick's circuit  ???

Also, I think that at least helf of your LFO should be wobbling and it is not by looking at your readings.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: frequencycentral on May 10, 2011, 02:59:42 PM
I don't remember a 3904 being in Rick's circuit  ???

We weren't allowed to do pcb so I used the bolstad vero layout.

He's using Sabro's vero. Sabro updated it with the 3904 based Pin 6 Fix.  

http://www.sabrodesign.com/wp-content/uploads/2011/04/LittleAngelRev1.gif

Also, I think that at least helf of your LFO should be wobbling and it is not by looking at your readings.

+1, there should not be static voltages on pins 5, 6 and 7 of the NE5532. That's your problem.

I posted these voltages earlier in the thread. Note the voltages of the LFO part of the NE5532. By the way, the vero uses the 'other side' of the NE5532 for the LFO to the PCB version I built.

 NE5532

1:  0.13  to   4.9
2:  2.9    to   3.2
3:  2.7    to   3.1
4:  0v
5:  4.79
6.  4.9
7:  5.14
8:  9

PT2399

1:  5
2:  2.38   to   2.42
3:  0
4:  0
5:  2.75
6:  0.61
7:  0.88
8:  0.88
9 through to 16:  2.41 (slight movement)
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: cgibsong002 on May 10, 2011, 06:45:19 PM
Yeah. I just unsoldered both IC's and the tranny so I could put in sockets. I tested multiples for all three components, with nothing changing. I also put in the 1K resistor, as well as tried it with my power supply, a battery with 8V on it and a battery with 9.25 on it. Nothing.

So yeah, I'm getting static voltages on pins 1-3. Now that I know this is an issue, where do I look to fix it? I can't find any issues on my board unless there's some damn micro traces. Which reminds me... I'm never using vero again. Looks good on paper. Sucks dick building it  :icon_evil:
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: frequencycentral on May 10, 2011, 06:57:29 PM
If you are using Sabro's vero, it's pins 5, 6 and 7 you need to get moving, not 1, 2 and 3. Check for shorts. Triple check all track cuts for micro bridges. Quadruple check all values. Make sure the IC is actually the right way around. Check off board wiring to speed pot. Etc
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: frequencycentral on May 10, 2011, 06:59:16 PM
I'm never using vero again. Looks good on paper. Sucks dick building it  :icon_evil:

Yeah, I hate the stuff. I don't understand people's attraction to it.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: bluesman1218 on May 10, 2011, 07:45:40 PM
I'm never using vero again. Looks good on paper. Sucks dick building it  :icon_evil:

Did my 1st build on vero and couldn't get it to work. Must've been micro solder bridge? Some folks love it, not me... yet.

Govmnt_Lacky "I don't remember a 3904 being in Rick's circuit"
That was from the fix added on this page
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: cgibsong002 on May 10, 2011, 07:54:44 PM
If you are using Sabro's vero, it's pins 5, 6 and 7 you need to get moving, not 1, 2 and 3. Check for shorts. Triple check all track cuts for micro bridges. Quadruple check all values. Make sure the IC is actually the right way around. Check off board wiring to speed pot. Etc


wait.. i'm not quite sure I understand. My values kind of match up with yours as far as pin 1-pin 1, pin 2- pin 2, etc. go. am i supposed to get similar values to you, except 5,6,7 will oscillate? Or should all my pin values be opposite of yours.. i.e. on the other side of the op-amp. and my 5532 is definitely in the right orientation. started popping as soon as i plugged it in with it flipped.

ok my pots. looking at them from the bottom, it goes 3, 2, 1 left to right, correct? then I shorted 1 and 2 together on each pot
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: frequencycentral on May 10, 2011, 08:01:55 PM
My PCB layout uses pins 1,2 and 3 for the LFO, Sabro's vero uses pins 5, 6 and 7 for the LFO. Look carefully at the orientation on each layout. If you've had your NE5532 in the wrong way around at any point it will be dead now.

Your pots should be fine.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: cgibsong002 on May 10, 2011, 08:24:56 PM
My PCB layout uses pins 1,2 and 3 for the LFO, Sabro's vero uses pins 5, 6 and 7 for the LFO. Look carefully at the orientation on each layout. If you've had your NE5532 in the wrong way around at any point it will be dead now.

Your pots should be fine.

it appears to still be fine, but i've got plenty so no worries.

i'm baffled right now about the jump across R10. My meter is telling me I have continuity across there... but the gap across my cut is huge. I haven't used the continuity function much, but is there something i'm missing here? is this my problem or is there something i'm not seeing in the circuit where there should be continuity there?
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: cgibsong002 on May 10, 2011, 08:53:37 PM
Uhh... I just noticed. On the vero layout there's an R22 parallel to the 1n4148. However it is not listed in the parts list. May have just found the culprit?

EDIT: Ok.. so after reading through every single page, I think I found my answer on like the last page. Is R22 supposed to be the 68K resistor?

EDIT EDIT EDIT:  >:( >:( ??? Still no good. It has to do with this continuity I have across the 1M resistor... because if that was shorted then it would pretty much just go from input through a 100K resistor back to output (I think?). But I don't see how, I've completely mutilated that cut and it's still reading 0 on my continuity meter.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: cgibsong002 on May 11, 2011, 03:29:15 PM
nope.. i'm an idiot. i finally looked over the schematic and realized the 1M ohm resistor was grounded from input. so when my effect is switched off the input is also grounded which is why i was getting continuity across that gap.

so now i'm still stuck. could this possibly have to do with lock-up, or not likely since i never get any chorus effect?
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Govmnt_Lacky on May 11, 2011, 03:32:50 PM
so now i'm still stuck. could this possibly have to do with lock-up, or not likely since i never get any chorus effect?

Just keep in mind that this is NOT a CE-2 or a Small Clone  ;)

The chorus effect is VERY subtle.

Good Luck  ;D
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: frequencycentral on May 11, 2011, 03:46:03 PM
The chorus effect is VERY subtle.

Is it? I never thought so. Have a listen to my soundclips.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Govmnt_Lacky on May 11, 2011, 03:57:33 PM
The chorus effect is VERY subtle.

Is it? I never thought so. Have a listen to my soundclips.

I listened to A LOT of sound clips however, I could never get my Angel to sound like some of them. I have consulted quite a few people about this and most of them agreed. I even went as far to ship my build to another continent and have someone else give it a go (Thanks again Chris  ;D) He told me that it sounded just like his.

To me it just sounds subtle. Compared to a CE-2 or a Small Stone that is.

Can you link a particular sound clip that is a good example?

Don't get me wrong... it still has its place in my pedal chain!  ;)
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: frequencycentral on May 11, 2011, 04:19:06 PM
Can you link a particular sound clip that is a good example?

http://www.diystompboxes.com/smfforum/index.php?topic=86297.msg722615#msg722615
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: cgibsong002 on May 11, 2011, 04:28:05 PM
oh believe me... I'd know if it was working right, lol. There wouldn't be 30 pages if it sounded like a clean input.

and ok... i've literally double and triple checked the whole pedal. i ran along every single trace with a blade to make sure there were no bridges. i double checked every value and positioning of every component. I have no clue what else I can do. Has anyone verified this layout?? If so, how would I know if I maybe have a bad cap or something? Can't see what else it would be aside from those two options.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Renegadrian on May 11, 2011, 07:04:01 PM
I'm never using vero again. Looks good on paper. Sucks dick building it  :icon_evil:

Yeah, I hate the stuff. I don't understand people's attraction to it.

 :icon_eek:
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: cgibsong002 on May 11, 2011, 07:28:37 PM
Hallelujah! It turns out my 100K pot was bad. Replaced it and we're all good now! My report was technically due yesterday, but whatever. Sounds good! I'm going to try dropping the 1K down to the 47R now.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: deadastronaut on June 05, 2011, 08:06:38 PM
hi rick!..

which layout is the best for this, page 4?..........i love it..i was looking for an alex lifeson type chorus and this sounds like its it!...(think red barchetta)

is this cool with an overdriven type sound too?..

i have a spare 2399 laying around and right fancy this!!!!!....nice!.

Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: frequencycentral on June 06, 2011, 08:45:31 PM
hi rick!..

which layout is the best for this, page 4?..........i love it..i was looking for an alex lifeson type chorus and this sounds like its it!...(think red barchetta)

is this cool with an overdriven type sound too?..

i have a spare 2399 laying around and right fancy this!!!!!....nice!.



Yup, page 4. Or the 1590A layout on page 9.

Although I'll be doing a new layout for LA's 1st birthday, incorporating some improvements like the pin 6 fix and seperate vref.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: iccaros on June 06, 2011, 11:44:17 PM
Cool I have 4 PT2399 on order, now I need a crap load of  low profile and love voltage caps, for some reason my 450volt caps don't fit well in a pedal...

Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: deadastronaut on June 07, 2011, 07:03:31 AM
cool....so when is little angels birthday?...is it on the 28th..like mine!.it'll make a good prezzie... :icon_wink:

(did you get that printer btw?)..mines great!..

Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: egasimus on June 07, 2011, 08:26:54 AM
I'm so looking forward to that. The Little Angel is on my project list. Also on my layout making list though, since you'll probably want to keep it simple, and I want the mods ITT :)
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Perrow on June 07, 2011, 10:13:55 AM
... and love voltage caps ...

Where do you buy those  :icon_eek:
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: egasimus on June 22, 2011, 09:21:49 AM
(originally posted this in the Echo Base topic... silly me)
So I made a new layout for the Little Angel. It includes the dry/wet mod and the potentiometer on pin 6 mod. It should theoretically fit into a 1590a, too, although I haven't tried it - I can't source a 1590a box, and I don't have much time or money on my hands for the time being, either. But I think I'll find a couple of minutes to prepare and post the layout, if you're interested. This week, that is.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: deadastronaut on June 22, 2011, 09:28:32 AM
of course!..nice one!.... :icon_cool:
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: frequencycentral on June 22, 2011, 01:30:17 PM
^^^

Well I was gonna save this as a surprise for LA's 1st birthday in August, but........

(http://dl.dropbox.com/u/967492/LA%20Birthday%20Edition/LA%20Birthday%20PCB.gif)
(http://dl.dropbox.com/u/967492/LA%20Birthday%20Edition/LA%20Birthday%20PnP.gif)

I wanted to keep it 1590A-able, but also add good things like the Pin 6 Fix and a seperate vref for the audio path. Here's the lowdown:

 
As it's planned to be 1590A-able, hopefully all the electro caps should be able to be bend over 900 to lie flat against the PCB. C16 might be the trickiest.

I PM'ed this layout last week to a couple of people who expressed interest in verifying it, so you never know, it could be verified within a day or so. The layout does need a little tidy up, as I notice the pad sizes are not all the same size.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: deadastronaut on June 22, 2011, 01:34:34 PM
whhhooohooo...happy early birthday LA.... :icon_cool: :icon_mrgreen:

nice one rick..
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: jvanoort on June 23, 2011, 05:36:33 AM
Here is a little demo of my pedal. I added a 0.1uf cap across the 47uf one (in parallel) to get rid of some excess hiss.

Never mind the playing, just demoing the pedal  :)

Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: deadastronaut on June 23, 2011, 05:47:21 AM
@jvanoorrt:

nice. its great to see and hear this....thanks!.. :icon_cool:

i didnt hear any hiss on ricks original recording though?....hmmm..
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: jvanoort on June 23, 2011, 06:18:35 AM
Well, I did have some hiss. I also placed the additional cap across the 47uf one and after the recording also replaced the 1nf cap that connects leg 15 and 16 of the pt2399 with a 3.3nf cap. Makes the sound a tad darker, more in line with the dry signal, and removes the leftover hiss.

Very satisfied with this pedal.  :)
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: deadastronaut on June 23, 2011, 06:48:42 AM

Very satisfied with this pedal.  :)

you should be, sounds great!...i was waiting for the rat to go on with it!...mild overdrive type..sort of alex lifeson style. ;)
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: jvanoort on June 23, 2011, 06:57:02 AM
Ah, I might do that in another demo, but I prefer chorus in an otherwise clean signal :-)
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: WiLL_GS on June 25, 2011, 10:56:39 AM
Hello guys! I'm from Brazil, and it's my first time here. I found this topic and I liked a lot. Than, I decided to make a Little Angel. I've got the components and I build it, but didin't worked. I plugged my guitar, and befote I turn on the Little Angel, the sound's guitar is normal, but when I turn on, I don't hear any noise more. I've verificad, there is no point of short circuit. This is the model that I follow:  http://imageshack.us/photo/my-images/39/111xl.gif/. I think I made a mistake somewhere, but someone but someone has already built this circuit and it worked correctly?? One more doubt, I just find this layout: http://imageshack.us/photo/my-images/4/layout1111.jpg/ . I tried to print several times, but the size was not the same as the circuit, so I did another by following links from this, only then could the actual size for the components. At least that part I know is right because I checked several times. I'd like to know how you get to print the same size as real. If I do not think the problem the way I did, I do it again with the original layout. Later I'll post some pictures of this project, other guitar pedal and also my amp, I did it by myself, all are very simple but work fine. Please help me! See you later, thanks a lot!!!
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Govmnt_Lacky on June 25, 2011, 01:15:32 PM
Hello guys! I'm from Brazil, and it's my first time here. I found this topic and I liked a lot. Than, I decided to make a Little Angel. I've got the components and I build it, but didin't worked. I plugged my guitar, and befote I turn on the Little Angel, the sound's guitar is normal, but when I turn on, I don't hear any noise more. I've verificad, there is no point of short circuit. This is the model that I follow:  http://imageshack.us/photo/my-images/39/111xl.gif/. I think I made a mistake somewhere, but someone but someone has already built this circuit and it worked correctly?? One more doubt, I just find this layout: http://imageshack.us/photo/my-images/4/layout1111.jpg/ . I tried to print several times, but the size was not the same as the circuit, so I did another by following links from this, only then could the actual size for the components. At least that part I know is right because I checked several times. I'd like to know how you get to print the same size as real. If I do not think the problem the way I did, I do it again with the original layout. Later I'll post some pictures of this project, other guitar pedal and also my amp, I did it by myself, all are very simple but work fine. Please help me! See you later, thanks a lot!!!

Try here and then repost:

http://www.diystompboxes.com/smfforum/index.php?topic=29816.0

Good Luck  ;D
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: WiLL_GS on June 25, 2011, 08:53:36 PM
I'm back! I found the problem, there were some poins of short circuit. I turned on and worked. But, I think that the sound wasn't good as a delay. Is someone has the same pedal build?? I 'd like to hear the sound, and compare whith the my. I 'll poste the sound of my, then you listen and tell me to know what you think of this. Here the video of my amp: http://www.youtube.com/watch?v=Y_j7QtAaLX4
I connect my guitar on this amp, using other pedal as a preamplifier(that has a fuzzy efect too), and I get a good result. Thanks!!  

    
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: WiLL_GS on June 26, 2011, 10:14:41 PM
I'm back again!! Today I recorded the sound of the Little Angel. I don't know if the sound is normal, I think that there is something wrong. This is the link of the sound of the Little Angel(only this) : http://www.4shared.com/audio/F5Pk6aIe/4_online.html . There is more one: http://www.4shared.com/audio/K4kVwhRR/sound2.html. Now I mixed the sound of my fuzzy and the ange: http://www.4shared.com/audio/lEgE96wL/fearfuzzydelay.html. PS: I don't play guitar very well, nay, I'm very bad Oo. Now some pictures of them(I put them in a pack .rar to facilitate) : http://www.4shared.com/file/E303rpDQ/Pictures.html . All files don't have any virus!! Please tell me what you think about the sound, and the pictures to =]. Bye.   
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Pigyboy on June 27, 2011, 06:14:43 AM
(http://i852.photobucket.com/albums/ab86/pigyboy_2009/100_1549.jpg)
Verified!

Not too hissy and works with all the PT2399's I have here even with R22<100 ohms.

I used a 2N5087 instead of a 2N3906 and two tiny 4.7uf in parallel for C16. Also went with the film 180nf caps as all the .1's I have are too big or ceramics.  I socketed R22 and using a 51 ohm resistors slows down the delay time a bit more. I think I will try a 100KC (as per Slade) for the speed pot to see what if I can spread the range adjustment out.

Thanks Rick!

Cheers,
Chris
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: frequencycentral on June 27, 2011, 01:41:07 PM
^^^

Nice to see it verified so quick, thanks Chris.  ;)
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: bigmufffuzzwizz on June 29, 2011, 11:38:27 AM
Just finished my LA the other day and I'm pretty satified with it. I'm able to get lots of different cools sounds from it. I wanna give your birthday edition a go since I like this last one so much. And great job on making it super simple! Are there any other mods I can try besides the adjustable delay time and wet/dry pot?  :)
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: deadastronaut on June 29, 2011, 11:43:02 AM
could this still be a delay too!?..
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Scruffie on June 29, 2011, 12:00:23 PM
So is there an updated schematic with these fixes...?

If so I might do an Onboard Pot 1590B with room for battery PCB...
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Seven64 on June 29, 2011, 02:29:15 PM
i dunno about the birthday version, but i did a vero of the original and just finished troubleshooting it last night and am loving it!!!! great sounding pedal!!!!!
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: frequencycentral on June 29, 2011, 04:08:04 PM
So is there an updated schematic with these fixes...?

If so I might do an Onboard Pot 1590B with room for battery PCB...

Schematic for the Birthday Edition:

(http://dl.dropbox.com/u/967492/Little%20Angel%20Miracle%203.PNG)
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: merlinb on June 29, 2011, 04:50:53 PM
R2 and R6 don't seem to be doing anything... did you mean to add the extra shunt capacitors to make second order filters?
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Brymus on June 30, 2011, 07:41:25 PM
^^^

Well I was gonna save this as a surprise for LA's 1st birthday in August, but........

(http://dl.dropbox.com/u/967492/LA%20Birthday%20Edition/LA%20Birthday%20PCB.gif)
(http://dl.dropbox.com/u/967492/LA%20Birthday%20Edition/LA%20Birthday%20PnP.gif)

I wanted to keep it 1590A-able, but also add good things like the Pin 6 Fix and a seperate vref for the audio path. Here's the lowdown:

  • Pin 6 Fix: D1/C16/Q2/R21/R22
    I did add a little Pin 6 Fix subcircuit to a PT2399 that I know won't work without. It still has issues, but I think raising R22 to 100R and C16 to 47uF will sort it
  • Audio vref: R23/R24/C17 - suggested by merlinb as a way to reduce noise dumped into the older version's 5v vref supply by the PT2399
  • C4 changed to 3.3nF - might be a bit darker but will be less hissy
 
As it's planned to be 1590A-able, hopefully all the electro caps should be able to be bend over 900 to lie flat against the PCB. C16 might be the trickiest.

I PM'ed this layout last week to a couple of people who expressed interest in verifying it, so you never know, it could be verified within a day or so. The layout does need a little tidy up, as I notice the pad sizes are not all the same size.
I am a little confused Rick .
Is R1 just bypassing D1 ? and why ? and why isnt it on the schematic ?
Shouldnt R1 be in series with D1 ?

That last sound clip that was posted by Jvanort sounded really good,thanks for the demo.
I hope to finally get mine built next week.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Brymus on July 01, 2011, 12:07:59 AM
OK I see it on the schematic now,doh.
So the diode is just polarity protection for the gate of the npn,and the 68k limits the current,is that about right ?
I remember now some people were having trouble with the 100r ,so thats a work around to keep the shortest delay time possible I'm guessing.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: merlinb on July 01, 2011, 03:59:14 AM
So the diode is just polarity protection for the gate of the npn,and the 68k limits the current,is that about right ?
The 68k+47u causes the transistor to switch on slowly at power up, which prevents the PT2399 from going into latch up.
The diode allows the cap to discharge quickly at power down, so the circuit is immediately ready for the next power up (otherwise the PT might latch up is someone switched the power on/off too quickly)
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Brymus on July 01, 2011, 05:07:23 AM
Thanks for the explanation Merlin !

I breadboarded this,well 3 times actually double checking all my connections.
And I could not get any chorus,any warble to be accurate.
Turning the rate pot would yield a wah like effect while turning it,but turning the speed knob gave no change.
I tried different IC's,my PT2399's are a year or two old at least,I can get delay from it by increasing the 100R just no chorus.
Its like my LFO isnt oscillating I tried TL072, RC4558 and (NE5532 the only one to yield the wah sound) the rest had no modulation.
I get 2.5V at pin 2 but its stable doesnt wiggle at all.

Any suggestions ? 4 hours of this and I put everything back in the bins ,I will try again this weekend. :icon_redface:
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Brymus on July 01, 2011, 07:19:52 AM
I tried again same result,used all metal film resistors this time and a different layout on the breadboard.
I noticed the schematic says 2n3904 the PCB /layout says 2N3906
I tried with just the 100r to ground and actually had some modulation it was slight but the speed knob did affect the speed and the depth made the effect more or less noticable.
Absolutely no where near as modulated as the sound clips that are posted though.
With 2n3904 the 4148 got really hot,so tried 2n3906 the 4148 wasnt hot but still no modulation just a very slight reverb and a couple db of boost.
I seriously have tripple checked the values and connections ,just cant get it working.
Title: Layout error
Post by: merlinb on July 01, 2011, 07:48:15 AM
I seriously have tripple checked the values and connections ,just cant get it working.
It should be 2N3904 (or any NPN). Sounds like your diode is backwards.

You could also add a 10k resistor + LED from the output of the LFO (pin2) to ground, that way you get a visual check that the LFO is working (cuz is flashes...).
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Pigyboy on July 01, 2011, 10:12:25 AM
I finally just got back to this after getting it to work the other day with Rick's new layout.  I built it with a pnp as per the pcb layout and it did fire up so I changed the transistor and it is still working the same but like Brymus mentioned it is not like the others I have here. There is no depth or lushness though all the knobs work. My PT is getting a little hot but not too bad. Gonna look at the two pedals side by side and see if I can get anywhere.
Title: Re: Layout error
Post by: Brymus on July 01, 2011, 04:30:57 PM
It should be 2N3904 (or any NPN). Sounds like your diode is backwards.

You could also add a 10k resistor + LED from the output of the LFO (pin2) to ground, that way you get a visual check that the LFO is working (cuz is flashes...).
thanks again Merlin ,thats a great idea.
I will try it later when I can.
I left it on the breadboard this 4th time,  ::) 
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Brymus on July 01, 2011, 05:09:32 PM
OK the 10k isnt needed since its at 2.5 v ,still no flash just constant dim light.
Ive tried 4 different op amps ,two types of NE 5532,no LFO  :icon_frown:
Its wired right to.
Any ideas ? anyone,maybe a diferent LFO set up IDK ?
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Earthscum on July 01, 2011, 07:52:26 PM
Any ideas ? anyone,maybe a diferent LFO set up IDK ?

Try different pots... you may have fried a lug? I have a non-functioning LFO section I gotta troubleshoot tonight, and probably upgrade with the new parts.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Brymus on July 01, 2011, 08:03:25 PM
I built a new seperate LFO with a TL072.
Got it modulating between 2V and 3V,but when I connect it to pin 2 it just stabilizes to 2.5V
There is a slight modulated effect but still not anything like it should be.
Is there an internal cap on the 2399 that stabilizes the Vref ?
Everything is exact to the schematic .
Any ideas ?
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Earthscum on July 01, 2011, 08:43:10 PM
I wonder... try firing it up with a 2k or larger pot (set above 2 k) with a 100R in series to ground. Then after a second or 2, turn the pot down. See if that works. I wonder if the transistor isn't trying to compensate for the warble for some reason? That's the last place I can think of.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Brymus on July 01, 2011, 10:47:24 PM
I wonder... try firing it up with a 2k or larger pot (set above 2 k) with a 100R in series to ground. Then after a second or 2, turn the pot down. See if that works. I wonder if the transistor isn't trying to compensate for the warble for some reason? That's the last place I can think of.
I used a 100k pot,that gave me a nice adjustable delay/reverb but still pin 2 stays right at 2.5 v,it only moves a couple hundreths of a volt when turning the speed or depth knobs.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Brymus on July 02, 2011, 01:26:28 AM
If I connect my LFO to pin 6 I get a weird pitch shift tune/detune effect on the repeats though
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: merlinb on July 02, 2011, 04:34:20 AM
OK the 10k isnt needed since its at 2.5 v ,still no flash just constant dim light.
You do need the resistor! If you just hook an LED up to the output of the LFO it will stop it oscillating!
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Earthscum on July 02, 2011, 03:01:50 PM
Straight from Merlin's Pdf:
"A significant source of noise is due to the internal clock modulating the power supply rail.
The following advice may be used to minimise this noise:

-----
• Leave the digital ground (pin 4) unconnected; it is already connected to the analog
ground internally via a ~10Ω resistance."

2 thoughts here:

First, for the people still getting noise, maybe try cutting the trace between pin 3 and 4. If it does bad things (I doubt it), then you can always solder bridge it back together. I think that ground may be for connecting to the other digital grounded circuits, such as whatever you are using the clock out from Pin 5 to drive, so that it acts as line noise canceling circuit. Another thought on that is maybe playing with a cap from Pin 4 to ground or another pin, maybe even + supply? Anyways...

Secondly, "A significant source of noise is due to the internal clock modulating the power supply rail." I wonder if the weak signal isn't coming from the supply compensating through such a large cap to ground. Maybe use a smaller cap to ground and see if the LFO signal improves? Maybe a 10uF Tant if you have one.

ETA: Just had a head-slapper. If anyone has this breadboarded, maybe try connecting the delay resistance to pin 4, leaving pin 4 unconnected from ground. Looking at the suggested circuits on the datasheet, those are the only 2 pins that are labeled as eventually terminating at a digital ground. Since there's no other circuitry that requires the digital ground's rail, we can leave it unconnected from anything else in the circuit. Thus, the digital ground and the delay resistance will be coupled together, and isolated from Analog ground by 10 ohms. It makes sense to me in a wierd way.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Brymus on July 03, 2011, 01:21:11 AM
OK can someone check their chips with a capacitance meter?

With no power I get 3.74 uf between pin 2 and ground,definitely enough to kill the chorus effect.
As noted on the first page, 1uf will stop the modulation.
WEIRD PART:
With power on it measures 374 uf exactly 100 times more,and it varies a bit too.(the Vref might be messing with my meter IDK)

All (4) of my PT2399 are 2-3 years old from Tayda,stamped with the PTC logo.

EDIT: This was measured with nothing but the meter + IC connected at pin 2,and the rest of the circuit still set up.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: merlinb on July 03, 2011, 04:06:24 AM
With no power I get 3.74 uf between pin 2 and ground,definitely enough to kill the chorus effect.

EDIT: This was measured with nothing but the meter + IC connected at pin 2,and the rest of the circuit still set up.
In circuit your meter is registering the impedance to ground from pin-2, which includes the LFO capacitors, so it's a false reading. There is no internal capacitor on pin 2.

Quote
I built a new seperate LFO with a TL072.
Got it modulating between 2V and 3V,but when I connect it to pin 2 it just stabilizes to 2.5V
How / where are you measuring those voltages?
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Earthscum on July 03, 2011, 11:31:59 AM
Brymus... try the pin 4-6 fix. I know 95% for sure that it shuts up the chip up, and my SPRV is more stable. I think we've all missed a big part of the PT2399 design, isolation of digi and analog grounds. My thinking is that your chip may be sensing the warble through the delay pin and compensating for it somehow. I fixed my LFO problem, lol... new battery, but it seems like my LFO is a bit more "active" in the circuit, if that makes any sense. It's gonna take some more checking, but I think the digital ground thing may be what stabilizes quite a few of these anomalous glitchy builds that obviously should have worked just fine.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Govmnt_Lacky on July 03, 2011, 03:44:57 PM
Thanks for the explanation Merlin !

I breadboarded this,well 3 times actually double checking all my connections.
And I could not get any chorus,any warble to be accurate.
Turning the rate pot would yield a wah like effect while turning it,but turning the speed knob gave no change.
I tried different IC's,my PT2399's are a year or two old at least,I can get delay from it by increasing the 100R just no chorus.
Its like my LFO isnt oscillating I tried TL072, RC4558 and (NE5532 the only one to yield the wah sound) the rest had no modulation.
I get 2.5V at pin 2 but its stable doesnt wiggle at all.

Any suggestions ? 4 hours of this and I put everything back in the bins ,I will try again this weekend. :icon_redface:

Any news on this Brymus?

I want to build the new layout so I am keeping an eye on this  ;)
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Brymus on July 05, 2011, 01:55:24 AM
With no power I get 3.74 uf between pin 2 and ground,definitely enough to kill the chorus effect.

EDIT: This was measured with nothing but the meter + IC connected at pin 2,and the rest of the circuit still set up.
In circuit your meter is registering the impedance to ground from pin-2, which includes the LFO capacitors, so it's a false reading. There is no internal capacitor on pin 2.

Quote
I built a new seperate LFO with a TL072.
Got it modulating between 2V and 3V,but when I connect it to pin 2 it just stabilizes to 2.5V
How / where are you measuring those voltages?
There was nothing connected at pin 2 ,I unhooked the LFO from the circuit when I measured the capacitance at pin 2.
So any capacitance couldn't have come from the LFO on another board that was disconnected at the time.

I was disconnecting the lead from pin 2 to my LFO and measuring the voltage there on the flying lead from the LFO board,not pin two.
With my DMM connected to that and ground it would fluctuate between about 1.8 and 3.1/3.2 VDC the speed knob would make it bounce between voltages faster or slower.
I can change the voltage divider and other resistor/s to get a greater voltage swing but am unsure what is safe to apply at pin 2 ?
Since the Vref is supposed to be 2.5V,I thought 2-3V was right.

I had a show Saturday afternoon ,and DIYSB was down all day today for me.      ( ? any one else ? )
So I havent tried anything else,I am thinking anout getting new chips and trying again.

I mean I can get delay,lots of delay ,and reverb from the chip by changing the 100R resistor to ground.
So the chip isnt latched up,if its delaying right ?

I appreciate the help and reply's if anyone has any ideas ,it is still on my breadboard.(both the LA and the seperate LFO)
I will post the voltages in my next post if that will help.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: makaze808 on July 15, 2011, 05:57:39 AM
Hi, is the  new layout OK to build yet ?  Thanks.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: deadastronaut on July 17, 2011, 03:39:41 PM
Archangel????? :icon_mrgreen:.....
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Pigyboy on July 26, 2011, 06:14:35 AM
On a second look my build of the birthday angel works but not really right and my experience with the angels is if it don't work and there are no visible mistakes is build a new one. Even if the birthday version works I didn't do a good enough job on the build to cram it in a little box either,
So I built a new one from the original 1590A and built one of mctesters fix boards and when I hooked it up using the 5 volts supply line it didn't work and made the 2399 & the 7805 hot real fast. I measured 40 mV at the output to pin 6. When I hook it up to the 9v line I am getting 29mV and everything works without getting too hot. I don't know what the math is here but maybe someone can help out here with what is going on.
Here is a little trick with the 100uf cap
(http://i852.photobucket.com/albums/ab86/pigyboy_2009/100_1699.jpg)
I shoehorned it between the two IC's and took the connections from corresponding points on the top of the board.
You can also see I socketed R1 to see if the circuit would work with out the fix....

Cheers.
Chris
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: deadastronaut on July 26, 2011, 10:02:17 AM
@chris

did your original page 4 version work ok?..still waiting to build this... :)
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Pigyboy on July 26, 2011, 11:19:48 AM
@chris

did your original page 4 version work ok?..still waiting to build this... :)
The one from page 9 for the 1590A's definitely works with the pin 6 fix (like the one pictured above)  I am not sure if anyone got the BDay version to work totally right yet. Turns out the sound out of mine is really weak compared to the one above.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: askwho69 on July 26, 2011, 11:52:33 AM
@chris

did your original page 4 version work ok?..still waiting to build this... :)
me too hahahha wanting to make this REALLY!!! @@ but im so confused which the best layout and verified with no mistakes... man its hard to scan on this threadtoo many pages!! like reading a whole book!
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: deadastronaut on July 26, 2011, 01:39:32 PM
thinking about  bread boarding this, so i can tinker with it,  will an 072 be ok, instead of 5532 ?...



Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Scruffie on July 26, 2011, 01:48:12 PM
@chris

did your original page 4 version work ok?..still waiting to build this... :)
me too hahahha wanting to make this REALLY!!! @@ but im so confused which the best layout and verified with no mistakes... man its hard to scan on this threadtoo many pages!! like reading a whole book!
There might be a new layout today if this last bit of the puzzle goes well  :icon_wink:
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: deadastronaut on July 26, 2011, 01:58:02 PM
cool,  :icon_cool:

edit: would an 072 be ok?..
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Scruffie on July 26, 2011, 04:10:49 PM
Another Layout for the Birthday Edition! Not my neatest and 3 jumpers but it seems okay and there should be plenty of space for components.

Onboard Pots (Mounted on the back) to fit a 1590B with battery.

Unverified

(http://i898.photobucket.com/albums/ac182/Scruffie_Crow/LAChorusSS.gif?t=1311710749)

(http://i898.photobucket.com/albums/ac182/Scruffie_Crow/LAChorusPCB.gif?t=1311710727)

54.61 x 52.07mm

Enjoy.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Brymus on July 26, 2011, 07:39:33 PM
cool,  :icon_cool:

edit: would an 072 be ok?..
I got a 072 to modulate as an LFO.
But no matter what type of IC or LFO I used I couldnt get the Vref to fluctuate at the 2399.
So all I got was delay.
I am waiting to get some different 2399s and try again,because I love the soundclips.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Scruffie on July 26, 2011, 08:07:09 PM
How well does this function as a vibrato, is it worth adding pads to the PCB to lift the 10k off the input out the circuit with an SPST?

Sorry if this has been answered but yeah... 35 pages to read through.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: deadastronaut on July 28, 2011, 04:38:03 AM
^ no idea , but i like the idea of having the delay option/switch too...as bryan said!..if it can be done... ;).. options!..


:just got an ne5532 to try... ;)
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: askwho69 on July 28, 2011, 09:43:23 AM
^ no idea , but i like the idea of having the delay option/switch too...as bryan said!..if it can be done... ;).. options!..


:just got an ne5532 to try... ;)

which layout did you try rob?
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Pigyboy on July 31, 2011, 05:34:15 AM
Can someone explain what R7 - 330k does in the circuit? I dropped it to 27k then 1.2k and it still works good but is way less hissy. The only problem is I need to have them boxed up to really tell it is less noisy. Going to try to jimmy-rig another in a box today to check the 330k side by side with one of a lower value R7....
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: merlinb on July 31, 2011, 05:50:26 AM
Can someone explain what R7 - 330k does in the circuit? I dropped it to 27k then 1.2k and it still works good but is way less hissy. The only problem is I need to have them boxed up to really tell it is less noisy. Going to try to jimmy-rig another in a box today to check the 330k side by side with one of a lower value R7....
It doesn't do anything,* really it should have been replaced with a wire link from the start.

*in alternative circuits it would serve to reduce the output offset of the opamp, but that is no important in this case, so it just adds noise.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Pigyboy on July 31, 2011, 05:58:22 AM
It will latch up sometimes with a straight jumper but seems to be all right with the 1.2k....I just want to hear it next to one with a 330k so hear the difference...gonna play around and post what I find.
Thanks
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: merlinb on July 31, 2011, 05:59:56 AM
It will latch up sometimes with a straight jumper but seems to be all right with the 1.2k....I just want to hear it next to one with a 330k so hear the difference...gonna play around and post what I find.
Thanks
Whatever is causing it to latch up, it isn't that resistor! It's completely unrelated to the PT.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Pigyboy on July 31, 2011, 01:08:23 PM
Ok, I changed C5 & C6 to .47uf film caps and it really cleaned everything up. I jumpered R7 - 330k and on mictesters pin 6 fix I changed R1 from 47R to 1R2 and R2 from 2K2 to 68K and it has not got hot or latched up. It still has some background but it is acceptable I think. I don't have any other chorusy type boxes here to compare it to...success!
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Pigyboy on July 31, 2011, 01:30:39 PM
Does this make sense...
I noticed when the PT latches up if I unplug it and short the +/- of the power jack then plug it back in it works every time. So I wired the red battery terminal lug of the power jack that I am not using to the ground lug. When the power jack is unplugged the + shorts to the - and resets the chip...seems to work everytime...this is using mictesters pin 6 fix set-up on the 1590A build.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Pigyboy on July 31, 2011, 01:51:03 PM
While I am thinking about it I recall people having problems with the sound being distorted or farty...I am pretty sure if you change C5 &C6 to .47uf film caps it will fix this. I have one here that sounded shite with ceramic .1's and totally cleaned up with the change. Hope this helps...
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: merlinb on July 31, 2011, 05:39:41 PM
Does this make sense...
I noticed when the PT latches up if I unplug it and short the +/- of the power jack then plug it back in it works every time. So I wired the red battery terminal lug of the power jack that I am not using to the ground lug. When the power jack is unplugged the + shorts to the - and resets the chip...seems to work everytime...this is using mictesters pin 6 fix set-up on the 1590A build.
Yes that would make sense. Mictesters fix only works provided you leave the unit unpowered for several seconds before powering up again, since the 47u doesn't discharge enough via the diode to allow immediate reset.

Also, when a PT goes into latch up once it will usually do it again even when the pin 6 resistor is more than 1k (something inside seems to burn out and it can't drive as much current at start up any more). You usually have to make it several k after that to avoid further latch ups, which explains why increasing R21 helped.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: tuckster on August 03, 2011, 03:23:19 PM
Just finished my little angel (birthday edition). The effect works butit is very subtle like Pigyboy noticed first. Any suggestions on this?
(http://thumbnails54.imagebam.com/14341/b4f723143407023.jpg) (http://www.imagebam.com/image/b4f723143407023) (http://thumbnails51.imagebam.com/14341/e9d361143407032.jpg) (http://www.imagebam.com/image/e9d361143407032)
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: askwho69 on August 04, 2011, 06:40:30 AM
Just finished my little angel (birthday edition). The effect works butit is very subtle like Pigyboy noticed first. Any suggestions on this?
(http://thumbnails54.imagebam.com/14341/b4f723143407023.jpg) (http://www.imagebam.com/image/b4f723143407023) (http://thumbnails51.imagebam.com/14341/e9d361143407032.jpg) (http://www.imagebam.com/image/e9d361143407032)
wonderful layout! mine sharing ? i like on board stuff
 :D
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: tuckster on August 04, 2011, 07:05:29 AM
Yes od course but I don't know if there are any mistakes in it. Just wanted to wait until someone found out whats the problem with the new circuit :D I only steal circuits, unfortunately I'm not able to fix designes by myself.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Pigyboy on August 09, 2011, 10:42:43 AM
Made a little discovery. All my angels always turn on without latching with the depth knob maxed. Any ideas?
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: ~arph on August 09, 2011, 10:48:13 AM
A quick question.. if it latches, does it make a terrible noise?
Could be that I'm latching up one of my builds when the modulation gets out of hand or the input signal gets too high (too much feedback)
EDIT: I'm not talking about a LA
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Pigyboy on August 09, 2011, 11:07:48 AM
^^
What are you referring to? When my angels latch they just sound a little different without the effect....and they get hot!
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: ~arph on August 09, 2011, 11:16:08 AM
^^
What are you referring to? When my angels latch they just sound a little different without the effect....and they get hot!

Cool, that's the anwser I was looking for..  I was talking about a very noisy stuck oscillation kinda problem. Now I think of it.. I think I had a similar sounding issue with my belton reverb brick.. if the input level got too high it went into horrible oscillating noise.

Sorry for the interruption, please do continue...
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: askwho69 on August 09, 2011, 02:28:06 PM
so the one knob cheap chorus needs to be look?
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: rhcp_schipper on August 11, 2011, 11:34:33 AM
Made a little discovery. All my angels always turn on without latching with the depth knob maxed. Any ideas?

Hello Everybody,

My name is Tim and Chris from el musico loco introduced me to this forum. I bought one of the Angel choruses he sells. Unfortunately the one I have has the latching problem described above. I found out that when the depth knob is maxed out and you put the power on the angel will work fine(every-time you do that). But when I have my favorite setting (both knobs approximately  at 12 o'clock), the angel will latch up.

I have allot of contact with Chris about this problem, but he said to me it is smart to post the problem here at the forum so maybe one of you guys could help us out here.

The first thing I'm going to do is putting a new PT2399 in, because maybe this is a bad chip, who knows?

Many thanks!

Tim
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Govmnt_Lacky on August 11, 2011, 11:55:22 AM
Made a little discovery. All my angels always turn on without latching with the depth knob maxed. Any ideas?

...I found out that when the depth knob is maxed out and you put the power on the angel will work fine(every-time you do that). But when I have my favorite setting (both knobs approximately  at 12 o'clock), the angel will latch up.

Has anyone bothered to probe Pin 2 of the PT to see what resistance/voltage range it falls into when it is working/latching?
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Pigyboy on August 11, 2011, 12:10:16 PM
Welcome aboard Tim!  How often is it latching?
I have one here that seems to start chorusing when I plug a 12volt adapter into it and keep chorusing when I swap it right over to a 9 volt...
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: rhcp_schipper on August 11, 2011, 12:22:47 PM
Welcome aboard Tim!  How often is it latching?
I have one here that seems to start chorusing when I plug a 12volt adapter into it and keep chorusing when I swap it right over to a 9 volt...

Mine keeps latching every time I put power on it, with my own settings! Even when I power it up at 12 volts the angel latches!

The only way to make it chorus is to max out the depth knob, and than put the power on. There is no other way.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Pigyboy on August 11, 2011, 02:00:20 PM
After you power it on with the depth maxed then it works normally?
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: rhcp_schipper on August 11, 2011, 03:02:45 PM
After you power it on with the depth maxed then it works normally?

Yes! But when I dial in my own favorite setting, and power it off and back on again, it latches! So each time I power up the Angel I have to max out the depth knob, and than bring the power on to get it working properly! After I've done this I can dial in my own settings and use it.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: sundgist on August 11, 2011, 03:29:53 PM
After you power it on with the depth maxed then it works normally?

Yes! But when I dial in my own favorite setting, and power it off and back on again, it latches! So each time I power up the Angel I have to max out the depth knob, and than bring the power on to get it working properly! After I've done this I can dial in my own settings and use it.

I read through this entire thread last night as I've just received parts to start building this.
There is a fix posted here http://www.diystompboxes.com/smfforum/index.php?topic=86297.msg774512#msg774512 (http://www.diystompboxes.com/smfforum/index.php?topic=86297.msg774512#msg774512)
There's a fair bit of info about the latching issue earlier in the thread.

[edit]
Just re-read the last few posts. Curious about this.
Also, when a PT goes into latch up once it will usually do it again even when the pin 6 resistor is more than 1k (something inside seems to burn out and it can't drive as much current at start up any more). You usually have to make it several k after that to avoid further latch ups, which explains why increasing R21 helped.

If the fix is in the build from the start, would there be any reason for it to ever latch up? Assuming (for simplicitys sake) that the cap in the fix is fully discharged between any switching off/on (accidental or otherwise) while depth is below 1k.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Pigyboy on August 11, 2011, 04:16:17 PM
All the chips seem to react different even with the fixes. Seems I read back somewhere that they work every time with a battery. Lots of the older ones seem to be fine but lately lots have been reporting iffy ones. I think Tim's discovery is on the right path....Rick!?
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: merlinb on August 11, 2011, 05:18:17 PM
If the fix is in the build from the start, would there be any reason for it to ever latch up? Assuming (for simplicitys sake) that the cap in the fix is fully discharged between any switching off/on (accidental or otherwise) while depth is below 1k.
Things are complicated by the modulation of Vref, because that also affects the internal pin 6 circuitry, so it depends on how the LFO starts up. Best bet would be to improve the latch up fix by putting the 47R resistor in series with the emitter instead of collector, and increasing the charge time (increase the 68k to 220k say). Alternatively, put a couple of diodes or an LED in series with the emitter and eliminate the 47R resistor completely; this will increase the time before the transistor starts conducting.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Pigyboy on August 11, 2011, 05:28:41 PM
Thanks Merlin,
I'll try to build a little pin 6 fix board with your suggestions. It may take me a day or two so feel free anyone else...
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: sundgist on August 11, 2011, 05:57:51 PM
Things are complicated by the modulation of Vref, because that also affects the internal pin 6 circuitry, so it depends on how the LFO starts up. Best bet would be to improve the latch up fix by putting the 47R resistor in series with the emitter instead of collector, and increasing the charge time (increase the 68k to 220k say). Alternatively, put a couple of diodes or an LED in series with the emitter and eliminate the 47R resistor completely; this will increase the time before the transistor starts conducting.

As far as I recall reading the latching only occurs at power up. Has anyone experienced it during use?

Supposing pin 2 was held at 2.5v until the cap at pin 6 had charged fully before letting the lfo do it's thing. Would this make things more foolproof?

My thinking is that this would allow the chip to start in ideal conditions.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: merlinb on August 12, 2011, 04:41:47 AM
Supposing pin 2 was held at 2.5v until the cap at pin 6 had charged fully before letting the lfo do it's thing. Would this make things more foolproof?
That would probably work, but seems overcomplicated to add start-up circuits to both pins. The whole thing can be made fool proof if the pin-6 latch up fix is improved. As it is, it's a bit borderline. The transistor+LED version I'm using works every time even with PTs I have thoroughly burnt out in the past.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: rhcp_schipper on August 13, 2011, 02:10:21 PM
Hello you guys,

Again I had a bit of a struggle with getting my angel to chorus! Even with the little fix of setting the depth to max and then power it on wouldn't help.

Now I discovered that when I put both the speed and the depth to max it will chorus like it has to do.

Thought I share with you all.

Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Gary on August 29, 2011, 12:55:01 PM
Rick (F.C.),

I built one of these (b-day edition) for our bass player, including a few mods here and there to get the sound he was looking for.

In the process, I think I've found an error in your b-day edition PnP file.  The problem appears to be R21/R22.  On the PnP, they form a divider at the collector of Q2.  According to the schematic, it should be R21 to ground off pin 6, then R22 in series to the collector of Q2.

I can verify your layout works with this corrected and adding in a couple of Merlin's tips.  (I added his suggestions of an LED on Q2 emitter and changing the 68k at Q2 base to 100k.  So far, so good.)
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: frequencycentral on August 29, 2011, 01:19:05 PM
Damn, yeah you're right. Thanks for your sharp eyes and heads up. I'll correct it ASAP.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: frequencycentral on August 29, 2011, 02:38:58 PM
Corrected: http://www.diystompboxes.com/smfforum/index.php?topic=86297.msg790099#msg790099

Refresh your cookies, pour yourself another glass of milk. If the PnP says 'RH + KH 4EVA' in the top left you're seeing the corrected layout.  ;)

Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Gary on August 29, 2011, 03:44:42 PM
Nicely done!  Thank you, Rick.  I really like your layouts.

I'd be interested to hear if this fixes the latch up issue without needing the LED on Q2's emitter.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: bhill on August 29, 2011, 06:12:42 PM
Just wanted to say thanks, Rick, for a nice piece of work. I was sitting around yesterday playing through mine, switching guitars every so often and wondering what a lfo with several waveforms to select from would sound like in this circuit. Not that it sounds bad now, I like it as well as most other choruses I have played. Just one of those occupational hazards we all go through, wondering what mods can be done and will it add that something extra to the sound we look for. Then just for the heck of it I plugged in the P-bass. Took it into the shop today and had a couple other bass players I know try it out. All our responses were the same, somewhat along the line of OMFG!! :icon_eek: Now I gotta build a couple more. :icon_smile:

Thanks Rick
Bob
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: markeebee on September 02, 2011, 09:39:56 AM
If the PnP says 'RH + KH 4EVA' in the top left.....

You plum.  Congratulations.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: frequencycentral on September 02, 2011, 11:42:12 AM
If the PnP says 'RH + KH 4EVA' in the top left.....

You plum.  Congratulations.

Plum? Peach! Thanks, it's tomorrow.  ;)
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: stash on September 09, 2011, 01:17:52 PM
Hey!

Can anyone help me?? I made little angel using following layout:

http://www.diystompboxes.com/smfforum/index.php?topic=86297.msg726268#msg726268

but all I can get out of it is clean signal with about 0,5 s delay and some noise. Any idea what's the problem.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: frequencycentral on September 09, 2011, 01:23:12 PM
If it's passing audio, and with delay too, the issue must be the LFO not working. Poke about around pins 1 to 3 of IC2, and the components in that area, as well as your wiring for the two pots, orientation of C9 and C10.....
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: stash on September 11, 2011, 01:05:45 PM
Actually there was nothing wrong except me being unable to recognize alphabet. :icon_redface: So there was 100K instead of 100R. But thanks anyway. You made me re-read the schematic. Chorus is working well.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Frances Rhodes on September 13, 2011, 08:42:38 PM
did someone try to replace the LFO section by a different function generator, something in the idea of the EHX pulsar, square wave, sawtooth, and asymmetrical setting?
i'd be curious to know how this would sound like
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: tasos on September 23, 2011, 10:41:42 AM
Hey everybody!
Did anyone tried a substitute for the pot values? 8)
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: robmdall on October 25, 2011, 01:27:10 PM
Pin 6 fix - Is this what Merlin was describing?

(http://i415.photobucket.com/albums/pp231/robmdall/Pin6Fix.jpg)
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Groovenut on October 29, 2011, 12:48:06 PM
If the fix is in the build from the start, would there be any reason for it to ever latch up? Assuming (for simplicitys sake) that the cap in the fix is fully discharged between any switching off/on (accidental or otherwise) while depth is below 1k.
Things are complicated by the modulation of Vref, because that also affects the internal pin 6 circuitry, so it depends on how the LFO starts up. Best bet would be to improve the latch up fix by putting the 47R resistor in series with the emitter instead of collector, and increasing the charge time (increase the 68k to 220k say). Alternatively, put a couple of diodes or an LED in series with the emitter and eliminate the 47R resistor completely; this will increase the time before the transistor starts conducting.
On the original the operating voltage on pin 6 was ~.7 volts. Do we need to match this voltage with the diode/LED on the emitter or can we use any generic red LED?
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: PereatMundus on November 04, 2011, 05:55:46 PM
hey hey.
So my L.A.'s been sitting halfway built for far too long now [along with (no joke) 13other pedals  :icon_redface: ]
Last package of parts arrived today thou, gonna head out and fetch em tomorrow and start finishing the projects.

So went through the thread again and as usual the info is all over the place and spread around.
Quote's below from what I reccon is the only needed info. To help next random person from reading through the
whole thread again for the X'th time.

I dont remember now but can posts here on the forum be edited "forever" ?  so the first post easily can be updated
with the newest version of the schem / layouts avalible etc?  that might [if possible] be a good thiing to do ;)

From what I can tell the pin 6 fix still is no unilateral successful fix?
the PT2399's acting somewhat different and reports beeing all over the place as to why and when it looks up.
But.. it does help thou?
[I got a few of em to try with (in a couple of other delay pedals) so hope Ill find one who works, just curious mostly]

Pin 6 fix - Is this what Merlin was describing?

(http://i415.photobucket.com/albums/pp231/robmdall/Pin6Fix.jpg)

I guess so, sort of anyway, check quote's below.

So is there an updated schematic with these fixes...?

If so I might do an Onboard Pot 1590B with room for battery PCB...

Schematic for the Birthday Edition:

(http://dl.dropbox.com/u/967492/Little%20Angel%20Miracle%203.PNG)
^^^

Well I was gonna save this as a surprise for LA's 1st birthday in August, but........

(http://dl.dropbox.com/u/967492/LA%20Birthday%20Edition/LA%20Birthday%20PCB.gif)
(http://dl.dropbox.com/u/967492/LA%20Birthday%20Edition/LA%20Birthday%20PnP.gif)

I wanted to keep it 1590A-able, but also add good things like the Pin 6 Fix and a seperate vref for the audio path. Here's the lowdown:

  • Pin 6 Fix: D1/C16/Q2/R21/R22
    I did add a little Pin 6 Fix subcircuit to a PT2399 that I know won't work without. It still has issues, but I think raising R22 to 100R and C16 to 47uF will sort it
  • Audio vref: R23/R24/C17 - suggested by merlinb as a way to reduce noise dumped into the older version's 5v vref supply by the PT2399
  • C4 changed to 3.3nF - might be a bit darker but will be less hissy
 
As it's planned to be 1590A-able, hopefully all the electro caps should be able to be bend over 900 to lie flat against the PCB. C16 might be the trickiest.

I PM'ed this layout last week to a couple of people who expressed interest in verifying it, so you never know, it could be verified within a day or so. The layout does need a little tidy up, as I notice the pad sizes are not all the same size.

mictester over at the other place has developed a little sub-circuit to prevent the PT2399 from locking up:

 "The PT2399 datasheet warns about having a low value resistor from pin 6 to ground during the power-on reset that the IC does automatically. The reset lasts 400 ms. I keep pin 6 with a higher value resistor for longer than the reset period. I tried it, and the three ICs I tried it with did not lock up. With the 2N3904 I used, the delay was pretty much identical to that from a 100R resistor. "

It would appear to be verfied twice. Should solve people's problems with some PT2399 not liking this circuit.

(http://dl.dropbox.com/u/967492/Pin6Fix.jpeg)
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Gorilla0815 on November 07, 2011, 04:21:35 PM
Hey guys,

isn't the layout wrong about C17? In the schematic, there is a 47uF cap, in the layout a 10uF. I have to say that I'm not really into this whole schematic-thing. Does it make the sound different?

I'm talking about the birthday-edition, to prevent confusion.

Greets
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: slacker on November 07, 2011, 05:01:46 PM
Yeah, you're right C17 should be 47u according to the schematic. In this case it doesn't matter, either value will do the same job, with no effect on the sound.

Welcome to the forum :)
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Gorilla0815 on November 08, 2011, 04:35:10 PM
Ok, in this case I'll continue soldering ;) Thanks!

And Thanks!  :)

Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: geiristudio on November 09, 2011, 08:14:21 PM
Hi there, I just finished putting this: http://www.sabrodesign.com/wp-content/uploads/2011/04/LittleAngelRev1.gif together and it passes audio when bypassed (duh!) and when active but nothing happens. I can hear a tiny change in the guitar tone but the knobs don't do anything and there's no chorus going on.

I tried powering on-off a few times, shorting out, powering on with the depth maxed out and everything I've read that works for some people but nothing works for me.

I've checked the circuit 5 times and it is soldered 100% like the schematic. I've made lots of pedals and all of them work.

Any update on the lock up ?
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Seven64 on November 09, 2011, 08:32:40 PM
Hi there, I just finished putting this: http://www.sabrodesign.com/wp-content/uploads/2011/04/LittleAngelRev1.gif together and it passes audio when bypassed (duh!) and when active but nothing happens. I can hear a tiny change in the guitar tone but the knobs don't do anything and there's no chorus going on.

I tried powering on-off a few times, shorting out, powering on with the depth maxed out and everything I've read that works for some people but nothing works for me.

I've checked the circuit 5 times and it is soldered 100% like the schematic. I've made lots of pedals and all of them work.

Any update on the lock up ?

i used that layout and it worked perfectly the first time, and 8mos later still hasnt locked up or anything.  check your circuit again or try a different pt2399
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: mthibeau on November 09, 2011, 10:09:04 PM
Hi there, I just finished putting this: http://www.sabrodesign.com/wp-content/uploads/2011/04/LittleAngelRev1.gif together and it passes audio when bypassed (duh!) and when active but nothing happens. I can hear a tiny change in the guitar tone but the knobs don't do anything and there's no chorus going on.

I tried powering on-off a few times, shorting out, powering on with the depth maxed out and everything I've read that works for some people but nothing works for me.

I've checked the circuit 5 times and it is soldered 100% like the schematic. I've made lots of pedals and all of them work.

Any update on the lock up ?

i used that layout and it worked perfectly the first time, and 8mos later still hasnt locked up or anything.  check your circuit again or try a different pt2399

I build that layout a few weeks ago, it does lockup from time to time, but I think that my be due to the PT2399 I used (a recent order from Tayda). The layout works great though, and when it locks up all I do is power off/on and it works again.

- MikeT
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: geiristudio on November 10, 2011, 05:18:44 AM
I'm either changing the PT2399 or building another circuit to see if it works. I'm 100% sure that the one that's locking up is correct so it might be the IC.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Seven64 on November 10, 2011, 05:41:08 AM
Hi there, I just finished putting this: http://www.sabrodesign.com/wp-content/uploads/2011/04/LittleAngelRev1.gif together and it passes audio when bypassed (duh!) and when active but nothing happens. I can hear a tiny change in the guitar tone but the knobs don't do anything and there's no chorus going on.

I tried powering on-off a few times, shorting out, powering on with the depth maxed out and everything I've read that works for some people but nothing works for me.

I've checked the circuit 5 times and it is soldered 100% like the schematic. I've made lots of pedals and all of them work.

Any update on the lock up ?

i heard an audible differance between the tayda/futurlec/smallbear pt2399's and op-amps in this circuit.  i have kept the tayda in the circuit, but admittedly i havent played on the pedal for prolonged amounts of time (prolly has <6 hrs total)

i used that layout and it worked perfectly the first time, and 8mos later still hasnt locked up or anything.  check your circuit again or try a different pt2399

I build that layout a few weeks ago, it does lockup from time to time, but I think that my be due to the PT2399 I used (a recent order from Tayda). The layout works great though, and when it locks up all I do is power off/on and it works again.

- MikeT
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: geiristudio on November 10, 2011, 02:05:10 PM
I changed the IC, no change. The circuit is definitely right in every way and nothing is touching that isn't supposed to touch. I've tried all methods posted here and nothing works.

Is there anything I can do ? This is very strange. I know how to build a pedal and this just won't work. I've done more complicated vero layouts than this.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Suicufnoc on November 21, 2011, 11:57:47 PM
Has anyone had success running this thing at 6 volts?  I'm thinking I'm gonna up the 78l05's ground reference with a diode and get about 5.7v out of it.  Probably not worth it for the 1ms less time it will get me, but I'll gain a little headroom too I guess.
Tomorrow I'll be building my vero layout with treble pre/de-emphasis and a little extra treble roll-off to kill a little hiss.  I'll post when it's verified.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: garcho on December 13, 2011, 01:02:01 AM
I breadboarded the Birthday Edition schematic tonight, it sounds awesome! It reminds me of an old Ibanez I had years ago. Thick and chewy, with lots of character. Easy to put together from that nice schematic, too. Thanks Rick! (and thanks to PTC, Small Bear, and the everyone at the forum!)
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: bluebunny on December 18, 2011, 04:08:11 PM
Just wanted to say thanks to Rick and all those who have contributed to this lengthy thread.  This was my third build (in this lifetime) and I finally got around to plugging it in and having a test run, having built the board a couple of weeks ago.  Sound came out, which is always good, but no chorusing.   :(

This is where re-reading the thread helped enormously - the more I read, the more I understood what each part of the circuit was doing.  And it became apparent that I wasn't getting any LFO to pin 2.  Lo and behold, I found a track-cut that wasn't...  :-[  (I veroed.)  Soon remedied: now I have a sweet little chorus which I am once again motivated to drill a case for!  And some ideas for mods, perhaps...

Thank you all again.  Here's to the next one!   :)
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: thedefog on December 22, 2011, 09:25:57 PM
there is an error on the layout. It says Q2 should be a 3906 pnp, but it should be a 3904 npn, correct?

Edit: guess this was updated
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: cobexonly on December 30, 2011, 03:24:46 AM
I've finished making a little angel ... and the sound is GREAT!!! .... thanks rick  :icon_cool:
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: cobexonly on January 04, 2012, 09:55:19 PM
I love the way it sound  :icon_biggrin:, but I have a little problem with LA chorus, sometimes willing to work and sometimes don't want to work .... when not working I have to unplug the power first and plug in back. And I did change the value of R1 to 1K, C1 and C3 already changed to 100nF, but still sometimes work well sometimes don't work anyway. anyone can give solution to my problem?  ???
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Barcode80 on January 05, 2012, 02:22:01 AM
a few posts up there is a circuit you can add in to prevent lockup
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: cobexonly on January 05, 2012, 06:52:36 PM
I've read from previous pages and I found to avoid the lockup from PT2399 is by substituting the value of resistor R1, capacitor C1 and C3 with the value that I mentioned above. Is there another trick that I missed? please let me know ....  ???
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: bhill on January 05, 2012, 11:20:27 PM
Don't know if anyone else has mentioned this, but if you are getting intermittent operation out of your LA, check what your power is reading. I found out the hard way on a used pedal board that someone had tried the 100r + huge cap trick for a noisy cheap wall wart that ended up with 8.1 vdc with only four pedals hooked up. At that voltage level both my LA and Echobase lfo's quit. Worked just fine when the One Spot powering the internal power strip did not get loaded down by the R/cap mentioned above. It went from 8.1 vdc to 9.54 vdc just eliminating that cludge. This worked both for the original with the pin 6 fix daughter board, and the birthday edition I built just to have everything on one board.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Barcode80 on January 06, 2012, 12:27:20 AM
I've read from previous pages and I found to avoid the lockup from PT2399 is by substituting the value of resistor R1, capacitor C1 and C3 with the value that I mentioned above. Is there another trick that I missed? please let me know ....  ???

here:

http://www.diystompboxes.com/smfforum/index.php?topic=86297.msg774512#msg774512 (http://www.diystompboxes.com/smfforum/index.php?topic=86297.msg774512#msg774512)
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: cobexonly on January 06, 2012, 11:40:30 AM
Don't know if anyone else has mentioned this, but if you are getting intermittent operation out of your LA, check what your power is reading. I found out the hard way on a used pedal board that someone had tried the 100r + huge cap trick for a noisy cheap wall wart that ended up with 8.1 vdc with only four pedals hooked up. At that voltage level both my LA and Echobase lfo's quit. Worked just fine when the One Spot powering the internal power strip did not get loaded down by the R/cap mentioned above. It went from 8.1 vdc to 9.54 vdc just eliminating that cludge. This worked both for the original with the pin 6 fix daughter board, and the birthday edition I built just to have everything on one board.

nice info bro...  I will measure voltage reading off my Power supply, and maybe I'll try to use battery first. Thanks ;)


I've read from previous pages and I found to avoid the lockup from PT2399 is by substituting the value of resistor R1, capacitor C1 and C3 with the value that I mentioned above. Is there another trick that I missed? please let me know ....  ???

here:

http://www.diystompboxes.com/smfforum/index.php?topic=86297.msg774512#msg774512 (http://www.diystompboxes.com/smfforum/index.php?topic=86297.msg774512#msg774512)

OMG  :o. how could I miss something as important as this. thanks for telling me, maybe I'll try advice from bhill first, if not successful I will try this one. thank you  :icon_wink:
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: mr_deadmaxxx on January 06, 2012, 08:55:15 PM
how is this as compared to the one-chip chorus?
http://www.diystompboxes.com/smfforum/index.php?topic=92872.0
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: mr_deadmaxxx on January 13, 2012, 04:00:33 AM
is the birthday edition verified and working?
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: bhill on January 13, 2012, 08:47:12 AM
Many times.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: juanjuin on January 25, 2012, 12:22:28 PM
excuse me
i'm a new member here
sorry for out of topic here
sorry for my bad english

i want to ask this, please
Another oops!!!!! some tipping error labeled on C6 is 0.1uF the correction is in this layout:
(http://i.imgur.com/qGgJV.gif)
Thanks Govmnt_Lacky for your observations!!! something else please!!!!!

i want to ask C12 and C14
in my country, Indonesia, i didn't find 0.1pf
is that right capasitor? i just found 1pf in electronic component store in my town,or i must make 10 of 1pf strung together a series
and is that right R1 is 100k?

sorry for my bad english
and sorry for out of topic
i was excited about 5 pot little chorus

thankyou
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: frequencycentral on January 25, 2012, 08:19:43 PM
C12 and C14 are 0.1uF (otherwise known as 100nF).

R1 is 100R (otherwise known as 100 ohm). Not 100K!
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: juanjuin on January 25, 2012, 09:16:56 PM
C12 and C14 are 0.1uF (otherwise known as 100nF).

R1 is 100R (otherwise known as 100 ohm). Not 100K!

woo, thankyou sir :)
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: mr_deadmaxxx on January 28, 2012, 10:28:24 AM
@frequency central

I built your LA Birthday Edition and I cant tell why there is a very huge amount of volume loss/drop. Around 10 to 20% only of the input signal comes out at the output. Is this normal?
BTW, I used an Ipod for the input as I dont have an electrical guitar on hand. Did that affect the volume loss?

Thanks.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: garcho on January 28, 2012, 08:12:36 PM
Quote
Around 10 to 20% only of the input signal comes out at the output. Is this normal?

No.

Quote
I used an Ipod for the input as I dont have an electrical guitar on hand. Did that affect the volume loss?

Try with a guitar before troubleshooting. Pickups are much different than what comes out of your iPod's headphone jack.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Willybomb on February 01, 2012, 06:31:11 PM
Here's mine.  It's actually my first pedal build - thanks to Haberdasher on the madbean forums for the PCB.

Gutshot (yes, it's messy):

(http://img827.imageshack.us/img827/3197/gutshot.th.jpg) (http://imageshack.us/photo/my-images/827/gutshot.jpg/)

Uploaded with ImageShack.us (http://imageshack.us)

(http://img685.imageshack.us/img685/8813/36741107.th.jpg) (http://imageshack.us/photo/my-images/685/36741107.jpg/)

Uploaded with ImageShack.us (http://imageshack.us)

(http://img3.imageshack.us/img3/4533/71795614.th.jpg) (http://imageshack.us/photo/my-images/3/71795614.jpg/)

Uploaded with ImageShack.us (http://imageshack.us)

(http://img651.imageshack.us/img651/9974/57185777.th.jpg) (http://imageshack.us/photo/my-images/651/57185777.jpg/)

Uploaded with ImageShack.us (http://imageshack.us)
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: acepepper on February 08, 2012, 09:14:42 PM
Sorry to be late to the party on this one, I don't get over here very often. Is anyone still making PCBs for the Little Angel?
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: frequencycentral on February 09, 2012, 02:33:59 AM
Is anyone still making PCBs for the Little Angel?

Yep!
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: mr_deadmaxxx on February 15, 2012, 07:32:55 AM
@chris

did your original page 4 version work ok?..still waiting to build this... :)
The one from page 9 for the 1590A's definitely works with the pin 6 fix (like the one pictured above)  I am not sure if anyone got the BDay version to work totally right yet. Turns out the sound out of mine is really weak compared to the one above.

Same problem. Weak output signal.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: frequencycentral on February 15, 2012, 07:52:55 AM
I've gotta build another one myself in a few weeks, we'll see how it turns out.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: mr_deadmaxxx on February 15, 2012, 08:13:09 AM
I guess I'll just wait then.. ;D
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: bacanador on February 15, 2012, 06:47:04 PM
I am about to build this one

I noticed one thing, that there is no capacitor to ground between the two resistors that go to the opamp on the pt2399, most circuits with the pt2399 have it, so it seems this is only a 1st order low pass filter

(http://i331.photobucket.com/albums/l457/bacanador/little-low-pass.png)


Which is equivalent to this:

(http://i331.photobucket.com/albums/l457/bacanador/little-low-pass-eq.png)


So maybe there is an opportunity to eliminate a couple of resistors, (1 at the input and 1 at the output), since it seems to work fine with a 1st order filter

I simulated this in ltspice, to make sure and I got the same freq response

Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: bacanador on February 16, 2012, 10:18:39 AM
So in other words, it would look like this

(http://i331.photobucket.com/albums/l457/bacanador/little_angel_mod.png)

I put 33K, because it is a common on value, but 30K would be the right value to keep the frequency response exacly the same. I have not tried this, but seems like it makes sense?.

I hope it is OK to use Frecuency central's artwork, (partially), I'll take it down if it is a problem
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: garcho on February 26, 2012, 10:18:34 PM
I moved this to Little Angel Space Madness Mod (http://www.diystompboxes.com/smfforum/index.php?topic=96277.0), sorry for the clutter!
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: deadastronaut on March 14, 2012, 06:21:21 AM
i'm going to breadboard this today , as it seems the most logical thing to do...

is this the final schematic with the pin 6 fix?..

http://www.diystompboxes.com/smfforum/index.php?topic=86297.msg815570#msg815570

is this a working model?...even when unplugged and plugged back in...or is there still gremlins?...cheers guys. :)


edit: hmmmm i have sound but no lfo at all :'(......ive gone over it a few times?...i'll check it over again...i hope this schematic is the working one.. :P

Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: frequencycentral on March 14, 2012, 03:04:14 PM
I built a birthday edition on Sunday, works perfectly.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: askwho69 on March 14, 2012, 10:47:07 PM
Just built in last night WORKS perfect too :D Thanks so much for this wonderful circuit simple but beautiful
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: deadastronaut on March 15, 2012, 03:54:16 AM
brilliant, cheers guys...thats good to know!....cool stuff rick!. :icon_cool:

still can't get my lfo to kick in on bread, but i'll persevere...i must be doing something weird!.. :P

btw can a rate led be attached to the opamp?...or would that mess with the lfo/sound/performance?....you know what i'm like with leds... ;D

edit got it, op amp pin 1 led.... ;)
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: garcho on March 15, 2012, 11:54:15 AM
Quote
op amp pin 1 led

Nice! I'll be adding that, too.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: deadastronaut on March 15, 2012, 12:01:42 PM
@garcho: yep!!!... :icon_cool:

i finally got it going on bread...cool.  nice one rick...

now to mod and prod it... :icon_mrgreen:

i'd like a little more depth, any depth mods?...
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: thedefog on March 15, 2012, 12:15:38 PM
Last night I lifted resistor R20 where R20 and C14 meet to make Vibrato sounds. Muddy fun! I'm guessing the angel is already maximized for optimal fidelity and minimal aliasing. Has anyone tried shifting the LPF cut-off with decent results?
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: deadastronaut on March 15, 2012, 12:25:20 PM
^ got ya, just tried that....cool.   lots of fun.  

edit: just made a clip with full depth, but changing the 33k from pin 2 of the pt....  33k/22k/10k/8.2...

http://dl.dropbox.com/u/7464107/33k22k10k8.2kchorus%20test.mp3


edit 2:

ok, been messing around again... i took that 10k vibrato mod, and swapped it out for a 33k... i also swapped the 33k from pt2399 pin 2 to a 22k...this gives a nice warble and isn't as drastic a tone change from bypass/on...
ive always noticed chorus's tend to be too bright imo...compared to bypass........anyway heres a clip... :)

http://dl.dropbox.com/u/7464107/chorustest2.mp3
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: askwho69 on March 16, 2012, 11:02:23 PM
i compare my LA in youtube my sounded too subtle? why is that? like yours rob its very subtle  not like FC's demo at 1st page
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: bluebunny on March 17, 2012, 05:15:14 PM
Finally boxed mine up that I built and tested weeks ago (birthday edition).

(http://www.bouron.org.uk/marc/LA018.JPG)

Still sounds sweet.   8)
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: rhcp_schipper on April 09, 2012, 02:55:37 PM
Hello Guys,

I have a little problem with the little angel chorus I bought from Chris(Elmusicoloco). The thing is that when I use the chorus in the fx loop of my new bought Ibanez TSA15H amp, the chorus seems to give a noticeable volume boost. I think the volume boost is there when not in the fx loop, but it is much less noticeable. Is there anyone else that has noticed this problem?

And the most important question (for me), is there a way to fix it? Asked chris, but he is to busy with business right now, and I don't have the patience.

Hope someone can help me out here.

Thanks,

Tim
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: rhcp_schipper on April 10, 2012, 12:44:26 PM
Anyone?  :icon_question:
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: garcho on April 10, 2012, 01:14:14 PM
Did you take a gander at the trouble shooting guide (http://www.diystompboxes.com/smfforum/index.php?topic=29816.0)?
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: rhcp_schipper on April 10, 2012, 02:06:48 PM
Did you take a gander at the trouble shooting guide (http://www.diystompboxes.com/smfforum/index.php?topic=29816.0)?

No, I don't. But the pedal works allright, the only problem that occurs is the volume boost when used in the fx loop.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: frequencycentral on April 10, 2012, 02:07:35 PM
Anyone?  :icon_question:

Without hacking into the PCB, voltage divider on the output. Maybe use a 100k trimmer and set it just how you like it.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: rhcp_schipper on April 10, 2012, 03:03:02 PM
Anyone?  :icon_question:

Without hacking into the PCB, voltage divider on the output. Maybe use a 100k trimmer and set it just how you like it.

Can you please be more specific. As I said I bought the pedal from chris, I didn't build it.
Would be great is I can fix this problem.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Govmnt_Lacky on April 10, 2012, 03:25:33 PM
Anyone?  :icon_question:

Without hacking into the PCB, voltage divider on the output. Maybe use a 100k trimmer and set it just how you like it.

Can you please be more specific. As I said I bought the pedal from chris, I didn't build it.
Would be great is I can fix this problem.

Set up a 100K trimmer pot in a voltage divider format to set the output to unity.

Take a 100K trimmer and connect the PCB audio output to one lug. Attach the other lug to ground. And attach the wiper to the pedal output.

Adjust to taste. Set it and forget it!  ;D

Look at how the MXR Dist+ Volume is wired here and just substitute the pot for a trimmer:

http://www.generalguitargadgets.com/pdf/ggg_dist_plus_lo.pdf?phpMyAdmin=78482479fd7e7fc3768044a841b3e85a
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: rhcp_schipper on April 10, 2012, 05:14:01 PM
Thanks! Going to try this soon. Really hope this solves the problem.
Thanks again.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: ggsmailroom on April 23, 2012, 09:07:13 AM
OK Guys, I am having a serious issue.

I built up the Perf layout (Revised for Chip hangup), and I cant find my Delay Pot Resistor anymore :(

I had it ok with the one I built before that had no revision for IC hangup, but I went back and redid it and now it works great but I cant get my delay knob back.

Any idea what I should do?

Its this layout - http://www.sabrotone.com/wp-content/uploads/2011/04/LittleAngelRev1.gif

Someone help!!!
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: deadastronaut on April 23, 2012, 09:17:21 AM
i think its a case of either/ or...

with the pin6 fix...you now lose your delay pot...which was on pin 6.....

if you try switching between the pin6bfix and a delay pot.... it makes some strange noises...and of course locks  up again...sometimes.. ::)

just the way it is i'm afraid...ive tried it....on breadboard.....

unless there is a cure for that which someone more knowledgable knows... :)
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: ggsmailroom on April 23, 2012, 09:26:55 AM
I get a kindof slap delay when I remove r8 from the circuit completely, when i add a pot here I get a semi evident delay pot, but it doesnt seem to change with even a B1m attached, you just get the same subtle like 5ms delay.

Need to get the Mix knob fixed I guess, this sucks!! I had really wanted the delay :(
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: ggsmailroom on April 23, 2012, 11:41:53 AM
Welp, here's my delayless but incredible still - Little Angel w/ Mix and Vibrato knob mods, I called 'er Squiddy :D

(http://a4.sphotos.ak.fbcdn.net/hphotos-ak-ash3/s720x720/564169_10150806648570280_677875279_12001318_1234730713_n.jpg)

Sound demo this afternoon (CST USA)
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: tasos on April 23, 2012, 02:58:59 PM
Little? ;D
Just kidding i love it so much!
Well done dude ;)
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: ggsmailroom on April 23, 2012, 09:40:58 PM
I wish I had a little angel, mines as big as a house lmao :D

Thanks!! Audio demo about to be recorded
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: garcho on April 23, 2012, 10:01:23 PM
Here's my Little Angel, with toggle switch for space madness mode (labeled 'weird'). Kinda ugly, but sounds great. Looked a lot better before I wrote on it.  :P         Thanks for the schematic Rick!

(http://a3.ec-images.myspacecdn.com/images02/144/521f832f0d404d8b94cd46da8681673f/l.jpg)
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: ggsmailroom on April 23, 2012, 11:42:32 PM
Hey Garcho thats cool! I am actually about to experiment with the spacemaddness mod on a switch, how did you do yours up??
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: ggsmailroom on April 24, 2012, 12:29:38 AM
Here's an Audio demo for the Chorus section of my Squiddy :D

CHORUS
http://soundcloud.com/garlandguitar/squiddy-chorus-clean-chorus

MIX/VIBRATO
http://soundcloud.com/garlandguitar/squiddy-chorus-mix-vibrato
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: garcho on April 24, 2012, 02:08:14 AM
A DPDT toggle switch from the base of the 2N3904 through a 22uF cap to lug 1 of the 'depth' pot. Double throw for easy LED indicator. Cheers!

(http://a4.ec-images.myspacecdn.com/images02/54/ce5136983d4b49d8a3aa47f60dd0d28e/l.png)
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: ggsmailroom on April 24, 2012, 02:20:14 AM
Excellent - now Im ready, can I use an SPDT switch if I dont want LED?
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: GodSaveMetal on April 24, 2012, 02:22:29 AM
Here's an Audio demo for the Chorus section of my Squiddy :D

CHORUS
http://soundcloud.com/garlandguitar/squiddy-chorus-clean-chorus

MIX/VIBRATO
http://soundcloud.com/garlandguitar/squiddy-chorus-mix-vibrato

Goodness amazing the sounds; like a BOUTIQUE pedal, wath changes of the RICK´s ones?? will you please a scheme; thanks!!!
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: ggsmailroom on April 24, 2012, 04:12:15 AM
Man you guys arent playing around with this Space Madness - it's an incredible Mod

I used a SPDT switch and a 10uf on this one - it sounds really awesome, push Depth to max and bring up your speed and it goes popping and squealing and the wave just goes bonkers!! Space Nightmare!! Noise lovers MUST HAVE!!!

Other side effects - Vibrato Knob on max brings out even wackier sounds on this, and the Rate slows down on normal settings when you have this engaged!! Put it to normal and your rates increase on normal settings :D

At top speed, it pops and scratches along with the beat of the rate with this kindof arpegiated pop/scratch that you can jam to, haha, I love it - on a Battery, it doesnt do this though - so fun mod, with a 9v adapter just watch out!, lower the speed for the safer range, around 70% speed sounds like an x men shooting you with plasma wave!!!

Now I need to get a DPDT and put LEDs on the Squids eyes!!!
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: ggsmailroom on April 27, 2012, 05:56:13 AM
(http://a4.sphotos.ak.fbcdn.net/hphotos-ak-prn1/s720x720/542132_10150816209435280_677875279_12027718_2133559312_n.jpg)
Space Madness!!!! :D
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Dasher on April 27, 2012, 08:33:47 PM
That Mr. Squiddy is amazing! I especially like the angry space madness eyes ;D.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: 347sixtyseven on April 30, 2012, 04:32:35 AM
This may be a silly question but here goes.

Would this circuit still work (but with a different sound) with all of the 0.1uF caps replaced with 0.082uF ones?

Cheers
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: frequencycentral on April 30, 2012, 01:55:31 PM
^^^

That'll work just fine.

BTW, can everyone who's built an Angel prease send me a $? I wanna buy Greece.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: deadastronaut on May 01, 2012, 02:33:33 AM
i have it on breadboard.....so i'll send ya $0.50.    :icon_mrgreen:
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: tasos on May 01, 2012, 04:33:13 AM
^^^

That'll work just fine.

BTW, can everyone who's built an Angel prease send me a $? I wanna buy Greece.
I don't get it! ???
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: bluebunny on May 01, 2012, 10:54:01 AM
I could send a €.

Would that be irony?  ;)



@tasos: I'm no economist, but I think it's fair to say that Greece is not in the best of financial health.  Expect to find it on an eBay listing shortly...
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: garcho on May 01, 2012, 12:50:38 PM
I'd be willing to shell out twenty bucks for a vintage Greece, say pre-Roman era.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: stringline on May 14, 2012, 04:37:42 AM
Hi there, I did Google search and found this interesting picture

(http://3.bp.blogspot.com/-D57lLcrPz98/T5Xdz4wTUnI/AAAAAAAABSI/w_ZMqM60xH0/s1600/Little+Angel+Chorus+V4.png)

I tried to build one but no modulation at all. Please advice :)
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Madness on June 14, 2012, 12:47:51 AM
Hello, I just build the project and I have a question ... hear the effect, but is very subtle, and only hear it if the potentiometers are set to 0.
If i increase the resistance of the potentiometer, the effect wears off ... From the comments I think I have a problem, can somebody help me plz?
Srry for my english.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: frequencycentral on June 14, 2012, 02:31:24 AM
@ stringline: Debugging sticky thread

@ Madness: Debugging sticky thread
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Perrow on June 14, 2012, 02:48:23 AM
@ stringline: Debugging sticky thread

@ Madness: Debugging sticky thread

Cool, this thread does echo effects now  :icon_mrgreen:
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: pinkjimiphoton on July 02, 2012, 07:34:29 PM
hey rick,
i think i have a new weirdness to report...no, i haven't read thru EVERY post of the 40 some odd pages... but i did skim thru..

i built IVIark's vero layout, for version 4 with the warble switch and the chorus/vib switch.

can't get the puppy to work, right? so i breeze thru the thread, and check for solder joint issues, etc...can't find anything. jeweler's loupe, etc etc...

then i noticed that if i disconnect the ground that goes to the emitter of the 3904, and reconnect it a couple times, eventually the whole effect fires right up, and suddenly works great.

as soon as i power down, same thing exactly happens...dead. it will pass signal if the chorus switch is in chorus mode, but only appears to pass dry signal..switch to vib mode, and it's dead.

mess with the ground, 3, 4...maybe 5 times, and suddenly there's the warble again. it is WEIRD.

i've tried 12 different 2399's, a couple plain don't work at all, some sound great, some sound mediocre. i've got the 3 best sounding ones put aside, and the best sounding in the circuit.

but the lockup thing seems to be happening, and i've checked it over and over...why the heck would i have to disconnect the ground over and over? any ideas?

could it be because i don't have it boxed yet or something?

i could really use a clue here... anybody got one?

gonna keep messing with it..thanks in advance, if anyone can figure it out!!!
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: pinkjimiphoton on July 03, 2012, 12:07:03 AM
wellp, i boxed it cuz i like it so much, but it's got issues. i tried messing with the 3904 as i read in the thread, changed the 68k to 220k....that seemed to help a little bit.
tried replacing the 47r resistor from the collector with an led from the emitter...couldn't get it to do anything that way, so put it back.

if i plug in the input jack a couple times, it will catch and work fine until it's powered down, but then if i plug it in again, i gotta plug it in several times again.

really freakin' weird...any other ideas anyone can point me at? thinking about adding another switch so i can ground/unground the ground connection...that seems to be the issue, but i'm too newb or too stupid to figure it out.

once it's working, it's absolutely astounding...beautiful toney cct, i love the warble control...it makes it sound a lot like my old clone theory sorta..

lush. sounds good even into fuzz!! ;)
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: frequencycentral on July 03, 2012, 03:08:07 AM
Hey Jim, did you catch any errors on the IVIark layout? I seem to remember some bug fixes on his forum.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: pinkjimiphoton on July 03, 2012, 11:33:21 AM
hi rick,
i went thru the whole thread at Mark's forum (alot easier than this one, a lot shorter! ;) )

i saw the bugs in the first layout he posted, but i built the full-gospel one with the anti-lock fix, as well as the chor/vib and wobble/warble switches.

i DID change the 68k resistor to 220k as merlin suggested, and tried lifting one side of the 47r resistor and replacing with an led as suggested by merlin, but then couldn't get it to work at all.

it's REALLY weird... plug it in, dead soldier unless in chorus mode, where you can hear the dry signal and it being buffered. all the voltages seem to be in the ballpark of everything i've looked at.

i tried 12 different 2399's, one was bad, all the rest worked, tho some sounded better than others. mess with the ground 4-5 times and it comes on. every time. sounds spectacular!! once it's working, you can kick the effect in or out with impunity. i left it on all nite to see if it would mess up, worked fine this morning.

sure enough, disconnect it, reconnect it and power up, dead soldier. unplug the input jack 4-5 times, and sure enough, it works again. it's almost like ya have to "trick" the chip into working...

too much mojo for the kid to figure out here!! ;)

every thing i've tried with pt2399's seems to have some kind of issue, which is a drag, cuz when they work they sound great.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: pinkjimiphoton on July 03, 2012, 11:36:46 AM
oh, almost forgot...

one thing i did find? if the effect is noisy, change out the 7805....on mine, some of the voltage regulators in my junk box made obscene amounts of noise, even ones that "seemed" to be working well... the bad ones caused hiss, weird intermittent whooshing noises, and in some cases metronome like ticking.

a good 7805 (read: brand new) fixed that.

so if anyone is having issues with noise and using junkdrawer recycles or pulls,  try a fresh one.

peace!
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: SeicheNZ on July 03, 2012, 02:19:29 PM
FIY, the new Mad Professor Electric Blue Chorus employs a PT2399 as well.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: TheVice on July 12, 2012, 02:57:54 PM
Hello fellows. My first post here. Been lurkig for a while, though  :icon_smile:

I've built this one, and my lord, is it sweet sounding. I've only got two problems with it:

1: the 3pdt switch pop! All the methods that I know have failed so far. I've added a "soft start" RC network for the LED, and pulldown resistors. I assume that's the role of R19, right? Well i've tried switching it for a 10M one, to no avail. Tried adding extra pulldown resistors to the input and otput. So far, I only built boosters / overdrives / distortions / active EQs, and tremoloes. Always tackled the pop problem. This one made me give up.
Ah, if it makes any difference, I did some mods to the original schematics: added a blend pot instead of R18, a delay pot instead of R1, decreased R13 to some.. 1k, I think, to get a deeper depth. A word of advice, anyone?

2: Some hiss showed up with the delay at max (50k pot), anyone tried this and did get rid of he hiss?


cheers.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: pinkjimiphoton on July 12, 2012, 04:42:36 PM
did you try a different 2399? some of them seem to amplify switching transients.

they really seem to have a crazy wide set of tolerances.

perhaps (newb alert) a big ass cap, say, .22 or so, in parallel with the pulldown resistor will help?
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: TheVice on July 13, 2012, 11:51:34 AM
I did try 3 other. No difference between them that I could spot. I also did try your cap-across-the-pulldown-resistor mod, although I had no idea of what this could be aimed at achieving. All i (think) I did was to direct a considerable part of the signal to ground.


@pinkjimiphoton:

try to add a electrolytic cap (200uf-2200uf), across the input terminal of the 7805 and ground. You might also try two 0.1 caps from the input and output terminals to ground (the central one). I found one day that while 7809s and 7812s can 90% times be plugged in without any extra caps, the 7805s tend to have issues, although the output voltage looks just fine. Hope this will work for you.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: pinkjimiphoton on July 13, 2012, 01:41:08 PM
diggit. i just remember using big caps in a footswitch years ago that was switching wall voltage in a homebrew leslie controller i had built.

thanks for the headsup on the 05's, i'll remember it if i run into a problem. ;)
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: TheVice on July 13, 2012, 03:25:07 PM
Right, it was you writing about the 05 as well. Thought I was answering to someone else's post. Long day,  it was  :icon_wink:
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: haveyouseenhim on July 21, 2012, 12:50:50 AM
First post here so be gentle... I made a little angel from this layout :  http://....org/viewtopic.php?f=13&t=10276

I'm losing my mind over this thing. I know i built everything right because I've gone through with a fine toothed comb many times looking for mistakes, but when i power it up its like an overdrive/distortion chorus.
Does anyone have any ideas what this could be?

I haven't read every post because its 40 something pages, but what I've read hasn't mentioned anything about overdrive/distortion being a problem.
if someone could help that would be awesome.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: haveyouseenhim on July 21, 2012, 05:57:47 AM
didn't realize i couldn't link to fsb... lets give this another try
(http://i210.photobucket.com/albums/bb292/frequencycentral/LAC1590APCB.gif)
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: frequencycentral on July 21, 2012, 06:36:23 AM
I know i built everything right because I've gone through with a fine toothed comb many times looking for mistakes, but when i power it up its like an overdrive/distortion chorus.

Your first step is to realise that you did something wrong.  ;D

Got voltages for us?
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: haveyouseenhim on July 21, 2012, 07:16:59 AM
pt2399:
1  5
2  2.45
3  0
4  0
5  2.16
6  .66
7  .82
8  .84
pins 9 - 16 are 2.45
 5532:
1 through 3 fluctuate
1  1.3 to 0
2  3 to 2
3  2.5
4  0
5  4.76
6 4.36
7  7.44
8  8.45

i was expecting that answer... i felt confident that i followed it as it shows. but apparently i goofed
any help would be greatly appreciated.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Craiz on July 23, 2012, 11:19:17 AM
Built it for a friend the other day. Absolutely gorgeous sounding....gonna have to make one for myself now (:
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: haveyouseenhim on July 23, 2012, 09:33:10 PM
 :icon_cry: Please help me Rick :icon_cry: I really want this to work.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: frequencycentral on July 24, 2012, 06:19:02 AM
Your voltages:

pt2399:
1  5
2  2.45
3  0
4  0
5  2.16
6  .66
7  .82
8  .84
pins 9 - 16 are 2.45

 5532:
1 through 3 fluctuate
1  1.3 to 0
2  3 to 2
3  2.5
4  0
5  4.76
6 4.36
7  7.44
8  8.45

My voltages:

Here are voltages just taken from my Little Angel, which sounds the same as the breadboarded version I did you soundclips on. Speed at 3 o'clock, Depth at 12 o'clock:

PT2399

1:  5
2:  2.38 to 2.42
3:  0
4:  0
5:  2.75
6:  0.61
7:  0.88
8:  0.88
9 through to 16:  2.41 (slight movement)


NE5532

1:  0.13 to 4.9
2:  2.9 to 3.2
3:  2.7 to 3.1
4:  0v
5:  4.79
6.  4.9
7:  5.14
8:  9

So it seems that your voltage at 5532 pin 7 is really high. Which would suggest either a solder bridge (migh be microscopic - scrape between the pins), or an error in the value of R7 or R15.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: haveyouseenhim on July 24, 2012, 08:00:18 AM
Ah haaaa! It was r15. I used a 10m on accident. The blue and green striped om my resistors look so much alike. I wish there was a way i could thank you besides typing these words. But thank you so much.  It sounds great   :icon_surprised:    Ive built quite a few effects, but i'm new to the whole stompbox forum thing. So its really awesome to talk directly to the designer.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: frequencycentral on July 24, 2012, 08:19:35 AM
My pleasure. Though I'm not a designer I'm a pretengineer...

BTW, I've got a few spare LA PCBs available @ £10 GBP each (including shipping).
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: haveyouseenhim on July 24, 2012, 08:31:22 AM
you're an engineer under the age of 13?   wow    lol....oh thanks, i prefer to etch my own. its more satisfying that way. I have a veggie garden and the guy next door owns a plant nursery and is always trying to sell his pre-sprouted things to me. I guess he doesn't get that i like to start with nothing but a seed.   Hmm i think i just got a little philosophical  :D
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: haveyouseenhim on July 27, 2012, 09:38:26 PM
I have an idea for a mod now that i made that pleasant mistake. I'm going to put a switch on r15 that switches between 1 and 10m. I'm going to label it good/evil. Someone try this and tel me what you think of the tone.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: haveyouseenhim on July 28, 2012, 09:13:41 PM
So through the magic of ms paint i made this:

(http://i1267.photobucket.com/albums/jj545/haveyouseenhim/LAC1590APCBwithheaven-hellmod.gif)

Basically its just switching between the 1M and 10M and the red and blue leds. Since one led draws more than the other the switch just connects the two positive leads making them steal power from each other. I'm probably going to change it to a tpdt switch so i can add some clipping diodes to smooth out the randomness of the distortion. Let me know if any of you see anything wrong with what I'm doing.

Edit: i forgot the led resistor
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: spampa on July 31, 2012, 09:58:41 AM
Hello @ all,
I´m Zottel from germany, and I´m new here at the Diystompboxes.com, but i´ve built many effects the last time.
If you are interested you can visit my Blog: http://juicypedals.blogspot.de (http://juicypedals.blogspot.de)
Now I need to build The PT 2399 little Angel "Birthday edition", but I have some trouble with the scaling when i print the PCB because it is to big.
I want to use the layout from Page 33:http://www.diystompboxes.com/smfforum/index.php?topic=86297.660 (http://www.diystompboxes.com/smfforum/index.php?topic=86297.660)
Have anyone a Adobe PDF Document with the PCB or can me help in other ways?
With kind regards, - and sorry for the bad english,
Zottel

Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: karter2000 on August 14, 2012, 03:37:09 AM
Hi all,

Just built a LA from Rick's excellent pcb.  However, I must have done something wrong as it's not working right.  I'm not getting much of a chorus effect, rather a harsh loud fuzz on every note.  The pots don't seem to do anything, and occasionally the PT2399 locks up.  I've probed around and didn't see anything blatantly wrong.  My voltages are:

NE5532:

1. 3.06
2. 3.14
3. 2.82
4. 0
5. 3.40
6. 4.27
7. 4.70
8. 9.16

PT2399:

1. 5.00
2. 2.39
3. 0
4. 0
5. 5.00
6. 0.72
7. 0
8. 4.57
9. 4.82
10. 0.38
11 2.42
12 2.42
13. 2.42
14. 4.57
15. 2.42
16. 2.42

Thanks for looking!
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: frequencycentral on August 14, 2012, 04:12:18 AM
Yours:


NE5532:

1. 3.06
2. 3.14
3. 2.82
4. 0
5. 3.40
6. 4.27
7. 4.70
8. 9.16

PT2399:

1. 5.00
2. 2.39
3. 0
4. 0
5. 5.00
6. 0.72
7. 0
8. 4.57
9. 4.82
10. 0.38
11 2.42
12 2.42
13. 2.42
14. 4.57
15. 2.42
16. 2.42

Mine:

Here are voltages just taken from my Little Angel, which sounds the same as the breadboarded version I did you soundclips on. Speed at 3 o'clock, Depth at 12 o'clock:

PT2399

1:  5
2:  2.38 to 2.42
3:  0
4:  0
5:  2.75
6:  0.61
7:  0.88
8:  0.88
9 through to 16:  2.41 (slight movement)


NE5532

1:  0.13 to 4.9
2:  2.9 to 3.2
3:  2.7 to 3.1
4:  0v
5:  4.79
6.  4.9
7:  5.14
8:  9

So it seems you have some way-off voltages at:

PT2399 pins 5, 7, 8, 9 ...you get 5V on pin 5? Pin 7 being ground is causing an issue elsewhere.

NE5532 pins 1, 2, 3 ...particularly concerning as these should be moving, which says the LFO isn't running.

NE5532 pins 5, 6, 7 ...pin 5 is way off, fix that and 6 and 7 might fall into line.

Solder bridges and/or incorrect resistor values is my guess.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Maik on August 14, 2012, 08:33:38 AM
Hello @ all,
I´m Zottel from germany, ..............................but I have some trouble with the scaling when i print the PCB because it is to big.
I want to use the layout from Page 33

Hi Zottel

die Maße sind 54,7x34,05mm
Kannste mit DIY Layout testen (Raster auf 2,54 stellen und Zeichnung (BMP) importieren...

Sorry for german, but this will go quicker then...
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: karter2000 on August 14, 2012, 12:28:01 PM

So it seems you have some way-off voltages at:

PT2399 pins 5, 7, 8, 9 ...you get 5V on pin 5? Pin 7 being ground is causing an issue elsewhere.

NE5532 pins 1, 2, 3 ...particularly concerning as these should be moving, which says the LFO isn't running.

NE5532 pins 5, 6, 7 ...pin 5 is way off, fix that and 6 and 7 might fall into line.

Solder bridges and/or incorrect resistor values is my guess.

I've checked the values of everything, and there are no solder bridges.  I'm guessing my build is really jacked beyond fixing.  Probably put it down before I smash it into a thousand pieces on my workbench.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: frequencycentral on August 14, 2012, 12:45:46 PM
Ah, the old 'smash it into a thousand pieces on my workbench' debugging technique, never fails to satisfy.  :icon_mrgreen:
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: karter2000 on August 14, 2012, 01:08:08 PM
Yeah, I promise I won't do anything drastic.  I've learned to come back to debugging after a bit of a break.  ;D

Thanks for your help Rick!
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Kunfuz on August 17, 2012, 06:11:06 AM
Got the same fuzzbuzz lawnmover action from mine sadly  :icon_frown:
Thanks for the voltages Rick, will check em out again...
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: tuckster on August 17, 2012, 07:51:51 AM
Yeah, I promise I won't do anything drastic.  I've learned to come back to debugging after a bit of a break.  ;D

Thanks for your help Rick!

Mine is in a big box of unfinished pedals :D time to get it out again I think I can fix it now......
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Jerem on August 20, 2012, 09:17:19 AM
Hi everybody, I have finished my little angel chorus but I think the output volume is too small. I want to push up the output gain so witch resistor I have to change? Thank for your answer!!
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: frequencycentral on August 20, 2012, 01:10:50 PM
Hi everybody, I have finished my little angel chorus but I think the output volume is too small. I want to push up the output gain so witch resistor I have to change? Thank for your answer!!

The output should be at unity with the input. Perhaps you have an error? How much too low is it? You could try taking voltages from your build and comparing them to mine, that way you may be able to identify where the error occurs.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Jerem on August 20, 2012, 03:44:20 PM
Thank for your answer. The sound volume is the same when I push up the volume of my gear.

I just test the Ic of the circuit :

NE5532
pin1 : 5.14v
pin2 : 4.78v
pin3 : 4.62v
pin4 : 0.5mV
pin5 : 8.74v
pin6 : 2.9v
pin7 : 2.95v
pin8 : 2.82v

PT2399

pin1 : 4.94v
pin2 : 2.38v
pin3 : 0.5mV
pin4 : 0.5mV
pin5 : 2.48v
pin6 : 0.433v
pin7 : 0.847v
pin8 : 0.849v
pin9 : 2.38v
pin10 : 2.38v
pin11 : 2.38v
pin12 : 2.38v
pin13 : 2.38v
pin14 : 2.37v
pin15 : 2.38v
pin16 : 2.38v
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: axeltrance on September 04, 2012, 06:35:07 AM
Hi to all, this is my first post.

First of all sorry for my english, i'm italian.

I made an eagle layout and board of the project, here we are:

(http://i47.tinypic.com/11qtw14.jpg)

(http://i49.tinypic.com/23mq90z.jpg)

In the next days, i made the pcb and all the rest.

If someone is interested to the Eagle files, i can post on the forum.


Bye.
Axeltrance
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: herrdoktor on September 28, 2012, 01:43:18 PM
Hi,
I finished and it works, but I've some issues
1) When I turn on the pedal I hear the oscillation of LFO in my amp
2) I hear a strange response to low frequencies (low E) with some setting of Depth and rate.

Could you say me something?
the point 1) is really important to solve.

Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: garcho on November 04, 2012, 02:49:37 AM
@Jimi P

Quote
if i plug in the input jack a couple times, it will catch and work fine until it's powered down, but then if i plug it in again, i gotta plug it in several times again.

I have the exact same issue! Figured I made a mistake somewhere so I'm about to put it back on the breadboard and try again, probably with some mods and somewhat controllable space madness (hopefully). Any up luck with the lock up?
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Unluckyfett on November 25, 2012, 08:57:01 AM
Is it possible to voice this pedal for bass? I have some ideas but Im not really certain of anything. correct me if im wrong but following the revision 2 /earthscum mod schem i would have to increase the values of the .1 caps. Would I need to increase/adjust the value of the caps/resistors on pins 9-16 of the 2399?
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: garcho on November 25, 2012, 10:31:35 AM
The caps between those pins on the PT2399 are part of a complicated filter. Changing their values will do more than a simple RC would. I've had many hours of fun experimenting with those values. Do you have a breadboard?
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Unluckyfett on November 25, 2012, 09:01:38 PM
Unfortunately i dont. I really should invest in one. when i buy the rest of the parts i do some experimenting myself. so what were your observations on changing those values?
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Unluckyfett on November 26, 2012, 02:18:23 PM
I was reading through the thread some more and found this, which i believe tells me i should be ok following that schem and the delay mod.

Aye. I've used it at 2 shows. For bass, you want to increase the delay a little bit for sure. I like the 5k pot, but already had the 10k installed.

For bass, once you find that perfect setting for you, you go from flat to gigantic godly overtones!

I used a TL072, hence the 100k pot in place of the 470k. I haven't un-ductaped my pedal to pop in an NE yet, so can't report on that. I rode my bike to the store to buy parts, came home and had it boxed and working and ready in 5 hours, with only an hour to spare before we had to be at the bar. Used it in an outdoor setting at the last one, and it is awesome. If you are outdoors, you can increase the depth a bit more without busting through over the top of the guitars.

And, lastly... absolutely no bass cut! I breadboarded mine with .022's in the audio paths, but I built it with all stock parts plus my mods to box up. I have a "super-fat" DS-1 that is basically my big OD. It increases the bass without destroying too much of the punch, still has the DS-1 grit, but bigger. This goes in front of my LA, and I only get the most minor bass cut out of it, which actually just seems to add to the overall tonal qualities.

Of all the things I tried, the ONLY one necessary for bass is the delay mod. Just a 5k pot. I wired mine so I could (next build) use the stock jumper pads from the layout. I just used a DIP strip on this one, but kept mods simple to work with the stock PCB.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: BarBandit on December 02, 2012, 09:21:33 PM
Hello everyone. I'm trying to get this layout working with the earthscum mods
http://www.diystompboxes.com/smfforum/index.php?topic=86297.560
bypass works, engaged I get a faint guitar signal with no effect and I have 100k in R1
I'm hoping someone can look at these voltages and know whats wrong
Thanks
Tim

NE5532
pin1 : 3.08-3.325v
pin2 : 3.151-3.170v
pin3 : 3.025-3.055v
pin4 : 0V
pin5 : .597v
pin6 : .877v
pin7 : 1.304v
pin8 : 9.5v

PT2399

pin1 : 5.02v
pin2 : 2.415-2.417vv
pin3 : 0V
pin4 : 0V
pin5 : 2.822v
pin6 : 2.396v
pin7 : .740v
pin8 : .812v
pin9 - 16 : 2.411-2.415v
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Perrow on December 03, 2012, 02:45:49 AM
bypass works, engaged I get a faint guitar signal with no effect and I have 100k in R1
I'm hoping someone can look at these voltages and know whats wrong
Thanks
Tim

From my own dealings with this circuit I've learned that reversing the in and out has this effect  :icon_redface:
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: BarBandit on December 03, 2012, 06:37:51 PM
bypass works, engaged I get a faint guitar signal with no effect and I have 100k in R1
I'm hoping someone can look at these voltages and know whats wrong
Thanks
Tim

From my own dealings with this circuit I've learned that reversing the in and out has this effect  :icon_redface:

Double checked it and I have it wired correctly
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: BarBandit on December 03, 2012, 09:56:15 PM
Had a loose wire and reflowed some solder now
bypass works, engaged I get a faint guitar signal with effect and I have 100k in R1
and all controls seem to work except the level pot
I'm hoping someone can look at these voltages and know whats wrong
Thanks
Tim

NE5532
pin1 : 3.08-3.325v
pin2 : 3.151-3.170v
pin3 : 3.025-3.055v
pin4 : 0V
pin5 : .597v
pin6 : .877v
pin7 : 1.304v
pin8 : 9.5v

PT2399

pin1 : 5.02v
pin2 : 2.415-2.417vv
pin3 : 0V
pin4 : 0V
pin5 : 2.822v
pin6 : 2.396v
pin7 : .740v
pin8 : .812v
pin9 - 16 : 2.411-2.415v
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: BarBandit on December 03, 2012, 10:23:28 PM
Got it going.
I made the pcb with a cnc router and it didn't complete a couple traces
don't know how many times I stared right at it and didn't see it
Sounds very cool but is pretty noisy even with the delay turned down
is there a way to filter out most of the noise?
I've tried taking out the 2399 and the noise remains
It's pretty loud hissing thats not coming from my guitar(volume down on guitar)
Thanks
Tim
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: azrael on December 04, 2012, 09:48:25 PM
I'm not a particular fan of the parts placement in that layout. C8 should be closer to pin 1. I would put a 100nF cap in parallel with it, too.
Try lifting Pin 4 from ground, by bending the leg before placing it in the IC socket. I've had problems with it working like this, but other people report a slight improvement in noise when you allow digital ground to flow through the internal 10 ohm resistor between pin 3 and 4.
a 100nF cap in parallel with C11 wouldn't hurt either.
is it in an enclosure already? once it's in a grounded enclosure, that will help a lot.
maybe shielded wire would help, too.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: BarBandit on December 04, 2012, 10:06:49 PM
I'm not a particular fan of the parts placement in that layout. C8 should be closer to pin 1. I would put a 100nF cap in parallel with it, too.
Try lifting Pin 4 from ground, by bending the leg before placing it in the IC socket. I've had problems with it working like this, but other people report a slight improvement in noise when you allow digital ground to flow through the internal 10 ohm resistor between pin 3 and 4.
a 100nF cap in parallel with C11 wouldn't hurt either.
is it in an enclosure already? once it's in a grounded enclosure, that will help a lot.
maybe shielded wire would help, too.
Awesome thanks I will try your suggestions and report back
it is in an enclosure already
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: BarBandit on December 05, 2012, 06:43:52 PM
Tried your suggestions and had no change
I guess this is just a noisy circuit. Too noisy for anything I would use it for
What would be a better choice for a chorus?
Is the zombie chorus quiet?
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: azrael on December 05, 2012, 07:51:50 PM
Oh, it sucks that it didn't improve. Have you tried a different PT2399? just wondering.
You could try building a discrete 5V regulator that's better than a 7805:
http://valvewizard2.webs.com/PT2399_Data_Notes.pdf
on page 2.
I forgot to mention, I usually use ceramic multilayer caps for the 100n decoupling, they have better qualities for this purpose, I've read.

No experience with the Zombie.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Ark Angel HFB on December 06, 2012, 10:46:11 AM
Recently I've been going way over board with my power filtering but the results of getting zero hum from what are crap but cheap wall warts has been a good thing.

no really here is the power filter that goes on the front of every pedal I build... Vin > polarity protection Diode(negative side faced toward V in) > 100 resistor > 1000uf cap to ground > 1nf cap to ground > V Out to circuit.

try the above if you can... sometimes I find the hiss from really bad power supplies doesn't drop till you get to like 220uf or even 470uf.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: garcho on December 07, 2012, 10:24:04 AM
I guess this is just a noisy circuit. Too noisy for anything I would use it for.



It's not a noisy circuit, it's a basic op amp buffer/boost. The other half of the op amp is a standard LFO. Something is wrong with your layout or components.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: BarBandit on December 10, 2012, 03:11:20 AM
Have you built this layout?
pretty noisy for me.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: garcho on December 10, 2012, 03:25:01 AM
Quote
Have you built this layout?

I've built the circuit from the schematic a number of times, no noise. Sorry, I assumed you meant the circuit was faulty, not the layout you're using, my bad.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: BarBandit on December 10, 2012, 03:43:08 AM
no worries, was just looking for confirmation that this layout was noisy
I can't seem to do anything to get rid of the hiss
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Ark Angel HFB on December 10, 2012, 09:46:46 PM
no worries, was just looking for confirmation that this layout was noisy
I can't seem to do anything to get rid of the hiss

What kind of power filtering are you using?
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: aballen on December 14, 2012, 10:54:49 PM
Hey guys. I have a copy of the birthday edition layout on page 33 post 644,  but I cant find a pdf.  I'm having trouble figuring out the scaling.

Anyone have dimensions for the board, or a dpi I can set it to for proper printing?
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: davent on December 15, 2012, 12:45:08 AM
If you have a drawing program such as Inkscape (free), open the pcb art there, set the background grid for 0.10 inches, scale the board so that the IC pads match the 0.10 inch grid. Not sure if there is a PDF available, someone else did a really nice layout for the Turkey Shootout contest, again not sure whether ther's a PDF.

dave
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: aballen on December 15, 2012, 07:40:25 PM
I got it.  I'm using Gimp.  Opening the image it seems to set it to 72 dpi, I changed that to 200 dpi, and the board prints perfect.  Already etched and drilled.  :D

I believe I read through most of the thread, and I'm hoping I can get a little more info.


Thanks for the great project, I'm so hooked on 1590a builds lately.....  Now if anyone could just come up with a good 1590a verb.


Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: gcme93 on December 26, 2012, 12:42:20 PM
Hi all,

Firstly, big props to Rick for this, thank you so much for putting the time in and giving us all something fun to make like this!

Here's the question:

http://www.sabrotone.com/wp-content/uploads/2011/04/LittleAngelRev1.gif

I'm following Sabro's great Vero layout, but haven't got a 330K resistor for R7. Is this a pretty crucial potential divider or something? Or would I be okay to sub in a 220K or 470K (which?). I honestly don't know enough about the circuit on this one :s

EDIT:

SOLVED IT MYSELF! This resistor happens to go straight over an extra line of track I left in the vero board. Hence easy enough to add two resistors (100K + 220K) to make a very close 320K.

Sorry for the unnecessary message, this is now just a "watch this space for another Little Angel project" message



Gut shots and enclosure photos to follow shortly ;)

George
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: gcme93 on January 02, 2013, 08:14:21 PM
Finished!

(http://s13.postimage.org/rqcpuntkj/pedal_front.jpg) (http://postimage.org/image/rqcpuntkj/)


(http://s7.postimage.org/x2ri24zaf/Pedal_Guts.jpg) (http://postimage.org/image/x2ri24zaf/)


Ugly as anything, but it is my first pedal, and I'm amazed that it works after only a little debugging. All the ground and live wires are different colours, the board has a few crazy diagonals on it, but ultimately it works perfectly!


Problems along the way:

1. Enclosure too small, so everything is insulated with plastic and stickers :s

2. Didn't have the right resistor at one point, made it with two in series, but made a complete mess of the board while doing so.

3. Made a solder bridge across pins 13 & 14 instead of pins 3 & 4 (confused when looking at vero layout upside down I guess)


Most useful things

1. Nick D's voltages: (very similar to mine though mine are all very slightly higher)

                                                      IC 1          1) varition from 1.4 - 7.4 ( lo-speed ) to 2.5 - 3.5 ( hi-speed )     
                                                                      2) 4.87 V
                                                                      3)  4.77 V
                                                                      4)   0.00 V
                                                                      5)  varying 2.5 - 3.5 V
                                                                      6)       "     2.5 - 3.5 V
                                                                       7)      "     1.4 - 7.8 V
                                                                      8 )  8.56 V (normal output of my PSU ) 
                                                                       

                                                      IC2             1) 5.02 V
                                                                        2) 2.5 slight wobble
                                                                        3) 0V
                                                                        4) 0 V
                                                                        5)  2.22 - 2.5 V   (didn,t spot the small variation before )
                                                                        6)  0.75 V
                                                                        7)0.66 V
                                                                        8 )  0.66 V
                                                                         9 - 16) all as pin 2 , i.e.minor variation around 2.5 V


2. Harald's vero layout and website:  http://www.sabrotone.com/?p=332  (http://www.sabrotone.com/?p=332)
     - tons of useful guides/ advice/ links etc. on that website

3. A new half decent soldering iron :)

Huge thanks to Rick for this, awesome sounding pedal. I'll upload recordings tomorrow if I have time.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: arma61 on January 14, 2013, 08:34:10 AM
Hi m8s


got a couple of questions/issue with this little gem!!

I'm talking about the very first version in this thread, build a couple of them all work good, nice chorus effects and controls act as they should, voltages look good.

First issue, cannot get rid of the hiss, I've red the whole a thread couple of time, and applied almost all the suggestions found, probably some of the Anniversary version too..  ;D (and probably understood 1% of it! :icon_redface:) The only one that worked greatly is the 0.047uF between out and gnd no hiss anymore, though there's a significant drop in signal, something like 20%. Other caps values don't produce drop in signal but don't cancel the hiss.
I've tried to recover a little bit of signal decreasing the 10k res at the opamp output, no way.

So what are the right resistors, if any, I can change to recover this 20%....

Second issue, I've tried to make it in a 1590A encl with light emitting border, using an ultrabright Blue LED hooked between OpAmp Pin 1 and gnd, to flash in time with the Rate, in this case I almost completely loose the chorus effect until I increase the Led resistor to almost 100k, in this case the LED lights up just a bit! so no use of it...
Any solution to this ?

Thanks as usual for help m8s!!

Ciao
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: mremic01 on January 16, 2013, 02:17:11 PM
I finally got around to putting together a Little Angel, the Birthday Edition. Stock it's ok, but a little dissapointing. The speed pot is only useful through the second half of it's rotation, and the depth pot through the very end. I think I'm going to switch to a b100k on the depth pot. Have you guys had the same issue with the speed pot? I might try a b50k instead of 100k. Overall, even with the depth dimed, it's still pretty subtle compared to a Small Clone or CE-2. With my CE-2, I can dial back the depth if I need to, but with the LA I can't dial in anymore, and some of the clips posted sound quite a bit more chorus'd than what I'm getting with any PT2399. After skimming through the entire thread, it sounds like some of you guys have that issue and it's not nearly as lush as the clip on page 33.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: gcme93 on January 16, 2013, 03:19:30 PM
I finally got around to putting together a Little Angel, the Birthday Edition. Stock it's ok, but a little dissapointing. The speed pot is only useful through the second half of it's rotation, and the depth pot through the very end. I think I'm going to switch to a b100k on the depth pot. Have you guys had the same issue with the speed pot? I might try a b50k instead of 100k. Overall, even with the depth dimed, it's still pretty subtle compared to a Small Clone or CE-2. With my CE-2, I can dial back the depth if I need to, but with the LA I can't dial in anymore, and some of the clips posted sound quite a bit more chorus'd than what I'm getting with any PT2399. After skimming through the entire thread, it sounds like some of you guys have that issue and it's not nearly as lush as the clip on page 33.

Hi mremic,

I'm gutted I couldn't record a sound clip before giving my LA to my cousin (21st present), but I had some pretty deep chorusing all the way up, and pretty usable speed control across the whole range (0 to 4 pretty slow, 6-8 useful and 9-10 a bit intense).

Perhaps your speed control is indicative of something wrong? I'm sure you've checked your voltages against the ones Nick D made? (I repeated them a few posts ago)

As for the depth control, there's two schools of thought on it:

1. No one's LA has depth that does much before about 50% but it having the effect on below this does make your tone warmer, and slightly doubled (not volume wise, just like to guitars playing at once) rather than chorusy

2. Those that don't like that so much have done something along the lines of 250K in series before lug one of a 250K pot: This gives you the latter stages of the depth control, but makes your total sweep the equivalent of anyone else's 50% -> 100%


Keep us updated!
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: arma61 on January 22, 2013, 07:13:59 AM
First issue, cannot get rid of the hiss, I've red the whole a thread couple of time, and applied almost all the suggestions found, probably some of the Anniversary version too..  ;D (and probably understood 1% of it! :icon_redface:) The only one that worked greatly is the 0.047uF between out and gnd no hiss anymore, though there's a significant drop in signal, something like 20%. Other caps values don't produce drop in signal but don't cancel the hiss.
I've tried to recover a little bit of signal decreasing the 10k res at the opamp output, no way.

So what are the right resistors, if any, I can change to recover this 20%....

Ciao

ok, just to report I totally got rid of the hiss with a 3n3 cap between pin 5 and gnd, no signal loss!!

Still waiting a suggestion for my 2nd issue  :icon_mrgreen:

Thx

Ciao

Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: kornerrr on March 25, 2013, 08:32:02 AM
Hi, can anybody send me correct voltages of ICs for little angel birthday edition?
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: garcho on March 25, 2013, 12:52:34 PM
From Rick a few pages back:


Quote from:
Here are voltages just taken from my Little Angel, which sounds the same as the breadboarded version I did you soundclips on. Speed at 3 o'clock, Depth at 12 o'clock:

PT2399

1:  5
2:  2.38 to 2.42
3:  0
4:  0
5:  2.75
6:  0.61
7:  0.88
8:  0.88
9 through to 16:  2.41 (slight movement)


NE5532

1:  0.13 to 4.9
2:  2.9 to 3.2
3:  2.7 to 3.1
4:  0v
5:  4.79
6.  4.9
7:  5.14
8:  9
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: kornerrr on March 25, 2013, 02:19:13 PM
These voltages that you posted are from little angel basic edition, i thought birthday edition has little different voltages, im beginner ,so i dont know much about electricity :)

i have changed 470K to 100K, my problem is i have very subtle/no chorus.

My voltages :

PT2399

1:  4.92
2:  2.45
3:  0
4:  0
5:  0.21
6:  0.86
7:  1.08
8:  1.21
9 through to 16: 2.46


NE5532

1:  1.47 to 5.3
2:  2.73
3:  2.45-2.9
4:  0v
5:  3.14
6.  3.95
7:  4.35
8:  8.50

I will be glad for any advice, thanks.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: MrStab on April 23, 2013, 02:55:11 PM
Edit: ignore this post, got it working. was either a tiny solder bridge or a slightly-loose cap. thanks anyway!  time to jam :)
hi,

my signal seems to split but not oscillate. if that makes sense. accidentally moving the floating bridge on a guitar seems to compensate for what the Little Angel isn't doing.
whilst debugging opamp A earlier, there must've been a short between vertical resistors or something, as i heard the LFO clicking (i think), but now no sign of it at all. i've swapped out PT2399 for a known working chip (and the one i removed works in a different circuit), so it doesn't seem to be that.

voltages seem okay except for the 2nd half of the TL072 i'm using - which, correct me if i'm wrong, is part of the LFO, no...? the first 4 pins function fine, but i'm picking up 2.9v on pin 5, 1.35 on 6, and up to 7.6 on pin 7. pin 8 is also fine. a lot of seemingly-random fluctuation, too, with no obvious bad joints.

any idea where i should be looking? maybe that now-elusive clicking sound from earlier could offer a clue.

 cheers!
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: kurtlives on May 13, 2013, 09:54:41 PM
What's the latest greatest version of this pedal? Schematic?
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: garcho on May 13, 2013, 11:42:26 PM
diysb wiki (http://www.diystompboxes.com/wiki/index.php?title=Little_Angel). I recommend breadboarding this and messing with it to taste, if you play mostly one guitar through one amp. Lots of fun mods, too.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Focalized on May 14, 2013, 01:26:46 AM
Built this on strip board. Really like it. Thanks for the design to who is deserving.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: kurtlives on May 14, 2013, 09:33:48 AM
diysb wiki (http://www.diystompboxes.com/wiki/index.php?title=Little_Angel). I recommend breadboarding this and messing with it to taste, if you play mostly one guitar through one amp. Lots of fun mods, too.
Cool, thanks!

What's this "Birthday Edition"?
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Vikt0r on June 04, 2013, 03:13:43 PM
This is my build. Based on the "birthday edition".
Mods include a mix/blend pot, 100K for depth (along with a 10K instead of 33K at pin 2).
(http://i1329.photobucket.com/albums/w553/ViktOr_Molnar/DSC01815_zps621614b0.jpg) (http://s1329.photobucket.com/user/ViktOr_Molnar/media/DSC01815_zps621614b0.jpg.html)
(http://i1329.photobucket.com/albums/w553/ViktOr_Molnar/DSC01807_zps53cbb6f4.jpg) (http://s1329.photobucket.com/user/ViktOr_Molnar/media/DSC01807_zps53cbb6f4.jpg.html)
(http://i1329.photobucket.com/albums/w553/ViktOr_Molnar/DSC01804_zps1352a926.jpg) (http://s1329.photobucket.com/user/ViktOr_Molnar/media/DSC01804_zps1352a926.jpg.html)
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Renegadrian on June 05, 2013, 01:00:45 PM
Quickly built my second LA those last 2 days...Great effect!
Built using standard version, vero by Sabro (it should be at page 19 if I remember correctly...) - I went straight with the 100r resistor, PT works fine...Used 2 100k-B pots. Connected a resistor (2.2k) and a LED to grd at pin 7 of the 072, nice addition! The speed LED.

Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: joshprdelac on June 11, 2013, 07:50:52 PM
Hi , i need help with my LA build.   I have problem with depth of chorus, pedal is working but chorus is subtle and is hearable only if i turn speed pot to more vibrato sound.
here are ricks voltages :
PT2399
1:  5
2:  2.38 to 2.42
3:  0
4:  0
5:  2.75
6:  0.61
7:  0.88
8:  0.88
9 through to 16:  2.41 (slight movement)

- i have on Pin5 only 0.30 to 0.90V instead of 2.75V ,the rest of pins are similar, please can somebody help me?
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Vikt0r on June 14, 2013, 09:01:51 AM
Hi!
To increase depth you may try to decrease the value of the resistor that goes to pin 2. With 10 kOhm you'll get deeper effect, i ended up
with 2.2K, although this way the depth pot affects also the speed rate of the LFO (due to LFO load impedance variation). With 33k the effect
didn't have enough depth (as for my taste).
Also you may try checking pin 5 with an oscilloscope - this is the internal clock generator output, but provided your effect works - the clock is present.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: GodSaveMetal on July 04, 2013, 09:12:34 PM
Hi!
To increase depth you may try to decrease the value of the resistor that goes to pin 2. With 10 kOhm you'll get deeper effect, i ended up
with 2.2K, although this way the depth pot affects also the speed rate of the LFO (due to LFO load impedance variation). With 33k the effect
didn't have enough depth (as for my taste).
Also you may try checking pin 5 with an oscilloscope - this is the internal clock generator output, but provided your effect works - the clock is present.

Hi, my friend please more details of your mix/blend pot; thanks a lot it is a metal chorus ehhh!!!! great!!!
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Vikt0r on July 06, 2013, 05:14:32 PM
Hi, my friend please more details of your mix/blend pot; thanks a lot it is a metal chorus ehhh!!!! great!!!
Not sure what detail do you mean..? It's a dry/wet mixing pot option. A 20K linear pot replaces R18 and R20 (according to "birthday edition" at page 33). In order to get a junction,
i moved C15 to the place of R18, C12 instead of R20. The pot is soldered to where originally C12 and C15 should have been. Watch the PCB photo - should be clear.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: psychedelicfish on July 07, 2013, 05:18:08 PM
I noticed when I was playing around with a delay on the breadboard that a capacitor from pin 5 to ground made the delay time shorter, I'm guessing it did this by increasing clock frequency... I wonder if this could be used in a chorus/flanger to get a really short delay time?
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Vikt0r on July 17, 2013, 02:54:55 AM
I noticed when I was playing around with a delay on the breadboard that a capacitor from pin 5 to ground made the delay time shorter, I'm guessing it did this by increasing clock frequency... I wonder if this could be used in a chorus/flanger to get a really short delay time?
Interesting observation. Need to check this with a scope. Will see how much this is true, considering this is the clock output and the frequency should not become affected in theory.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Paul Marossy on August 20, 2013, 03:37:34 PM
First issue, cannot get rid of the hiss, I've red the whole a thread couple of time, and applied almost all the suggestions found, probably some of the Anniversary version too..  ;D (and probably understood 1% of it! :icon_redface:) The only one that worked greatly is the 0.047uF between out and gnd no hiss anymore, though there's a significant drop in signal, something like 20%. Other caps values don't produce drop in signal but don't cancel the hiss.
I've tried to recover a little bit of signal decreasing the 10k res at the opamp output, no way.

So what are the right resistors, if any, I can change to recover this 20%....

Ciao

ok, just to report I totally got rid of the hiss with a 3n3 cap between pin 5 and gnd, no signal loss!!

That's a 0.0033uF cap, right? Curious... that's the "clock output" pin. I wonder why that works....
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: arma61 on August 21, 2013, 07:29:57 AM
First issue, cannot get rid of the hiss, I've red the whole a thread couple of time, and applied almost all the suggestions found, probably some of the Anniversary version too..  ;D (and probably understood 1% of it! :icon_redface:) The only one that worked greatly is the 0.047uF between out and gnd no hiss anymore, though there's a significant drop in signal, something like 20%. Other caps values don't produce drop in signal but don't cancel the hiss.
I've tried to recover a little bit of signal decreasing the 10k res at the opamp output, no way.

So what are the right resistors, if any, I can change to recover this 20%....

Ciao


ok, just to report I totally got rid of the hiss with a 3n3 cap between pin 5 and gnd, no signal loss!!

That's a 0.0033uF cap, right? Curious... that's the "clock output" pin. I wonder why that works....


I wonder too Paul, but it worked on that one, I have build other one with a little bit less hiss than that one (though still present) , and that 3n3 caps does almost nothing.... don't know..

Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Paul Marossy on August 21, 2013, 04:13:56 PM
First issue, cannot get rid of the hiss, I've red the whole a thread couple of time, and applied almost all the suggestions found, probably some of the Anniversary version too..  ;D (and probably understood 1% of it! :icon_redface:) The only one that worked greatly is the 0.047uF between out and gnd no hiss anymore, though there's a significant drop in signal, something like 20%. Other caps values don't produce drop in signal but don't cancel the hiss.
I've tried to recover a little bit of signal decreasing the 10k res at the opamp output, no way.

So what are the right resistors, if any, I can change to recover this 20%....

Ciao


ok, just to report I totally got rid of the hiss with a 3n3 cap between pin 5 and gnd, no signal loss!!

That's a 0.0033uF cap, right? Curious... that's the "clock output" pin. I wonder why that works....


I wonder too Paul, but it worked on that one, I have build other one with a little bit less hiss than that one (though still present) , and that 3n3 caps does almost nothing.... don't know..



Weird....  :icon_confused:
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Obier on November 05, 2013, 02:08:04 PM
Has anyone found trustworthy filtering for the PT2399?
I read a lot in this topic, but there are always new problems.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: garcho on November 06, 2013, 11:07:00 AM
Quote
Has anyone found trustworthy filtering for the PT2399?

It's a chip made for mass fabbed karaoke machines and what-have-you, don't expect to find a solution...

What do you mean by 'trustworthy'?
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: mth5044 on November 07, 2013, 06:43:46 PM
Yes - a MAX7401. Check out rring's delay on this forum and his site, circuit salad.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: pinkjimiphoton on November 11, 2013, 08:48:35 PM
found this in my ancient aol email account,
it MAY be a cure for the latchup issue... i haven't tried it yet, but figured i'd post it anyways.
fwiw, none of the other "fixes" have seemed to work for me.

anyways, from one of the gents from  bob keeley's site

Subject: Re:_Jimi_Pocius_Dot_Com

Hey Pinkster,
 
We were doing some searching for the PT2399 latch-up issues and found your problems on the tagboardeffects website  and we had the same problem as you with the latching up everytime we powered it on and only after unplugging and waiting to plug it back in did it start working again…. We may have found a fix which is a 0.01uF capacitor across pins 2 and 3 of the PT2399. Worked for us anyways.
 
Let me know if this fixes your problem!!
 
Craighton Hale
 
Keeley Electronics, Inc.
www.robertkeeley.com
1733 S. Fretz Ave. Suite C
Edmond, Oklahoma 73013
405-341-2025
 

Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: garcho on November 11, 2013, 10:32:23 PM
i wonder if that would affect the modulation? most PT2399 circuits manipulate pin 6 and have pins 2 and 3 shunted to ground, pin 2 via 47uF.

@Jimi - for what it's worth, my PT2399 builds from the last year or so, including a modded Little Angel, haven't latched up once... yet. Probably will at the worst moment possible.  :P

Quote
We were doing some searching for the PT2399 latch-up issues

If I payed 200 bucks for a chorus pedal, I'd be a little peeved if I saw a PT2399 in there. Just sayin'.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: pinkjimiphoton on November 11, 2013, 11:07:39 PM
i've had issues with every single 2399 circuit i've tried. some work.... the guitarpcb.com d'lay does...
but the one chip i've never got to work, and rick's little angel only seems to work when it wants to.
my rebote just plain DIED when i tried playing with starving it...
you can get some cool delay modulation by starving the 2399, but it has to be starved AFTER the 7805,  if ya use a normal kind of sag, it smokes the regulator.

i'm going right now to dig out my little angel build, and try the keeley fix. if it works, i'll post immediately gary
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: DEVASTATOR on December 28, 2013, 01:11:09 AM
Fack ! I really don't understand how to connect pots ! Maybe somebody can help me ?  :icon_question: :P
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Havaden on February 01, 2014, 10:08:30 AM
Hi everyone, i just made the little angel with the 1590a layout. But it won't work. :'(
I have no understanding of the PT2399 whatsoever, but i think it might be "locked"? Whatever that means?

So when i use it with no power to the circuit, the sound is weak and noisy.
When i plug in the battery, the sound gets to about the same level as without any effects and it has no noise, but no chorus either.
None of the components gets hot and i can't see anything wrong with the circuitboard. No solder bridges, nothing.

there is just no chorus, thats it. ???

I do have the 100R resistor, and i did read something about having trubles with it. But if that is the case, what should i replace it with?


By the way, this is the voltage readings of the PT2399:
1- 5V
2- 2,43V
3- 0v
4- 0v
5- 5v
6- 0,69v
7- 0v
8- 0v
9- 3,94v
10-16- 2,43v

Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Havaden on February 02, 2014, 02:29:50 PM
Nevermind, i don't know where they was, but there was some small bridges from my badly etched circuitboard.
I just made cuts between every lead, and it worked ;)
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: pulsewidthmod on March 04, 2014, 12:55:49 AM
I'm using the layout on page 8 and audio passes through but no effect. I've looked through this thread and I'm stumped. Here's my readings:


PT2399:
5.04
.83
0
0
.42
1.94
0
.74
2.52
2.34
1.16
2.52
.34
2.5
2.52
.34

TL072:
1.41
.09
.09
0
.06
5.05
9.55

Here's a photo of my build, I've made sure that all my soldering is good.

(http://f.cl.ly/items/0O0Z22203Q1Y0N1f440z/IMG_2685.jpeg)
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: toplak666 on March 06, 2014, 03:34:44 PM
I'm using the layout on page 8 and audio passes through but no effect. I've looked through this thread and I'm stumped. Here's my readings:


PT2399:
5.04
.83
0
0
.42
1.94
0
.74
2.52
2.34
1.16
2.52
.34
2.5
2.52
.34

TL072:
1.41
.09
.09
0
.06
5.05
9.55

Here's a photo of my build, I've made sure that all my soldering is good.

(http://f.cl.ly/items/0O0Z22203Q1Y0N1f440z/IMG_2685.jpeg)


And just as I was thinking that I'm the only one with this problem, the first post I see is from someone who has the exact same problem... Mine was working for a while, then after bumped the volume knob to 100% from a high gain distortion pedal I had in front of this one it stopped working. Signal passes through when it has power but there's no effect. Tried replacing both ICs for new ones with no luck. I don't know what else could be causing this... I checked for solder bridges a bunch of times already but still havent found any. Any help would be grately opreciated!

EDIT: I found this if it helps: http://puu.sh/7lolg.png
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: deadastronaut on March 07, 2014, 05:09:31 AM
yep the pt2399 likes to see at least 1k on pin 6.


or it will be prone to lock up...when powering on/off...
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: mth5044 on March 07, 2014, 04:29:30 PM
This has to have been mentioned already, but check out figure 4 and associated text on the Elliot Sound Products page for this PT2399 delay findings. Might help with the lock up.

http://sound.westhost.com/project26a.htm
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: toplak666 on March 11, 2014, 07:24:15 AM
I changed R1 to 1k and added a 10nF capacitor from pin 2 to pin 3 and it looks like that fixed it! At least one of those two things did... I don't know which. :)
I will take a good look at that link though. Might help me with any future builds. Thanks!
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Frances Rhodes on April 20, 2014, 09:25:31 AM
hey y'all

i just built a birthday edition and it works pretty good but the effect is very subtle. i didn't go throught all 46 pages (but at least half of them) so i appologize if this has already been answered before, but would it be a good idea to lower R18? or would increasing R5 be a better solution?

regards
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: miique on May 01, 2014, 06:42:01 PM
Hello everyone, I built an Echo Base delay and I'm getting a clean signal, I suspect this could be caused by the PT2399 locking up, but neither a 100R nor a 1K resistor seem to be doing the trick, can anyone tell me how to apply mictesters' Little Angel fix to the Echo Base, if I'm making any sense at all?
Title: Re:
Post by: slacker on May 02, 2014, 06:20:11 AM
To test if your Echo Base is locking up, unplug the power/battery, set the time pot to maximum resistance (longest time) and then connect power. If you still only get clean signal then your problem is not caused by it locking up. The only way the Echo Base can potentially lock up is if you start it with time pot set to very short times. No one has ever reported lock up as being a problem to me.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: garcho on May 02, 2014, 01:03:33 PM
Quote
i just built a birthday edition and it works pretty good but the effect is very subtle. i didn't go throught all 46 pages (but at least half of them) so i appologize if this has already been answered before, but would it be a good idea to lower R18? or would increasing R5 be a better solution?

i need to look at the schematic but I can tell you that this isn't a "subtle" effect - if it's built right. I really doubt that you'll need to start modding values much to get super thick chorus sound, regardless of differences in personal taste. At least PT2399 super thick, anyway. I added a blend knob to mine specifically to be able to dial some back. I'd triple check your wiring and values and solder bridges, etc. or take some voltages and post them here. I bet it's an easy fix.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Justus on August 08, 2014, 03:02:42 AM
I just built a LA Birthday Edition but, like many others, have the problem of no real effect.  I hard-wired everything with no 3PDT switch, so any problem is in the circuit for sure.  I don't see any solder bridges and all the traces look good.  Here's my voltages, which don't seem too much different from Rick's posted voltages:

PT2399

1:  5.12
2:  2.49
3:  0
4:  0
5:  0.91 - 1.00
6:  0.81
7:  0.84
8:  0.91
9 through to 16:  2.49


NE5532

1:  2.2 to 4.01
2:  2.91 to 3.05
3:  2.62 to 2.82
4:  0v
5:  3.16
6.  4.00
7:  4.13
8:  8.58


I'm running this off a battery right now.  Any idea where I should start looking with a microscope?  This is my first pedal build, ever.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: bluebunny on August 08, 2014, 03:47:54 AM
Those voltages all look pretty reasonable to me.  I would expect pin 2 of the PT2399 to show a bit of wiggle too - it's where the LFO (first half of NE5532) is going to (and that's clearly wiggling).  You might want to trace the audio path with an audio probe to see where your signal goes (and disappears?).

BTW, what layout are you using?  PCB?  Vero?  Some pictures of both sides might be helpful.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: samhay on August 08, 2014, 04:37:17 AM
The PT2399 might have latched up. Can you hear any effect?
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Justus on August 10, 2014, 01:27:54 PM
Here's the front and back (without the 78L05, as I didn't have one when I first populated the board).  The 78L05 is in there now, oriented correctly, I just don't have a new pic yet. 

I am not really hearing any effect.  I'm using an etched PCB from the latest Birthday Edition (it had the extra "4EVA" on there, but I wiped it off when I resized the image for printing so I knew which one was the right size).

(http://i1116.photobucket.com/albums/k562/JU57US/DIY%20Electronics/20140728_224402_zpsaqhikk16.jpg)

(http://i1116.photobucket.com/albums/k562/JU57US/DIY%20Electronics/20140728_224431_zpsfa3khca9.jpg)

Sorry for the delayed response, been out of town.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Frances Rhodes on August 10, 2014, 06:51:08 PM
hey y'all

has anyone tried jack orman's version of the circuit?
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Giglawyer on August 11, 2014, 03:54:01 PM
hey y'all

has anyone tried jack orman's version of the circuit?

I am in the process of starting one...just cut the vero for it last night.  It might be a  few weeks before I get to it though...got about 6 others to box up and finish first...LOL...
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: DWBH on August 11, 2014, 05:44:26 PM
I am not really hearing any effect.  I'm using an etched PCB from the latest Birthday Edition (it had the extra "4EVA" on there, but I wiped it off when I resized the image for printing so I knew which one was the right size).

I had the same happen to me.
Effect was VERY faint, and the volume was boosted when engaged, and added alot of noise.
Basically gave up on it, ordered a new PT2399 from Banzai (the ones I have were bought on ebay). I'm etching a new board later this week, but honestly I don't feel very confident I'll get it working this time :P
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Frances Rhodes on August 11, 2014, 05:50:55 PM
hey y'all

has anyone tried jack orman's version of the circuit?

I am in the process of starting one...just cut the vero for it last night.  It might be a  few weeks before I get to it though...got about 6 others to box up and finish first...LOL...

i can't have any pcb made for me so all i can do is point-to-point, the first i made took me over 15 hours to get through, but i was a little disappointed with my first angel so i want to give this other version of the circuit a try very soon
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Telvis on August 28, 2014, 01:13:37 PM
I built the original layout but it did not work, I believe that is the problem with the IC PT2399. I will build the correction suggested by pin 6 Frequency Central, hopefully solve. Can I replace the 2N3904 for a BC547?
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Mark56 on January 23, 2015, 02:52:31 PM
I appreciate nobody has posted in this thread for quite a while, but I have a suggestion to put forward and I have the seemingly unsolved problem with the PT2399 locking up.

I bought the kit from Bitsbox in the UK using the V4 vero layout from here: http://tagboardeffects.blogspot.co.uk/2012/02/little-angel-chorus-rick-holt.html and as many others have seen I have the problem with the PT2399 locking up and it does not appear to matter where the controls are set. One sure fire way of knowing the chip is locked is that it gets warm and the input current goes up from 39mA to 145mA and the voltage on pin 5 & 7 increases to over 4V. I've tried all the fixes I can find and am now waiting for a replacement PT2399. Bridging pins 2 & 3 together resets it every time.

Would it not be possible to design a circuit that will trigger a momentary short between pins 2 & 3 to reset the IC when it locks up by using the reference voltage on pin 5 or 7 as these both jump to over 4V when the IC locks up, the biggest voltage increase is on pin 7?

Creating a fix of this nature should enable any PT2399 to be used and the existing anti lock circuit could be done away with. Seems logical to me but I'm no expert, just putting forward an idea.

I appear to have a PT2399 that is particularly bad for lock ups so this would be a good one to test any viable solution on as all the other fixes I have tried fail to stop it. Increasing the 10uF cap in the anti lock circuit to 47uF made it better, but it still can't be trusted. I am prepared to try anything that is suggested. Obviously a momentary 'on' switch to short circuit pins 2 & 3 would do it, but that is of no use when playing a live gig it needs to be automatic.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: anotherjim on January 23, 2015, 04:50:17 PM
Afraid I have nothing positive to add, but am starting to get a theory of it...

2 things:
I think modulating pin 2 could be causing "crowbar" latch up of the chip. Theory is, internally, the circuits have some capacitance. Normally the reference voltage on pin2 is half supply, so about 2.5v. When the LFO raises the voltage, anything internally with 2.5v charge gets lifted with it, potentially  exceeding the power supply (2.5v+LFO increase). The same thing again to the neg supply when the LFO pulls pin 2 down. This can usually cause latch up with most MOS chips. Together with that, there could be a charge pump action going on via stray or designed PN junctions in the chip, generating excessive voltage versus supply. Since it's happening internally, you probably can't do anything about it, such as adding 2 reverse clamping diodes between pin2 and +5 and Gnd- but it could be worth a try?

The second worry, is that we don't know how much current pin6 can really, safely, sink. Recommended minimum 1k delay resistor is 2.5mA - that's about the limit for most MOS devices (such as standard gates) that aren't designed specially for higher current sinking.

Well, maybe a 3rd point, you could be too close to solar flares or the microwave...
http://en.wikipedia.org/wiki/Latchup

Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Mark56 on January 24, 2015, 04:28:22 AM
Thanks for the reply. I just about grasp what your saying, but is it even remotely possible to create an anti lock up circuit that will do as I suggested?

I will be away from my PC until Tuesday so cannot make any further replies until then.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: maiko on July 26, 2015, 08:31:36 PM
Id just like to say thanks to the guys who made this and shared it.

I built mine over the week end and it fired up right away.  I DIY'ed everything including etching the board.  Was very pleased with the result.   Got good range even if i only had 250k pot.    can only imagine when i swap it to the proper 500k

Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: frequencycentral on July 26, 2015, 11:04:36 PM
Wow! 5 years old in a couple of weeks, I wonder how many L.A.'s have been built? I just listened again to my original soundclip way back on page 1, anyone who thinks this effect is too subtle might need to check their build...
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Cozybuilder on July 27, 2015, 12:38:22 AM
Maybe a new thread for reporting completed "Little Angel" builds? I'm guessing in the thousands, I've done 2 of them.
Title: Re: &quot;Little Angel&quot; - Super Simple PT2399 Mini Chorus
Post by: bluebunny on July 27, 2015, 03:18:41 AM


Wow! 5 years old in a couple of weeks

Never mind "birthday edition", what about a "starting school" edition?  [emoji1]
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Perrow on August 04, 2015, 01:56:03 PM
I didn't build the little one, I built the little big one :)

(http://i832.photobucket.com/albums/zz249/Perrow_MLP/Builds/Little%20Big%20Angel/DSCN3552.jpg)

(http://i832.photobucket.com/albums/zz249/Perrow_MLP/Builds/Little%20Big%20Angel/LittleBigAngelLayout.png)

Only built one, yet.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Elijah-Baley on August 09, 2015, 05:40:24 AM
Excuse me, Little Angel's experts.
I have a some problem with my Little Angel building. I used tagboard vero layout. I built it some months ago, and I had a little background noise when I play (not so loud but I can hear it :(), PT2399 tipical noise, I think. I tried 3 different IC. With 2 I got no changing, and the third didn't work. I tried with another 78L05, too.
Somebody tried to help me in this forum, but I got nothing, yet.  I checked the voltage, those are ok.
I test it out of the box, without footswitch nor led indicator and with a little bit diyng battery at the moment. After boxed and with a psu this circuit could be less noisy or not?
Seems to me some demo on youtube of this pedal play noiseless.
I really don't understand this.

Another thing. I tested the circuit after much time, and just now I notice, when I set speed and, even depth pot, to zero, a quickly detune. It is normal?

Thank you!
Title: Re: &quot;Little Angel&quot; - Super Simple PT2399 Mini Chorus
Post by: Cjuried on September 15, 2015, 02:49:08 PM
I didn't build the little one, I built the little big one :)

(http://i832.photobucket.com/albums/zz249/Perrow_MLP/Builds/Little%20Big%20Angel/DSCN3552.jpg)

(http://i832.photobucket.com/albums/zz249/Perrow_MLP/Builds/Little%20Big%20Angel/LittleBigAngelLayout.png)

Only built one, yet.
Nice job!
Title: Re: &quot;Little Angel&quot; - Super Simple PT2399 Mini Chorus
Post by: Hemmel on September 15, 2015, 03:08:47 PM
I didn't build the little one, I built the little big one :)

(http://i832.photobucket.com/albums/zz249/Perrow_MLP/Builds/Little%20Big%20Angel/LittleBigAngelLayout.png)

Only built one, yet.
Nice job!

^ Agreed!
Question to Perrow: Why is pin 4 on the PT2399 bent up that way? Couldn't it be inside the socket, since the trace on the PCB doesn't go anywhere?
Title: Re: &quot;Little Angel&quot; - Super Simple PT2399 Mini Chorus
Post by: Perrow on September 15, 2015, 03:11:31 PM
The trace on the posted pcb-layout doesn't go anywhere, on the etched board it goes to ground :)
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Hemmel on September 15, 2015, 03:13:51 PM
Ah!
Got it.
Thanks!
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Perrow on September 15, 2015, 04:17:45 PM
The pcb in the build also has a turkey in the upper right corner (almost shines through on the image next to the input jack) as this was a build for the thanksgiving day contest.

It's also worth noting that the labels for the pots are wrong, should've been the other way around  ::)
Title: Re: &quot;Little Angel&quot; - Super Simple PT2399 Mini Chorus
Post by: bluebunny on September 16, 2015, 03:09:47 AM
Why is pin 4 on the PT2399 bent up that way?

I thought it was peeing...   :icon_biggrin:
Title: Re: &quot;Little Angel&quot; - Super Simple PT2399 Mini Chorus
Post by: Perrow on September 18, 2015, 05:02:48 PM
I thought it was peeing...   :icon_biggrin:

Someone has suggested it was "giving the finger", it sure is a conversation starter :D
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: GiovannyS10 on September 18, 2015, 07:09:51 PM
I built a little angel, is very nice, but i recommend you to put a volume pot, because this chorus have so much gain and is difficult to use with distortion or drive. I like drive + chorus. xD

I used this layout, worked right for me.

(http://i210.photobucket.com/albums/bb292/frequencycentral/LittleAngelPCB.gif)

Good work for you!
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: avandelay on June 12, 2016, 01:37:04 PM
Just wanted to chime in and say that I just breadboarded a Little Angel, standard edition.  Works great on first breadboard and I'm getting it ready to solder it up.  Thanks Rick!
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: dabbler on June 15, 2016, 12:58:59 PM
Over 5 years after the original design I have just, today, found the thread & have built the Little Angel (V2) on breadboard. The only change being the use of a 1K resistor on pin 6 of the PT2399. It sounds superb (particularly since it's on breadboard - no noise  8) . Unlike most like most of the people on here I'm no expert (though I have successfully built Reverb (Equinox II), Echo, Fuzz and Tremolo effects). Big thank you to Rick for this great design.

Edit: Just modified to include the pin 6 fix (so that I get 100 Ohm at pin 6 without potential for lock up) and it sounds even better! Also put a 'rate' LED  from Pin 7 of 5532 (yep, I've used opposite configuration of the dual op amp to many). Interestingly, a 3mm red LED added a bit of noise but a 3mm yellow LED is fine  ???
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: maiko on June 15, 2016, 10:08:58 PM
This is also my primary chorus.    but im wondering if i wish to increase rate and depth what mods should i first start with.   should i change the pots to smaller value?   
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Mgt280y on June 18, 2016, 06:42:19 PM
Does anyone have any prefab boards for either the little angel or birthday edition available at the moment?
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: bluebunny on June 20, 2016, 03:13:42 AM
JMK (http://jmkpcbs.com/product/little-angel/) has a board.  They're in Canada, so I assume the prices are CAD.  Works out at about £8 shipped back to the UK.  Delyk (http://pcb.delyk.com/modulation/10-little-angel-pcb.html) has a board too.  Texas this time: price is around the same.  And of course, closer to home, is Fuzz Dog (http://shop.pedalparts.co.uk/Cherub_Chorus_PCB/p847124_14307825.aspx) with their "Cherub" take on the LA: about six quid delivered.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Mgt280y on June 20, 2016, 04:35:25 AM
Cool thanks for that how does the cherub compare, as fuzz dog are awesome to deal with really fast delivery and sweets :), but all the write ups on the LA both editions sound very promising
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: roseblood11 on June 20, 2016, 05:40:37 AM
Has anyone played the original version and the improved version by Jack Orman (with 6V regulator) side by side?
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: bluebunny on June 20, 2016, 05:57:32 AM
Cool thanks for that how does the cherub compare, as fuzz dog are awesome to deal with really fast delivery and sweets :), but all the write ups on the LA both editions sound very promising

So far as I know, the Cherub is the LA (Birthday Edition), but with options for mods.  (Not to be confused with Sam's Cherub (http://www.diystompboxes.com/smfforum/index.php?topic=106854.msg968063#msg968063) chorus, btw.)
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: jfrabat on November 21, 2016, 09:06:04 PM
Hey guys!  Newbe here reviving  VERY old thread!  Sorry about that, but I need a little help!

I am building my LA, and based mine on the PCB and diagrams below (as found in Page 34 of this thread).

Schematic for the Birthday Edition:

(http://dl.dropbox.com/u/967492/Little%20Angel%20Miracle%203.PNG)

(http://dl.dropbox.com/u/967492/LA%20Birthday%20Edition/LA%20Birthday%20PCB.gif)
(http://dl.dropbox.com/u/967492/LA%20Birthday%20Edition/LA%20Birthday%20PnP.gif)

[/quote]

My first question is that it seems that C17 is 47 uF in the schematic, but the diagram has it listed as 10 uF.  I have 10 uF in mine (did not notice this until I was trouble shooting), but what should it be?  10 uF or 47 uF?  Or either one?

Now, back to trouble shooting!  Using my audio probe, I noticed that the signal is coming in strong at the input, and continues strong after C13 (0.1 uF in the schematic), but then becomes muted down after R16 (470K in the schematic). Is this normal?  It is even further muted by R15 (1M in the schematic).  This muted sound makes it all the way to the 2399 pins 14, 15 & 16...  actually, I can hear the muted sound all the way to the output.  I did not continue testing because my cell phone (my source for tones for trouble shooting) ran out of batteries, but I figured I had enough to start asking for help.  So, what do you guys suggest I look at first?  Do you need voltage readouts from the 2399 pins?
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: chuckd666 on November 21, 2016, 09:34:48 PM
I assume that cap is part of the 'separate vref' mod shown in that schematic. I'm sure either is fine - if you have trouble with 10uf I guess just replace it with 47uf.

Just had a look through the thread and this part is for the following: "Audio vref: R23/R24/C17 - suggested by merlinb as a way to reduce noise dumped into the older version's 5v vref supply by the PT2399"

Then someone said "Yeah, you're right C17 should be 47u according to the schematic. In this case it doesn't matter, either value will do the same job, with no effect on the sound."

I'm sure either will be ok.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: jfrabat on November 21, 2016, 09:56:49 PM
Great, thanks!  Now I only need to figure out why it is not actually working...
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: chuckd666 on November 22, 2016, 12:40:57 AM
I'd recommend following the troubleshooting thread and adding the necessary info like voltages on both ICs and photos etc.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Perrow on November 22, 2016, 02:37:39 AM
Great, thanks!  Now I only need to figure out why it is not actually working...

I have to say you made an excellent first post. Lots of information about your problem, even pointing out some info was missing and asking if we needed it, perfect.

No need to excuse your self for posting in this old thread, it's been revived lots of times. The thread started six years ago and while it was last alive this summer it's always nice to see it come alive  :icon_mrgreen:

Welcome to the community.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Ben Lyman on November 22, 2016, 04:29:58 PM
welcome. I am that guy that doesn't know much but always encourages people to post pics of their builds  ;D
Maybe then someone can spot something, solder bridge, wrong component, etc.

If you think the signal is getting muted way down, double check the value of the 470K. A common mistake (for me) would be to accidentally put a 4M7 right there  :P

Good luck!
Ben
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: jfrabat on November 22, 2016, 11:27:53 PM
Hey, guys!  I followed the troubleshooting guise, and, indeed, it helped.  Well, sort off...  I found the problem; the PT was not getting any power because of a bad solder joint on the leg that goes to the 5V source. 

I am attaching some pics of my build, for reference, but keep in mind, this is all prior to everything posted in this post here.  Anyway, I re-soldered the joint, and also "fixed" some others that seemed to have a similar problem (visually, anyway).  I say "Fixed" because now I get almost all the battery voltage regardless of where I probe!  Even the ground is showing 9V!  I screwed up the soldering and somewhere there is a short...  But I could not find it.  So I said screw it, and will start over again.  Now, a couple of comments:


(http://i46.photobucket.com/albums/f138/jfrabat/Guitar/Pedals/20161122_193323.jpg) (http://s46.photobucket.com/user/jfrabat/media/Guitar/Pedals/20161122_193323.jpg.html)

(http://i46.photobucket.com/albums/f138/jfrabat/Guitar/Pedals/20161122_193134_2.jpg) (http://s46.photobucket.com/user/jfrabat/media/Guitar/Pedals/20161122_193134_2.jpg.html)

Felipe
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: stallik on November 23, 2016, 02:41:26 AM
As you admit, you need some practice with soldering. The image is not clear enough for me to be 100% but I can see joints which have not been made and multiple shorts where solder has spread to the thin box surrounding the layout. There also appears to be some unmade connections
My suggestion would be to remove all of the excess solder and then re make each connection. Work slowly and use a big magnifying glass
Good luck
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: EBK on November 23, 2016, 09:27:26 AM
Quote
Yes, I am THAT bad at soldering!  Feel free to point that out!  LOL!
Check out this page to help diagnose where you are going wrong with your soldering.  It has lots of great pics, and it tells you how to repair different types of bad joints.
https://learn.adafruit.com/adafruit-guide-excellent-soldering/common-problems
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: jfrabat on November 23, 2016, 09:40:02 AM
Thanks for the link, EBK. 

I decided to start fresh.  I will also make the holes smaller on the PCB.  I used a 1/32 bit, but I think I will move to a 1/64 bit, as I find the holes are a little too big for this purpose, and that makes getting a proper solder joint right more difficult.  I mai also get a soldering iron with a better tip; the one I have is a bit hard to work with!

As for solder bridges, before the "fix" I checked with the multimeter for continuity, and there was none, and except for the bad solder at the 2399 input, the rest of the voltages seemed OK.  After the fix, I could not find any solder bridges, but I am sure at least one is there, as the voltage was wrong at many places.

As for the OpAmp, is there any issues with the switch?

Felipe
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: maiko on November 23, 2016, 07:36:39 PM
to check for solder bridges or breaks i use a flashlight with the component side underneath and the traces facing towards me
i put the flash light opossite me on the component side.  so any bridges or breaks show up .
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: bloxstompboxes on November 23, 2016, 08:49:16 PM
Choosing the right drill bit will help with the soldering. One other thing would be to watch the tarnishing of the copper traces and pads. I might be color blind but I don't see any shiny copper on that board and that makes for difficult soldering. Half the battle is knowing your handicaps and that you do. Practice and you'll be Rockin' in no time!
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: duck_arse on November 24, 2016, 09:28:09 AM
the opamp - your TL082 is the lower noise spec version of the TL072, more or less. the opamp is not doing anything terribly special or critical, so the swap should cause no bothers. if you get oscillator tikkings, you might try the 072 or the MC1458.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: jfrabat on November 24, 2016, 10:05:18 AM
Thanks for all the help, guys.  Being new to the site, I have to say you guys are a very positive group.  I like that! 

And yes, I do not have a lot of experience soldering, but in my 43 years of living (EXACTLY 43 years...  It's my B-Day today!), I have found out that practice does make a difference, so being as bull headed as I am, I will keep at it until I get it right (or at least working! LOL!)!

Couple of questions;

1. What solder wire gauge should I use?  I have 0.015" and 1.0mm at home, but the thin one (0.015") I feel is TOO thin (takes forever to get enough solder in the joint) and the thick one (1.0mm) I feel is TOO thick!  Both are 64/40, by the way...
2. I am getting a new soldering iron; the one I have is a cheap Chinese one, and I feel it's too hard to work with.  I have been doing some online research, and they say something with flat head is better to heat up both the pad and lead.  What do you guys think of the Weller WLC-100 (http://www.steren.cr/catalogo/prod.php?f=&sf=&c=&p=3775&result=cautin)?  It does not have automatic temp control, but I know Weller is suppossed to be good, and it has a flat head (and it's available locally!  That's always an issue here unless you want to wait a while for it to arrive!).
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: bloxstompboxes on November 24, 2016, 10:27:24 AM
That iron should be fine. It's the one I have, I think. As for solder wire thickness. I find that .032" is about perfect for our through hole pedal designs.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: duck_arse on November 24, 2016, 10:36:31 AM
yes, yes, never mind all that -

...... in my 43 years of living (EXACTLY 43 years...  It's my B-Day today!), .....

- will there be cake?

[manners] sorry, how rude of me: happy birthday, welcome to the forum, will there cake? [/manners]
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: jfrabat on November 24, 2016, 11:12:11 AM
yes, yes, never mind all that -

...... in my 43 years of living (EXACTLY 43 years...  It's my B-Day today!), .....

- will there be cake?

Of course!  And you are welcome to some!  It will be served at noon here in Costa Rica!
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: anotherjim on November 24, 2016, 12:05:26 PM
Quote
Even the ground is showing 9V!
Very easy mistake to make in the heat of troubleshooting is forget to plug a jack in the input - assuming you have the usual TRS jack ring to ground power switching. Then indeed, you will not have ground on the pcb.

The solder is shiny, just not flowing. Even with a narrow "pencil" point tip that I use, it's wet the tip with fresh solder, apply to joint at an angle that connects the tip to component wire and copper pad, then feed in solder (not too fast) until it flows into the joint. I find I can use a pencil tip for just about everything. If it needs more contact area, I just lay the tip so its flatter across the joint.
That really thin solder wire is tricky, it can push through the holes and cause hidden shorts. 1mm is good for general work.
If the tip ever gets loose in the barrel, an oxide layer will form which makes a heat insulator. As the metal expands and contracts, the tip will come loose, so make sure it's tight before switching it on. Take it out and polish off the oxide if necessary.

Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: jfrabat on November 27, 2016, 01:35:18 AM
Well, at least the box is coming out nicely! 

(http://i46.photobucket.com/albums/f138/jfrabat/Guitar/Pedals/20161127_002707.jpg) (http://s46.photobucket.com/user/jfrabat/media/Guitar/Pedals/20161127_002707.jpg.html)

Once the laser printer gets fixed, I will redo the PCB.  I also ordered one online as a plan B.  I WILL get this pedal working one way or the other!
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: duck_arse on November 27, 2016, 08:34:09 AM
jfrabat - your "angel" reminds me a little of [adult_content_!!] Tori Avano [/adult_content_!!]. view that content with extreme caution.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: jfrabat on December 03, 2016, 04:08:44 PM
Well, new PCB is done.  I checked for continuity, and I have it everywhere it is suppossed to be, and there is none where there should not...  I had to scratch the PCB to break a non wanted bridge, and made a couple more just to be on the safe side.  Holes are also half the size of the previous try.  Enough for the components, but with less gap.  Now its soldering time.  I hope not to screw up again.

(http://i46.photobucket.com/albums/f138/jfrabat/Guitar/Pedals/20161203_145913.jpg) (http://s46.photobucket.com/user/jfrabat/media/Guitar/Pedals/20161203_145913.jpg.html)
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: jfrabat on December 03, 2016, 05:55:16 PM
Capacitors, transistors, sockets and diode are in.  The hole size does make it easier to solder components without making a mess.  Here's how its looking prior to resistors and pots and other stuff outside the PCB:

(http://i46.photobucket.com/albums/f138/jfrabat/Guitar/Pedals/20161203_164610.jpg) (http://s46.photobucket.com/user/jfrabat/media/Guitar/Pedals/20161203_164610.jpg.html)

Definetely looking better than last one.  Gonna check continuity now before putting in resistors.  Hopefully, everything will be as it should!
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: stallik on December 03, 2016, 07:33:18 PM
Looking much better than the last one. Bit late now but you'll find it easier to solder in the components in hight order. Links, resistors and diodes first then small caps, large caps etc. Saves you struggling to hold the things in place when you solder.
You may find that a piece of sponge may help to keep the resistors in place now that the large caps are on the board
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: EBK on December 03, 2016, 08:15:44 PM
I agree that this one looks much better.  There are still a few joints that look like you didn't heat the pad on the board enough, but much progress is being made.  I hope it works when you finish.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: jfrabat on December 03, 2016, 10:29:25 PM
OK.  Finished soldering.  Signal is going through (with a bit of clean boost), but no chorus effect.  So I am further along, but not quite there yet...

Voltages read as follows (have not yet compared them to the others posted here):

IC1 (PT2399)
1. 5.03V
2. 2.50V
3. 1 mV (gonna call it 0, as even disconneed the reader shows that)
4. 1 mV (again, gonna call it 0)
5. 5.01V
6. 0.74 V
7. 151 mV and starts to go up
8. 126 mV and goes up
9 to 16. 2.51 V

IC2 (TL082)
1. 2.68 to 3.25 V (fluctuates)
2. 2.95 to 2.98 V
3. 2.78 to 2.83 V
4. 0 (1 mV)
5. 4.21 V
6. 4.34 V
7. 4.34 V
8. 8.65 V

Q1 (78L05)
In. 8.4 V
GND. 0 (1 mV)
Out. 5.01 V

Q2 (forgot to mention I replaced this one with a 2N2222A)
C: 78.4 mV
E: 1 mV
B: 0.68 V

(http://i46.photobucket.com/albums/f138/jfrabat/Guitar/Pedals/20161203_212547.jpg) (http://s46.photobucket.com/user/jfrabat/media/Guitar/Pedals/20161203_212547.jpg.html)

(http://i46.photobucket.com/albums/f138/jfrabat/Guitar/Pedals/20161203_212455.jpg) (http://s46.photobucket.com/user/jfrabat/media/Guitar/Pedals/20161203_212455.jpg.html)

Let me know if you guys spot anything out of order...

By the way, I tried replacing the PT, but readings did not change.

Felipe
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: jfrabat on December 03, 2016, 10:45:22 PM
Here are voltages just taken from my Little Angel, which sounds the same as the breadboarded version I did you soundclips on. Speed at 3 o'clock, Depth at 12 o'clock:

PT2399

1:  5
2:  2.38 to 2.42
3:  0
4:  0
5:  2.75
6:  0.61
7:  0.88
8:  0.88
9 through to 16:  2.41 (slight movement)


NE5532

1:  0.13 to 4.9
2:  2.9 to 3.2
3:  2.7 to 3.1
4:  0v
5:  4.79
6.  4.9
7:  5.14
8:  9

So it seems I have significant diferences at:
IC1, pins 5, 7 & 8
IC2, pin 7

Battery is a bit worn; did not check direct voltage, but reading from pin 8 of IC2, maybe its time for a change.  Could that be causing the issues?
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: EBK on December 04, 2016, 12:34:11 AM
I'm wondering about that copper trace across the bottom of your board that appears to disintegrate as it nears the corner.  I'd have to take a look at the original pattern vs. what you ended up with.  Haven't had time to look at your voltages though.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: anotherjim on December 04, 2016, 06:15:07 AM
PT2399 pins 5 & 6 voltages suggest the chip is "locked up". Don't worry about the 5532, it could well be ok.

Pin 5 should be somewhere around 2.5v. Actually it's a very high frequency, the clock of the delay and your meter will average it as an about halfway voltage, but this is not related to and can differ to the 2.5V found on the other pins. Pin5 either at 5v or 0v suggests the delay clock VCO isn't running.

Pin 6 is the clock VCO frequency control current. A low voltage here suggests excessive current "might" be being drawn from this pin. Possible short to 0v or too low resistance to 0v. The PT2399 clock VCO can fail to start if Pin6 resistance is less than 1k at power on. This sensitivity does vary from chip to chip. Some examples always work, some sometimes work and some never work.

Sometimes the PT2399 can lock up due to static. You can take it out and press all the pins on some metal foil for 10seconds to clear any static charge that might be in it. That bit sounds like hocus-pocus I know, but I swear it's happened to me and this trick fixed it.

Which particular LA circuit is this built to? There have been various changes to the pin6 control.
Is that PT2399 the same part used in the earlier fail?

Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: jfrabat on December 04, 2016, 09:38:03 AM
Sometimes the PT2399 can lock up due to static. You can take it out and press all the pins on some metal foil for 10seconds to clear any static charge that might be in it. That bit sounds like hocus-pocus I know, but I swear it's happened to me and this trick fixed it.

Which particular LA circuit is this built to? There have been various changes to the pin6 control.
Is that PT2399 the same part used in the earlier fail?

I will give that a shot.  The PT I started the test wit was the same one of the failed experiment.  It is the one example I found locally.  But I then replaced it with a new one I ordered from Amazon (or was it eBay?).  I would have to re check the voltages of pins 5 & 6 to be sure they are also the same still (I just woke up!), and will do so shortly.  But I will also do the metal trick just in case...

The LA is the Birthday Edition.  I will repost the schematic I followed so you guys dont tneed to search back to it.

Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: jfrabat on December 04, 2016, 09:40:23 AM
^^^

Well I was gonna save this as a surprise for LA's 1st birthday in August, but........

(http://dl.dropbox.com/u/967492/LA%20Birthday%20Edition/LA%20Birthday%20PCB.gif)
(http://dl.dropbox.com/u/967492/LA%20Birthday%20Edition/LA%20Birthday%20PnP.gif)

I wanted to keep it 1590A-able, but also add good things like the Pin 6 Fix and a seperate vref for the audio path. Here's the lowdown:

  • Pin 6 Fix: D1/C16/Q2/R21/R22
    I did add a little Pin 6 Fix subcircuit to a PT2399 that I know won't work without. It still has issues, but I think raising R22 to 100R and C16 to 47uF will sort it
  • Audio vref: R23/R24/C17 - suggested by merlinb as a way to reduce noise dumped into the older version's 5v vref supply by the PT2399
  • C4 changed to 3.3nF - might be a bit darker but will be less hissy
   
As it's planned to be 1590A-able, hopefully all the electro caps should be able to be bend over 900 to lie flat against the PCB. C16 might be the trickiest.

I PM'ed this layout last week to a couple of people who expressed interest in verifying it, so you never know, it could be verified within a day or so. The layout does need a little tidy up, as I notice the pad sizes are not all the same size.

This is the one I am using
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: jfrabat on December 04, 2016, 10:38:48 AM
Voltages of new PT after grounding all legs

1. 5.01 V
2. 2.50V
3. 1 mV
4. 1 mV
5. 5.01V
6. 0.708 V
7. 4.58 V
8. 4.58 V
9. 4.83 V
10. 0.403
11. 0.402
12. 4.78 V
13. 2.5 V
14. 0.235 V
15. 2.5V
16. 2.5 V
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: jfrabat on December 04, 2016, 10:58:10 AM
I just notice if I take the chip out, ground it, and  put it back in, pin 5 goes to 2.3V.  When that happens, pins 9 to 18 go to 2.51V and pin 7 goes to 0.434V.  But if I connect the guitar...  back to square 1.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: anotherjim on December 04, 2016, 01:39:48 PM
Ok, that really looks like the PT2399 is locking up.
I think this is the schematic...
(http://dl.dropbox.com/u/967492/Little%20Angel%20Miracle%203.PNG)

Do check R21 is 2k2 (red/red/red) and R22 is 100R (brown/black/brown) - can't see those well in the photo.

To test if it's due to too much current out of pin6, remove the 100R resistor R22 (only need to take one lead out of its hole).
Without R22, it should work but with a noticeable short time delay, which will show the PT2399 is running.

Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: jfrabat on December 04, 2016, 04:22:57 PM
I think the resistors are right:

(http://i46.photobucket.com/albums/f138/jfrabat/Guitar/Pedals/20161204_151748.jpg) (http://s46.photobucket.com/user/jfrabat/media/Guitar/Pedals/20161204_151748.jpg.html)

checked with the multimeter, resistance seems OK on both as well (98.9 ohms and 2.18K Ohms).

Here is another shot of the entire board, in case it helps figure out what wrong...

(http://i46.photobucket.com/albums/f138/jfrabat/Guitar/Pedals/20161204_151901.jpg) (http://s46.photobucket.com/user/jfrabat/media/Guitar/Pedals/20161204_151901.jpg.html)
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: stallik on December 04, 2016, 04:46:05 PM
The chip socket for the pt2399 is placed the wrong way round. The little semi circular notch should be on the left side. This is only to indicate which way round the chip should be inserted but if you haven't got that in the right way.....
Having said that, I see in a previous picture that you have the chip inserted correctly but it's worth checking
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: jfrabat on December 04, 2016, 06:00:18 PM
The chip socket for the pt2399 is placed the wrong way round. The little semi circular notch should be on the left side. This is only to indicate which way round the chip should be inserted but if you haven't got that in the right way.....
Having said that, I see in a previous picture that you have the chip inserted correctly but it's worth checking

To be honest, this is the first time I notice that notch!  LOL!  Nothing like the bliss of ignorance, right?  But the chip I did insert the right way, so I do not think that is the cause.

As for the voltage, I took out my trusty multi-meter, and went to check resistances...  Got some surprises.  Here's the resistor list with what should be in and what I measured:

                       Listed Value                Measured Value
R1                           68K                           66.6K
R2                           10K                           9.53K
R3                           10K                           9.84K
R4                           10K                           9.80K
R5                           10K                           9.79K
R6                           10K                           9.77K
R7                           330K                           321K
R8                           47K                           318K
R9                           100K                   39.7K
R10                           220K                   Did not get a measurement
R11                           220K                   212K
R12                           4.7K                      4.6K
R13                           33K                           66.6K
R14                           100K                   97.8K
R15                           1M                           2.09M
R16                           470K                   462K
R17                           10K                           9.79K
R18                           10K                           9.80K
R19                           1M                           Did not get a measurement
R20                           10K                           9.79K
R21                           2.2K                           2.18K
R22                           100                           98.8
R23                           10K                           9.20K
R24                           10K                           9.32K

The ones that have no measure is because I was getting no indication on the multi-meter.  Correct me if I am wrong, but:
47K = Yellow-Violet-Orange
100K = Brown-Black-Yellow
Is this right?  If so, I got the right resistors in place for R8 and R9, right?

I did notice that the 1M resistors I accidentally put 2.2M resistors, but I also noticed my 2,2M resistors have resistance all over the place (from 700K to 3M!).  I also have the wrong resistor for R13, so I have to swap out 3 resistors and see what's up with the other 2.  Does this sound about right?
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: anotherjim on December 05, 2016, 06:22:35 AM
You might have to tried to measure resistance with power on? It has to be power off for that, and preferably with IC's removed as they can make connections to other parts of the circuit. Also any capacitors must have time after power off to discharge.

It can take a noticeable time for resistance readings to "resolve" to a true value when there are significantly large value capacitors also connected, because the meters own test voltage supply will have to charge the capacitor as well as inject its test current through the part you are measuring. You will notice then that if you reverse the meter probes , it will first have to discharge the capacitor then recharge it to the reverse polarity, taking even longer to resolve. For the small value capacitors, this can be too fast to notice, but with the larger ones over 1uF, it's a handy way to tell if it is acting like a capacitor should. Incidentally, you cannot damage an electrolytic capacitor if you connect the meter resistance test to it with wrong polarity as there is very little current.

Ideally, resistors should have at least one leg lifted out of contact so it can be measured without the rest of circuit affecting the reading, but that is tedious unless you have a good idea that its value is wrong. So we probe around with the resistors in circuit and when we find something that looks wrong, we unsolder one end and test again to be sure.

I've a suspicion that there is nothing seriously wrong with your resistors. Do check if it works without R22. If it still don't work, try again without Q2. If it still don't work, replace R21 with something higher like 47k - there should be a really obvious delayed signal out of the PT2399. If there still isn't -  it's a bad PT2399.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: bluebunny on December 05, 2016, 08:29:33 AM
You can't really measure resistors in-circuit.  The chances that a resistor has no DC connection to anything else is slim.  As Jim says, lift a leg and measure (with the power off - that would really upset your DMM!).  Ideally, measuring resistors is something you do before you assemble.   :)
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: jfrabat on December 05, 2016, 09:24:47 AM
Thanks, guys.  So this means that R8 and R9 are correct.  I still need to change R15, R19 (the two 1M ones, which are the green ones in the photos, which I used 2.2M instead of 1M) and R13 (I put a 68K resistor by mistake).  Could these 3 resistors be the cause of my problems?

Here are the resistors in the schematic and in the picture:

(http://i46.photobucket.com/albums/f138/jfrabat/Guitar/Pedals/Bad%20Resistors%202.jpg) (http://s46.photobucket.com/user/jfrabat/media/Guitar/Pedals/Bad%20Resistors%202.jpg.html)

(http://i46.photobucket.com/albums/f138/jfrabat/Guitar/Pedals/Bad%20Resistors.jpg) (http://s46.photobucket.com/user/jfrabat/media/Guitar/Pedals/Bad%20Resistors.jpg.html)

33K should be Orange Orange Orange (obviusly it is not! Blue Gray Orange is 68K) and 1M (the green resistors) should be Red Black Green, and these are Red Red Green (2.2M)

I will try removing R22 tonight, and see how it goes.  But out of the 2 PT2399 I have tested, none have worked (different sources).  I have 4 additional PT's I can test as well.  Is it worth swapping it out at this time?  The 2399 is already out at this time...
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: anotherjim on December 05, 2016, 10:52:27 AM
Keep unused PT2399 to one side for now. If a fault is damaging them, you don't want to kill them all.
Apart from a typo just then, 1M is brown/black/green, you're reading the resistors correctly.

As you have spare PT2399, you might consider something like the Deep Blue delay next, which also requires one, but doesn't press the chip to its highest speed range. Then you can check if all the PT2399's you have are basically functional before throwing them out.

68k instead of 33k for R13 means the chorus effect won't go as deep or obvious as it should be. If you don't have 33k, solder another 68k across the existing one.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: stallik on December 05, 2016, 01:58:48 PM
Nice one Jim, I was just wondering how low the effect would be with that change to R13. The depth pots 470k so I wouldn't have thought it would remove the effect completely
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: anotherjim on December 05, 2016, 02:55:42 PM
I don't think 68k would stop it and will be surprised if it turns out to be the main fault, although it would be nice if that was all there was to it. ;)
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: jfrabat on December 05, 2016, 02:57:02 PM
Keep unused PT2399 to one side for now. If a fault is damaging them, you don't want to kill them all.
Apart from a typo just then, 1M is brown/black/green, you're reading the resistors correctly.

Sorry for the typo; you are right.  And you make a good point about the PT2399's...

As you have spare PT2399, you might consider something like the Deep Blue delay next, which also requires one, but doesn't press the chip to its highest speed range. Then you can check if all the PT2399's you have are basically functional before throwing them out.

Actually, I was considering building an Equinox II Reverb (http://www.diystompboxes.com/smfforum/index.php?topic=93868.0) (it uses 2 PT2399), but the delay is not a bad option...  I think a reverb is a bit more useful than a delay, so I's going that way.  But theoretically (assuming the PT2399's are still good to go and not toasted!), I should have 3 of them left over, which makes the delay a very good possibility for the next build (even if the 2 used PT's are bad, I still have enough)!  Still, before either, I have to get my Vulcan Rat (http://www.diystompboxes.com/smfforum/index.php?topic=116171.0) off the breadboard and into a box!

68k instead of 33k for R13 means the chorus effect won't go as deep or obvious as it should be. If you don't have 33k, solder another 68k across the existing one.

I will switch all 3 resistors (I just got some 33K's, so no problem there) tonight and test.  If it does not work, I will take R22 out and try.  If THAT does not work, then I will take the transistor out.  If it STILL does not work, then I will replace R21 with a 47K as suggested.  I will report back tonight...

Nice one Jim, I was just wondering how low the effect would be with that change to R13. The depth pots 470k so I wouldn't have thought it would remove the effect completely

You know, now that you mention it, I think I am actually using a 500K pot, not a 470K...  Just because I could not find any 470K locally.  I will double check when I get back home tonight!  But it should not make that much of a difference, right?

I don't think 68k would stop it and will be surprised if it turns out to be the main fault, although it would be nice if that was all there was to it. ;)

So what's your gut telling you?  If you had to give your best guess, what would you say it's happening?

Thanks!

Felipe
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: anotherjim on December 05, 2016, 05:31:53 PM
My gut say's the PT2399's are locking up because they don't like the 100R timing resistor.
A little backstory.
A chorus effect needs a variable delay, but it can't be such a long delay that it sounds like echo. Ideally, that's not much longer than 20ms. To get delay that in that range, the PT2399 needs to be run with a very fast clock speed. That clock is controlled by pin6 with a resistor connected to ground. The smaller that resistor is, the shorter the delay is.

It's beginning to look like recent (maybe in the last 3 years) chips run faster in the sub 1k delay resistor range than originally and cannot work with them as small as 100R as it makes them try to run faster than they can.
In the LA design, Q2 together with a 68k and 47uF  have been added. The gives a time delay after power-on which allows the chip to start with the larger 2k2 resistor. Then when the cap has charged enough to switch Q2 on, it gets full speed with the 100R. This is because the PT2399 data sheet states that the pin6 resistor should not be less than 1k when power is applied.

Pots have a wide value tolerance. Measure some for fun. It's easily possible to have a 470k that is higher value than one marked as 500k. Generally, most electronics works fine if components are within +/-10% and once upon a time production circuits had to make do with 20% components. If a circuit needs a very close tolerance part, such as 1% resistors, the drawing/BOM will ask for it.


Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: jfrabat on December 05, 2016, 09:10:55 PM
Resistors have been replaced.  Nothing.  Disconnected R22.  Still nothing.  Replaced PT back to the original.  Nothing.  Voltage readings with R22 unplugged:

Pin 1: 4.97V
Pin 2: 2.48V
Pin 3: 0V
Pin 4 : 0V
Pin 5: 2.73V (IMPROVEMENT!)
Pin 6: 2.4V (PROBLEM!)
Pin 7: 0.461V
Pin 8: 0.520V
Pins 9 to 16: 2.51V (with slight movement)

I do not see any obvious solder bridges near the PT:

(http://i46.photobucket.com/albums/f138/jfrabat/Guitar/Pedals/20161205_200519.jpg) (http://s46.photobucket.com/user/jfrabat/media/Guitar/Pedals/20161205_200519.jpg.html)

And here are the new resistors in place, in case hou spot something off (R22 is removed on purpose):

(http://i46.photobucket.com/albums/f138/jfrabat/Guitar/Pedals/20161205_200710.jpg) (http://s46.photobucket.com/user/jfrabat/media/Guitar/Pedals/20161205_200710.jpg.html)

Help is always appreciated!

Felipe
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: jfrabat on December 05, 2016, 11:55:31 PM
By the way, prior to taking out R22, the PT was getting pretty hot..  about as hot as when you touch a joint after soldering.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: chuckd666 on December 06, 2016, 12:42:33 AM
Felipe I think at this point it might be best to get out your multimeter and do a continuity check on every trace around the PT - sometimes when you make a PCB you can get cuts in the trace that aren't visible and can only be discovered by use of a multimeter.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: EBK on December 06, 2016, 01:24:51 AM
Felipe,
I just want you to know that I'm still following this thread, silently cheering you on.  I really want this pedal to work.  :icon_smile:
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: bluebunny on December 06, 2016, 03:02:06 AM
the PT was getting pretty hot

It's locking up, and probably toast.  Throw it in the bin.  (Although Pink Jimi claims he can bring them back to life!)  This is down to the resistance at pin 6 being way too low, as Jim has said.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: anotherjim on December 06, 2016, 05:44:15 AM
Quote
Pin 1: 4.97V
Pin 2: 2.48V
Pin 3: 0V
Pin 4 : 0V
Pin 5: 2.73V (IMPROVEMENT!)
Pin 6: 2.4V (PROBLEM!)
Pin 7: 0.461V
Pin 8: 0.520V
Pins 9 to 16: 2.51V (with slight movement)
These value might (only might) indicate the chip is ok. There could be another problem.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: jfrabat on December 06, 2016, 09:16:38 AM
Felipe I think at this point it might be best to get out your multimeter and do a continuity check on every trace around the PT - sometimes when you make a PCB you can get cuts in the trace that aren't visible and can only be discovered by use of a multimeter.

I did this before soldering components, but I will do it again to be sure all signals that are supposed to be there are, and those that are not are not there.  I think I will also measure voltages without the PT in.  Maybe I am getting voltage from somewhere else and that's messing things up?

Felipe,
I just want you to know that I'm still following this thread, silently cheering you on.  I really want this pedal to work.  :icon_smile:

Thanks!

Quote
Pin 1: 4.97V
Pin 2: 2.48V
Pin 3: 0V
Pin 4 : 0V
Pin 5: 2.73V (IMPROVEMENT!)
Pin 6: 2.4V (PROBLEM!)
Pin 7: 0.461V
Pin 8: 0.520V
Pins 9 to 16: 2.51V (with slight movement)
These value might (only might) indicate the chip is ok. There could be another problem.

Yeah, I don't think it's toast either.  It may be, but it is not going into the trash bin until I can confirm that it is...

OK, so my next steps should be:

1. Checking voltage at the socket (without PT in) to make sure no voltage from outside is hitting pin 6
2. Checking continuity
3. Taking out Q2
4. Swapping R21 to a 47K

Is this right?

By the way, when I connect the guitar, I can hear the guitar playing; there is just no chorus effect of any kind.  There is just a tiny little bit of clean boost.  So it seems the problem is in the lower half of the schematic...
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: anotherjim on December 06, 2016, 11:43:26 AM
It might help to take out R20 (10k). That will disconnect the dry feed to the output then any sound your hear MUST have come from the PT2399. It may help to know that audio out of the chip first comes out from pin 12. It will also be found on pin 14.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: jfrabat on December 06, 2016, 12:17:57 PM
It might help to take out R20 (10k). That will disconnect the dry feed to the output then any sound your hear MUST have come from the PT2399. It may help to know that audio out of the chip first comes out from pin 12. It will also be found on pin 14.

OK, so, the process to follow tonight is:

1. Disconnect R20 (one pin, just to break the dry feed from the output). 
2. Checking voltage at the socket (without PT in) to make sure no voltage from outside is hitting pin 6
3. Checking continuity
4. Taking out Q2
5. Swapping R21 to a 47K

Is this correct?

I am posting the schematics and layout for anyone in the future who needs it as reference to troubleshooting...

(http://dl.dropbox.com/u/967492/LA%20Birthday%20Edition/LA%20Birthday%20PCB.gif)

(http://dl.dropbox.com/u/967492/Little%20Angel%20Miracle%203.PNG)



Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: anotherjim on December 06, 2016, 12:57:08 PM
Yes, and check the op-amp pin 1 with slow speed pot to see there is a constantly changing voltage to prove the LFO is running. At full depth you should hear a strong pitch warble as well as the delay.

Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: jfrabat on December 06, 2016, 01:12:24 PM
Yes, and check the op-amp pin 1 with slow speed pot to see there is a constantly changing voltage to prove the LFO is running.

You lost me there...  can you expand on this one?
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: anotherjim on December 06, 2016, 03:38:23 PM
Pin1 of the 5532 should have a constantly changing voltage. This wobbles the voltage on Pin2 of the 2399 and causes the delay time to rise and fall. It is the reason for the cyclic effect of a chorus. The speed of it is s l o w  - low-frequency-oscillator - you shouldn't hear it directly. On the slowest speed setting, it's easier to see on the DMM. On fastest, the meter won't keep up but might show an average voltage instead. At any rate, it should never appear stuck at a high or low voltage.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: jfrabat on December 06, 2016, 03:51:43 PM
And I assume it is the same on the TL082 I amnusing instead of the 5532, right?  Or could that be the issue?
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: anotherjim on December 06, 2016, 04:44:13 PM
082 should work just the same.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: jfrabat on December 06, 2016, 05:11:28 PM
OK, got it.  Now, from what I read in your 2 previous post, in slow speed, a Digital Multi Meter should be able to pick up the oscillation, but in high speed, it will not.  Now, the only issue is that I am not sure which way is slow and which is fast on my pot, as I can't test it because there is no chorus effect (I am sure there is a way, I just don't know it!).  Usually I wire pots, try them, and if I need to, I invert #1 & #3 to get them moving the right way...  Yeah, I know, that's probably not the best way to do it, but that's what I have done so far (I have only made 2 pedals, and one I still need to re-do because it sounds awful!).

So if I put it in a mid level, will the DMM be able to pick it up?
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: jfrabat on December 07, 2016, 12:14:19 AM
Disconnect R20 (one pin, just to break the dry feed from the output).

No sound coming out

Checked voltage at the socket (without PT in) to make sure no voltage from outside is hitting pin 6

Voltage was OK

3. Checking continuity

All the leads that are suppossed to have continuity check out.  Also cleaned up some areas where I had a bit of continuity where there was none suppossed to be.

Measured voltage at pin 1 of 082

Varies from under 1V to over 5V

Voltage readings at PT:

1. 5.03V
2. 2.50V
3. 0V
4. 0V
5. 1.95V
6. 2.43V
7. 0.311V
8. 0.496V
9-16: 2.51V (starts a bit higher and comes down)

Put in a fresh PT.  Not much changes (except voltage at pins 5 and 6 increase slightly).  Put old PT back in.

I am officially stuck!  I still got plan C (the printed board from Canada), but that has taken FOREVER to arrive at the freight forwarder in Miami!  Anyway, what else should I check?

Remove the transistor?
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: bluebunny on December 07, 2016, 03:21:45 AM
Is the PT still getting hot?
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: jfrabat on December 07, 2016, 07:57:29 AM
I did not leave the pedal onas long as I did yesterday, so I am not 100% sure, but it did get warm.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: bluebunny on December 07, 2016, 08:20:46 AM
There's no reason for it to get warm, other than locking up.  Do check out the parts connected to pin 6.  Did you try lifting the 100R resistor (I think Jim suggested this earlier)?  It should definitely stay cold with only the 2K2 connecting it to ground.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: jfrabat on December 07, 2016, 09:44:47 AM
R22 (100R) and R20 (to break the dry feed from the output) are disconnected.  Just to clarify, it is not getting hot in any way, shape or form; it is just slightly warm (normal temperature for any IC).  It is not COLD, but it is not hot.  But there is no signal getting through (with the dry feed disconnected). 

Tomorrow (I can't work on it tonight) I will go through it once more.  Maybe use the Audio Probe to see where the sound is going out...  Not sure still what I should do.  But definitely, the problem is in the wet signal.  The dry signal is working just fine (well, it was before I pulled R20!).

Now, I know it is not the PT (or at least, not ONLY the PT) because I tried with a fresh one.

Pin #            Freq.Ctrl. V                    Felipe V                     Felipe NEW PT V
Pin 1            5V                                 5.03V                        5.03V
Pin 2            2.38V to 2.42V                2.50V                       2.50V
Pin 3            0V                                 0V                             0V
Pin 4            0V                                 0V                             0V
Pin 5            2.75V                            1.95V                         2.45V
Pin 6            0.61V                            2.43V                         2.43V
Pin 7            0.88V                            0.311V                       0.641V
Pin 8            0.88V                            0.496V                       0.816V
Pin 9 to 16   2.41 (slight movement)   2.51V (starts higher)   2.51V (starts higher)   

Obviously the problem is coming from PIN 6.  I also do not get oscillation in PIN 2 (I put the final reading, but it does move when I connect the reader for the first time).
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: jfrabat on December 08, 2016, 10:10:06 PM
Well, on to Plan C...  I just got my JMK PCB for the little angel.  Gonna use it for the third try.  Third time's the charm, right?   At least I got to improve my soldering skills with the prior tries!

(http://i46.photobucket.com/albums/f138/jfrabat/Guitar/Pedals/IMG_20161208_223222.jpg) (http://s46.photobucket.com/user/jfrabat/media/Guitar/Pedals/IMG_20161208_223222.jpg.html)

Is it me, or it ALMOST looks A LITTLE better than my homemade PCB?
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: anotherjim on December 09, 2016, 06:42:44 AM
The moment of truth? Breath is bated.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: bluebunny on December 09, 2016, 07:33:52 AM
Is it me, or it ALMOST looks A LITTLE better than my homemade PCB?

You can hardly tell the difference...   ;)
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: jfrabat on December 09, 2016, 11:51:03 PM
Hey, guys, could what I was experiencing be due to using 10 nF instead of 100 nF capacitors in 2 places?  Building Plan C, I noticed I had more 103 caps than what I used in the new build and 2 104 caps missing.  Could this the the reason it was not working?  I do not know which caps were wrong, as I had already taken out the ones off the previous board... 

By the way, the board is coming along nicely.  My soldering skills are also improving (I feel this PCB is easier to solder than the home made ones; maybe the double side thing?  Or maybe the new temperature controlled Weller iron?).

AND THE AWARD FOR THE MOST IMPROVEMENT IN SOLDERING IN 2016 GOES TO...

(http://i46.photobucket.com/albums/f138/jfrabat/Guitar/Pedals/IMG_20161209_222036.jpg) (http://s46.photobucket.com/user/jfrabat/media/Guitar/Pedals/IMG_20161209_222036.jpg.html)

(http://i46.photobucket.com/albums/f138/jfrabat/Guitar/Pedals/IMG_20161209_222054.jpg) (http://s46.photobucket.com/user/jfrabat/media/Guitar/Pedals/IMG_20161209_222054.jpg.html)

Anyway, this is where we are at as of tonight.  Tomorrow I have to buy some ceramic 104 caps (only got poly ones, and they do not fit well in the PCB), and attach the pots and leads and then is off to sound test!

Speaking of capacitors, what is the main difference between ceramic and Poly?  When should I use which?

Oh, and I am missing one resistor, and I need help figuring this out.  In the build manual it says R2 is CLR.  What the heck does that even mean?  All the others have values...
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: EBK on December 10, 2016, 05:46:39 AM

Speaking of capacitors, what is the main difference between ceramic and Poly?  When should I use which?

Oh, and I am missing one resistor, and I need help figuring this out.  In the build manual it says R2 is CLR.  What the heck does that even mean?  All the others have values...

Another thread where I gave my take on caps: http://www.diystompboxes.com/smfforum/index.php?topic=116096.msg1074164#msg1074164

CLR is a Current Limiting Resistor for an LED.  Value is generally not critical.  Try 4.7k, perhaps if your circuit doesn't specify.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: anotherjim on December 10, 2016, 09:24:06 AM
There are often 4x 100n (or about that value) around the PT2399. I and I'm sure many others have experimented with the values. I think having lower values makes the sound noisier & grittier. I don't recall it causing total failure.

Probably too late to suggest leaving out the pin 6 100R and the dry feed mix resistor (different part numbering on this pcb?).
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: jfrabat on December 10, 2016, 09:27:52 AM
There are often 4x 100n (or about that value) around the PT2399. I and I'm sure many others have experimented with the values. I think having lower values makes the sound noisier & grittier. I don't recall it causing total failure.

Probably too late to suggest leaving out the pin 6 100R and the dry feed mix resistor (different part numbering on this pcb?).


I can always desolder them.  Do you think its worth a shot?  It's not like I can finish the board without the missing caps, which I need to get later on.


Another thread where I gave my take on caps: http://www.diystompboxes.com/smfforum/index.php?topic=116096.msg1074164#msg1074164

CLR is a Current Limiting Resistor for an LED.  Value is generally not critical.  Try 4.7k, perhaps if your circuit doesn't specify.

Oh, OK.  I do have a 4.7k already next to the LED.  Which brings another interesting subject up; all my grounds are connected in the wiring, but the PCB has grounds for the DC jack, switch LED and Audio jack.  I only have one ground coming in.  I should use the DC jack one, right?  Or is it better to undo what I have and wore everytbing to the PCB?  Similarly, the LED is wired directly to the sqitch with its own resistor.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: jfrabat on December 10, 2016, 10:01:56 AM
One more question; in the schematics, the pots only use pins 2 & 3 (well, I always assumed "n/c" stood for "not connected; I could be wrong!) but here they are connecting all of them to the PCB.  Should I wire them up?
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: EBK on December 10, 2016, 10:29:15 AM
N/C is "not connected".  Generally, however, we would tie that extra pin 1 to pin 2.  Won't change anything though.

As far as grounding goes, there and endless opinions on the topic.  There are definitely some wrong ways to ground things, but otherwise there is a wide murky swamp of "proper" and "good enough". I personally prefer tying all my grounds to the DC jack rather than to the PCB, but I tend to shy away from telling others they should do the same. Should sound the same either way. 

But, if you say something like "ground is ground -- they are all the same," you risk being burned at the stake.   :icon_lol:
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: jfrabat on December 10, 2016, 12:03:52 PM
One more question; in the schematics, the pots only use pins 2 & 3 (well, I always assumed "n/c" stood for "not connected; I could be wrong!) but here they are connecting all of them to the PCB.  Should I wire them up?

After further inspection, it looks like Pin 1 of both pots are not going anywhere on the PCB (the square pads).  I'll just leave them disconnected.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: bluebunny on December 10, 2016, 05:30:09 PM
If you're board-mounting your pots, then solder all three connections for a little extra mechanical strength.

If you're connecting via wires, you might in any case want to connect the unused lug on the pot to the middle wiper lug as insurance against the wiper connection going bad.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: jfrabat on December 10, 2016, 06:02:27 PM
The boards are wire mounted.  I will put in the jumper if I get UN-frustrated!  Just finished wiring everything up, put in a fresh PT, and still, no chorus.  Only the dry signal is getting through!  HELP!!!!That's 3 strikes for me already!

Voltages at PT:

Pin #            Freq.Ctrl. V                    Felipe V                     Comment
Pin 1            5V                                 5.01V                        OK
Pin 2            2.38V to 2.42V                2.51V                       A little high; is it an issue?
Pin 3            0V                                 0V                             OK
Pin 4            0V                                 0V                             OK
Pin 5            2.75V                            2.12V                         A little low; is it an issue?
Pin 6            0.61V                            2.43V                         THIS IS AN ISSUE!
Pin 7            0.88V                            0.864V                       OK
Pin 8            0.88V                            0.868V                       OK
Pin 9 to 16   2.41 (slight movement)   2.51V (starts higher)   I think this is OK, right?/td]

Obviously the problem is still coming from PIN 6.  I also still do not get oscillation in PIN 2 (I put the final reading, but it does move when I connect the reader for the first time).

Another thing to note is that PIN 1 on the OpAmp is not oscillating.  The second OpAmp is, though (pins 6-8).  Also, no heat from PT, so that's an improvement.  What do I check now?  The pots?  I am a bit stumped!
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: EBK on December 10, 2016, 06:41:36 PM
You could look at this as great news.  It suggests that your homemade board is probably good if you are having the same problem with the fancy one.

I know you've played around with different chips.   Have you tried replacing any caps?  I assume you recycled these from your other board.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: jfrabat on December 11, 2016, 12:53:41 AM
You could look at this as great news.  It suggests that your homemade board is probably good if you are having the same problem with the fancy one.

I know you've played around with different chips.   Have you tried replacing any caps?  I assume you recycled these from your other board.

Some of them, yeah...  But the store was out of 104 ceramic caps.  Only had 2 left, which is exactly how many I needed to finish the pedal.  I have 104 poly caps, but they are bigger than what fits on the board.  That's why I used the small yellow ones and the 2 ceramic ones (which were not yet in the picture).  I have enough to swap them all out, but stuffing them in will take some creativity...

(http://i46.photobucket.com/albums/f138/jfrabat/Guitar/Pedals/IMG_20161209_222036.jpg) (http://s46.photobucket.com/user/jfrabat/media/Guitar/Pedals/IMG_20161209_222036.jpg.html)

Here you can see the small sized 104 caps I used.  I have 2 ceramic ones in the 2 empty slots above the PT.  The poly ones I have are a little bit bigger than the green 332 that's also above the PT.  The electrolitic caps I can replace with the exception of the 100uF (I think I am out of those).  Should I replace the caps?  Is there a way to test them?

The other thing I have not replaced are the pots.  And the pot quality here is not the best; I already had issues with the pots before.  I may just start with that and see how it goes.  Would bad pots give me this issue?  Is there a way to test them as well?  They are easier to replace than the capacitors...
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: anotherjim on December 11, 2016, 08:23:00 AM
Bad pots would stop the LFO from working. If the speed pot is bad, it won't oscillate. If the depth pot is bad, it won't get through to pin2 of the 2399.

Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: anotherjim on December 11, 2016, 09:10:05 AM
You could be in a position where you cannot have any confidence. Could the PT2399's all be bad? It can happen, depends where you bought them from. It has been known for fakes/rejects to get into the market.
I've found it helpful to set the chip up in a minimal circuit on a breadboard like this...
(http://i.imgur.com/k9On7wE.png)
I forgot values on the in and out caps. These can be 100nF too.
Really only have to connect the signal output to a test amplifier. Simply touching the signal input with, say the tip of a screwdriver, injects noise that comes out obviously time delayed when the delay control is set to maximum resistance. With a continuous test input signal connected, it's hard to tell if there's delay, but turning the delay time control up and down will be heard as pitch shifting.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: jfrabat on December 11, 2016, 11:28:53 AM
You could be in a position where you cannot have any confidence. Could the PT2399's all be bad? It can happen, depends where you bought them from. It has been known for fakes/rejects to get into the market.
I've found it helpful to set the chip up in a minimal circuit on a breadboard like this...
(http://i.imgur.com/k9On7wE.png)
I forgot values on the in and out caps. These can be 100nF too.
Really only have to connect the signal output to a test amplifier. Simply touching the signal input with, say the tip of a screwdriver, injects noise that comes out obviously time delayed when the delay control is set to maximum resistance. With a continuous test input signal connected, it's hard to tell if there's delay, but turning the delay time control up and down will be heard as pitch shifting.

I built the circuit, but I get no sound at all out of it...  2 different PT's.  I'm guessing that's pointing to my problem?
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: EBK on December 11, 2016, 12:09:41 PM
Have we touched upon the possibility of counterfeit PT2399 chips yet?
Title: Re: &quot;Little Angel&quot; - Super Simple PT2399 Mini Chorus
Post by: jfrabat on December 11, 2016, 12:39:41 PM
2 sources both counterfit?

Sent from my EVA-L19 using Tapatalk

Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: anotherjim on December 11, 2016, 05:06:54 PM
Well, underspec/faulty/fake goods get out by the backdoor and sold as legitimate somewhere - to some distributors as well as in small quantities via e-bay, alibaba et al.  I would not expect devices from "knowledgeable" dealers like SmallBear and the bigger traders (Mouser et al) to be suspicious as they likely either chose to, or have to buy from official sources.

If you assume they are first quality goods and should be ok, then you have to ask why aren't they now?

Static damage is the first suspect.

Are you still discharging the chips before use?

Low humidity where you are? This greatly increases the generation of static charge. I seldom have to worry about this -  we've only had 3 low humidity days so far this winter and there's none in the forecast ahead.

Insulated flooring/clothing/work surface? Same effect.

Leaky soldering iron (the tip is not grounded)? Can damage circuits if the chips are in the sockets while soldering.

Incorrect packaging? IC's should either be in an anti-static plastic tube, pressed into anti-static foam or a piece of polystyrene WITH a metal foil surface. If anything came packaged differently - loose in an ordinary bag (anti-static bags ok -  but the pins get bent) or on a plain piece of polystyrene then the supplier is very naughty indeed.


Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: jfrabat on December 11, 2016, 05:09:55 PM
Incorrect packaging? IC's should either be in an anti-static plastic tube, pressed into anti-static foam or a piece of polystyrene WITH a metal foil surface. If anything came packaged differently - loose in an ordinary bag (anti-static bags ok -  but the pins get bent) or on a plain piece of polystyrene then the supplier is very naughty indeed.

The local dealer just gives you the IC.  No packaging.  The ones from amazon came in polysterene, no metal...  So I guess I need to order new ones?
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: anotherjim on December 12, 2016, 06:28:55 AM
In that case, I would definitely suspect those you have and order from another source.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: duck_arse on December 12, 2016, 08:48:51 AM
I've just seen something in another thread, made me think - jfrabat - are you using the same pots as from your first angel build? I don't think we've ever seen them in any photos, is there a chance we might see them, with their wires and solders?

and while I'm grasping at straws, can you put your meter across the pot connection ON THE BOARD (power off, as we are measuring ohms) and turn the pot shaft - does the resistance actually change? what range of reading do you get?
Title: Re: &quot;Little Angel&quot; - Super Simple PT2399 Mini Chorus
Post by: jfrabat on December 12, 2016, 09:18:21 AM
I've just seen something in another thread, made me think - jfrabat - are you using the same pots as from your first angel build? I don't think we've ever seen them in any photos, is there a chance we might see them, with their wires and solders?

and while I'm grasping at straws, can you put your meter across the pot connection ON THE BOARD (power off, as we are measuring ohms) and turn the pot shaft - does the resistance actually change? what range of reading do you get?
Yes, they are the same pots.  I will take some pictures and readings tonight.


Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: jfrabat on December 12, 2016, 07:54:47 PM
500k pot goes from 0.6 ohms to 482K ohms

100k pot goes from 7.0 ohms to 89.8k ohms

I think I got both on backwars, though, as 0 is at full clockwise turn.  Changing them is simplybreplacing pin 1 for pin 3, right?

(http://i46.photobucket.com/albums/f138/jfrabat/Guitar/Pedals/IMG_20161212_185225.jpg) (http://s46.photobucket.com/user/jfrabat/media/Guitar/Pedals/IMG_20161212_185225.jpg.html)
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: duck_arse on December 13, 2016, 08:23:35 AM
IF those pot resistance measures are at the board, then the pot wires and the pots are ok. and yes, swap 1 for 3 if they work backwards [but log (A /audio taper) pots will feel odd, bunched one end when reversed].

and now your pots - those rivet/eyelets holding the solder tag against the carbon track/pot wafer are not for our use! don't be poking wires and solder thru them, cause if they expand or loosen or wiggle, the pot is shot. (or that connection is shot, anyway.) and poor solder connections that close to the pot body cause many a crying builder. so wrap the wire around the lug/pin and solder, or cut a very small piece of vero or perf, solder that to the pins, and then wires into the board.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: EBK on December 13, 2016, 08:30:30 AM
To add to what Stephen said: In the future, do not solder pots that way, but don't unsolder these now or you run the risk of destroying them.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: jfrabat on December 13, 2016, 10:07:12 AM
I took the readings at the pots themselves; I will retake the readings tonight (or tomorrow night, as I have a business dinner tonight) at the board to be sure.  As for the rivet, I think I now understand why I damaged so many pedals on my last build...  I just thought they were poor quality!  Live and learn, I guess... 
Title: Re: &quot;Little Angel&quot; - Super Simple PT2399 Mini Chorus
Post by: jfrabat on December 18, 2016, 03:05:26 AM
New PT's on the way (Smallbear).  It should take some time for them to get here, though, considering the season and the i ternational shipping.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: jfrabat on January 04, 2017, 08:47:09 PM
Well, guys, I am officially stomped!  New PT's arrived, but no change in behavior from the pedal!  AAAARRRHHHGGG!!! >:( >:( >:(
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: EBK on January 04, 2017, 09:00:45 PM
I understand your frustration.  :icon_sad: Could you post some updated pics, including all the off-board wiring?  On the (somewhat) bright side, the fact that new PTs didn't change anything does narrow our focus a bit.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: jfrabat on January 05, 2017, 10:29:19 AM
I'll trouble shoot it (AGAIN!) tonight, and take some new pictures.  I plan to:

1. Verify that all resistors and capacitors values are what they should be
2. That all IC's are connected the right way (yeah, I have done that before!)
3. Will most likely replace the pots (I got some new better ones from Small Bear and Mammoth to replace the cheap ones I have been using; but this I am leaving for last, as the ones I got were working last time I checked)

Anything else I should look for?
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: jfrabat on January 05, 2017, 08:37:12 PM
OK, this is what I have so far:

I bought this  (http://jmkpcbs.com/product/little-angel/)pcb from jmkpcbs.com

Here's the build instructions:

(http://i46.photobucket.com/albums/f138/jfrabat/Guitar/Pedals/Build.jpg) (http://s46.photobucket.com/user/jfrabat/media/Guitar/Pedals/Build.jpg.html)

And this is how mine is looking as of today:

(http://i46.photobucket.com/albums/f138/jfrabat/Guitar/Pedals/20170105_183705.jpg) (http://s46.photobucket.com/user/jfrabat/media/Guitar/Pedals/20170105_183705.jpg.html)

(http://i46.photobucket.com/albums/f138/jfrabat/Guitar/Pedals/20170105_183758.jpg) (http://s46.photobucket.com/user/jfrabat/media/Guitar/Pedals/20170105_183758.jpg.html)

And the pots:

(http://i46.photobucket.com/albums/f138/jfrabat/Guitar/Pedals/20170105_183638.jpg) (http://s46.photobucket.com/user/jfrabat/media/Guitar/Pedals/20170105_183638.jpg.html)

Changes from the plan are basically replacing the TL072 for a TL082.

Voltages are:

PT2399:
Pin 1      5.03V
Pin 2      2.51V
Pin 3      0V
Pin 4      0V
Pin 5      2.93V
Pin 6      2.42V
Pin 7      0.683V
Pin 8      0.696V
Pin 9 through 16    2.51V (Some movement when you first connected)

TL082
Pin 1      4.55V
Pin 2      4.55V
Pin 3      4.41V
Pin 4      0V
Pin 5      2.86 to 2.94V
Pin 6      3.00 to 3.04V
Pin 7      2.75 to 3.30V
Pin 8      9.04V

78L05
Vin      9.03V
Gnd     0V
Vout    5.03V

2N3904
C          2.42V
B          0.447V
E          0V

I will use the photo above to go through the resistance values to make sure I did not use the wrong ones.  I will also check the caps, but later on, as I have to do some stuff now...  For everyone's reference, this is also stated in the instructions:

L is the + connection of the LED
I is PCB Input
G is the ground for the switch (mine is soldered to the jack)
O is the PCB Output
+ is 9V in
- is ground for DC jack
GND is extra ground for 1/4" jack
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: EBK on January 06, 2017, 11:14:28 AM
Could you post a pic of the jacks (I/O and DC) and stomp switch?
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: stallik on January 06, 2017, 11:34:56 AM
phone's too small to look it up but will the replacement of the TL072 with at the TL082 make any odds?
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: EBK on January 06, 2017, 11:36:59 AM
phone's too small to look it up but will the replacement of the TL072 with at the TL082 make any odds?
It's compatible, but has better noise performance than the TL072, if I recall correctly.  Shouldn't cause any problems here.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: jfrabat on January 06, 2017, 01:06:27 PM
Could you post a pic of the jacks (I/O and DC) and stomp switch?

Sure, I will post them tonight.  But I am pretty sure the problem is not there, because I get the bypass signal just fine and when I activate the effect, the dry signal goes through (if I lift the resistor, the dry signal goes away).  I will post them anyway, though, just in case.

phone's too small to look it up but will the replacement of the TL072 with at the TL082 make any odds?
It's compatible, but has better noise performance than the TL072, if I recall correctly.  Shouldn't cause any problems here.

I think I have some Tl072 in the OpAmp kit I bought; I could change them and see what happens...
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: EBK on January 06, 2017, 01:31:42 PM
Could you post a pic of the jacks (I/O and DC) and stomp switch?

Sure, I will post them tonight.  But I am pretty sure the problem is not there, because I get the bypass signal just fine and when I activate the effect, the dry signal goes through (if I lift the resistor, the dry signal goes away).  I will post them anyway, though, just in case.
I understand what you are saying.  The thing that prompts me to ask is that, from my understanding, you are having the same or similar problems despite swapping out whole boards and tons of parts. 

Occasionally, "pretty sure the problem is not there," is the reason we don't find the problem.  :icon_wink:
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: jfrabat on January 06, 2017, 08:43:16 PM
Occasionally, "pretty sure the problem is not there," is the reason we don't find the problem.  :icon_wink:

Good point!

Here are the other pictures.  Mind you, there is no DC jack (yet).

(http://i46.photobucket.com/albums/f138/jfrabat/Guitar/Pedals/20170106_193716.jpg) (http://s46.photobucket.com/user/jfrabat/media/Guitar/Pedals/20170106_193716.jpg.html)

(http://i46.photobucket.com/albums/f138/jfrabat/Guitar/Pedals/20170106_193800.jpg) (http://s46.photobucket.com/user/jfrabat/media/Guitar/Pedals/20170106_193800.jpg.html)

(http://i46.photobucket.com/albums/f138/jfrabat/Guitar/Pedals/20170106_193821.jpg) (http://s46.photobucket.com/user/jfrabat/media/Guitar/Pedals/20170106_193821.jpg.html)

Felipe
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: jfrabat on January 06, 2017, 09:02:52 PM
OK, I was checking my resistors; found one inconsistency (I think; can you please verify?):

R1: 100K (OK)
R2: 4.1K (NOT REALLY USED)
R3: 10K (OK)
R4: 10K (OK)
R5: 10K (OK)
R6: 10K (OK)
R7: 33K (OK)
R8: 68K (OK)
R9: 10K (OK)
R10: 10K (OK)
R11: 10K (OK)
R12: 100 (OK)
R13: 2.2K (OK)
R14: 220K (OK)
R15: 4.1K (SHOULD BE 4.7k; AM I READING THIS RIGHT?  COULD THIS BE THE CAUSE?)
R16: 220K (OK)
R17: 100K (OK)
R18: 47K (OK)
R19: 10K (OK)
R20: 10K (OK)
R21: 1M (OK)
R22: 330K (OK)
R13: 10K (OK)
R14: 470K (OK)
R15: 1M (OK)

Can you guys confirm if R15 is really wrong?  Could it be the cause of my problems?
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: bluebunny on January 07, 2017, 06:35:21 AM
Are these two "4.1K"s measured (out of circuit) or eyeballed?  (FYI, 4.1K isn't a value in E12, nor yet in E24.)  Either way, they shouldn't make any noticeable difference.
Title: Re: &quot;Little Angel&quot; - Super Simple PT2399 Mini Chorus
Post by: jfrabat on January 07, 2017, 08:40:40 AM
I checked the bands, not the measurements....
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: bluebunny on January 07, 2017, 10:29:48 AM
Then they're 4.7K.
Title: Re: &quot;Little Angel&quot; - Super Simple PT2399 Mini Chorus
Post by: jfrabat on January 07, 2017, 07:04:03 PM
Is it worth it redoing everything off board?  New pots and jacks and switch?  I got enough to do it...
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: bluebunny on January 08, 2017, 06:38:24 AM
What's connected to the stereo output jack?  If you're using it to switch on the power, then I'd expect to see the black lead from the battery connected to the ring lug (and to nowhere else).  It's a bit difficult to see what's going on.  Perhaps you could take a picture where we see everything: board, pots, jacks, switch?
Title: Re: &quot;Little Angel&quot; - Super Simple PT2399 Mini Chorus
Post by: jfrabat on January 08, 2017, 06:57:39 AM
I think I am going to redo everything today.  I have a better quality  wire, pots and stereo jack now, so might as well get the good ones in to match the awesome board I got.  So even if the error is not there, there will be better quality compone ts used.
Title: Re: &quot;Little Angel&quot; - Super Simple PT2399 Mini Chorus
Post by: jfrabat on January 08, 2017, 09:36:00 AM
Here are the pics...

(http://i46.photobucket.com/albums/f138/jfrabat/Guitar/Pedals/20170108_082851.jpg) (http://s46.photobucket.com/user/jfrabat/media/Guitar/Pedals/20170108_082851.jpg.html)

(http://i46.photobucket.com/albums/f138/jfrabat/Guitar/Pedals/20170108_082922.jpg) (http://s46.photobucket.com/user/jfrabat/media/Guitar/Pedals/20170108_082922.jpg.html)

(http://i46.photobucket.com/albums/f138/jfrabat/Guitar/Pedals/20170108_082928.jpg) (http://s46.photobucket.com/user/jfrabat/media/Guitar/Pedals/20170108_082928.jpg.html)

(http://i46.photobucket.com/albums/f138/jfrabat/Guitar/Pedals/20170108_082941.jpg) (http://s46.photobucket.com/user/jfrabat/media/Guitar/Pedals/20170108_082941.jpg.html)

(http://i46.photobucket.com/albums/f138/jfrabat/Guitar/Pedals/20170108_083008.jpg) (http://s46.photobucket.com/user/jfrabat/media/Guitar/Pedals/20170108_083008.jpg.html)

Title: Re: &quot;Little Angel&quot; - Super Simple PT2399 Mini Chorus
Post by: jfrabat on January 08, 2017, 09:36:58 AM
By the way, I noticed I am out of 500K pots...  So no can do on the remake (I could rewire, though).
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: jfrabat on January 10, 2017, 11:16:55 AM
Bump...  Any ideas?  I am flat out...
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: maiko on January 11, 2017, 12:44:15 AM
Ive been following on this for a long time and am sorry you havent gotten
this to work. 

But . . . for me most of the cases were solve by simple obvious things. 

You probably already have  ..  . but i would ask again are you sure your in and out
is not backward.   i mean maybe your plugging your guitar and amp on the wrong ends
have you tried this?

Also i notice you solder your pots on the base.  Ive tried this and everytime
the pot is damaged thats why i wont solder there anymore.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: jfrabat on January 11, 2017, 10:22:26 AM
i would ask again are you sure your in and out
is not backward.   i mean maybe your plugging your guitar and amp on the wrong ends
have you tried this?

Yup.  I double checked, and I am connecting the right way in.  Notice that I use different type of connectors, so it is easy to tell them apart...

Also i notice you solder your pots on the base.  Ive tried this and everytime
the pot is damaged thats why i wont solder there anymore.

I checked the pots a few replies back, and they were both OK.  I was planning on changing them, but I am out of 500K pots...  I may just change the 100K one, though, as I still got some of those (don't remember if I got them in B or C, though).
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Perrow on January 13, 2017, 10:36:02 AM
Are you sure you've used the right pads for the pots?
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: jfrabat on January 13, 2017, 03:15:26 PM
Orange and Green are in the middle position, so yeah...  If the white wire was on backwards, the pods would be backwards, but it would work...
Title: Re: &quot;Little Angel&quot; - Super Simple PT2399 Mini Chorus
Post by: jfrabat on January 18, 2017, 04:27:09 PM
I decided to put new pots in, and try without a stomp switch (wiring the board directly to the jacks) and see how it goes.  I took everything off the board last night, and will start soldering everything together tonight.  Keeping my fingers crossed!
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: maiko on January 18, 2017, 09:11:46 PM

I was just about to suggest taking the switch out just direct in and out
Title: Re: &quot;Little Angel&quot; - Super Simple PT2399 Mini Chorus
Post by: jfrabat on January 18, 2017, 10:32:54 PM
Decided on a movie night with the wife instead, so no progress today!
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: jfrabat on January 22, 2017, 10:56:34 PM
OK, tried bypassing the stomp switch.  Used new pots also.  No change.  Same issue; the dry signal gets through, but the wet signal is nowhere to be found.  Used new PT (a fresh one I got from Smallbear), new TL072 (replacing the TL082 I had in, just to be sure that was not the issue), but we have no change whatsoever.  Here are the pics of how it stands (notice that the OpAmp changes in one of them).  If you can spot anything going on, please pointed out to me. 

This is getting VERY frustrating!  out of the 5 pedals I have worked on, one works flawlesly, one works, but I do not like the sound, this one dows not work, the EA Tremolo does not work, and the Vulcan Rat worked, but then something happened and it stopped working (I have yet to dive into that one to figure out why; I am sure it is something as simple as a broken wire).  I cant be THAT much of a crappy DIYer!

(http://i46.photobucket.com/albums/f138/jfrabat/Guitar/Pedals/20170122_214335.jpg) (http://s46.photobucket.com/user/jfrabat/media/Guitar/Pedals/20170122_214335.jpg.html)

(http://i46.photobucket.com/albums/f138/jfrabat/Guitar/Pedals/20170122_214158.jpg) (http://s46.photobucket.com/user/jfrabat/media/Guitar/Pedals/20170122_214158.jpg.html)

(http://i46.photobucket.com/albums/f138/jfrabat/Guitar/Pedals/20170122_214140.jpg) (http://s46.photobucket.com/user/jfrabat/media/Guitar/Pedals/20170122_214140.jpg.html)

(http://i46.photobucket.com/albums/f138/jfrabat/Guitar/Pedals/20170122_214103.jpg) (http://s46.photobucket.com/user/jfrabat/media/Guitar/Pedals/20170122_214103.jpg.html)

(http://i46.photobucket.com/albums/f138/jfrabat/Guitar/Pedals/20170122_214049.jpg) (http://s46.photobucket.com/user/jfrabat/media/Guitar/Pedals/20170122_214049.jpg.html)

(http://i46.photobucket.com/albums/f138/jfrabat/Guitar/Pedals/20170122_214041.jpg) (http://s46.photobucket.com/user/jfrabat/media/Guitar/Pedals/20170122_214041.jpg.html)

(http://i46.photobucket.com/albums/f138/jfrabat/Guitar/Pedals/20170122_214017.jpg) (http://s46.photobucket.com/user/jfrabat/media/Guitar/Pedals/20170122_214017.jpg.html)

Could it be the ceramic caps?  I read somewhere that they are not that great...  What else could it be?  Voltages are the same as last time I posted them:

PT2399:
Pin 1      5.03V
Pin 2      2.51V
Pin 3      0V
Pin 4      0V
Pin 5      2.93V
Pin 6      2.42V
Pin 7      0.683V
Pin 8      0.696V
Pin 9 through 16    2.51V (Some movement when you first connected)

TL082
Pin 1      4.55V
Pin 2      4.55V
Pin 3      4.41V
Pin 4      0V
Pin 5      2.86 to 2.94V
Pin 6      3.00 to 3.04V
Pin 7      2.75 to 3.30V
Pin 8      9.04V

78L05
Vin      9.03V
Gnd     0V
Vout    5.03V

2N3904
C          2.42V
B          0.447V
E          0V

Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: EBK on January 23, 2017, 12:02:06 AM
Felipe,
I really hate to see your bad luck continue with this pedal, especially since your soldering appears to have improved so much since you started this project.

I haven't brushed up on the PT2399 lately, and I don't know for sure what every voltage is supposed to be, but I suspect you have a collection of perfectly fine chips and the problem lies elsewhere (of course, I've warned you before about "problem lies elsewhere" thinking, and I'm not heeding my own advice at the moment  :icon_rolleyes:). 

One thing that caught my eye, and I'm not sure if it makes a difference, is your diode D1.  The spec calls for 1N4148.  Yours looks different from the 4148s I've encountered before....  I'm wondering if just maybe (this is a longshot) you have the wrong sort of diode and that is messing up things with Q1 and pin 6 of the 2399.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: jfrabat on January 23, 2017, 12:46:47 AM
EBK, thanks for your patience with me, and for the complement of my improving skills!

I am not a huge connoisseur in electronics, but the diode DOES say 41 and then 48 right below it...  My guess is that it is a 4148 (I am assuming the 1N part; it is not written in the diode; there is something, but I cant figure it out), but I am not 100% sure on that.  Here are the pics (by the way, the numbers are TINY!  I had a real hard time checking!  And I was using one that was not installed!).

(http://i46.photobucket.com/albums/f138/jfrabat/Guitar/Pedals/20170122_234157.jpg) (http://s46.photobucket.com/user/jfrabat/media/Guitar/Pedals/20170122_234157.jpg.html)

(http://i46.photobucket.com/albums/f138/jfrabat/Guitar/Pedals/20170122_234209.jpg) (http://s46.photobucket.com/user/jfrabat/media/Guitar/Pedals/20170122_234209.jpg.html)

Here's the symbol (whatever it is) that's above the 41 (looks like a script T or something):

(http://i46.photobucket.com/albums/f138/jfrabat/Guitar/Pedals/20170122_234850.jpg) (http://s46.photobucket.com/user/jfrabat/media/Guitar/Pedals/20170122_234850.jpg.html)

I looked up 1N4148 in Google (images) and found many similar to mine, though, so I am now even more sure that this SHOULD be the right one...

Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: EBK on January 23, 2017, 06:34:20 AM
Got it.  Thought your installed one looked darker and had a 0 on it.  Must have just been the lighting.  Oh well. 
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: duck_arse on January 23, 2017, 08:28:40 AM
so, what parts are common to this build and the previous?
Title: Re: &quot;Little Angel&quot; - Super Simple PT2399 Mini Chorus
Post by: jfrabat on January 23, 2017, 09:11:49 AM
There is a 4007 on, but thats D2...
Title: Re: &quot;Little Angel&quot; - Super Simple PT2399 Mini Chorus
Post by: EBK on January 23, 2017, 09:18:36 AM
There is a 4007 on, but thats D2...
I was just seeing the bottom of the 8 on D1 as a 0.  I can actually make out the "48" now that I've taken another look.  You've got the right part.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: EBK on January 23, 2017, 09:30:28 AM
I apologize for not taking the time to go back and reread everything you've done so far, but have you tried the following with an audio probe?

1.  Check to see if your dry signal is making it to the 2399 input.
2.  Check to see if you are getting a signal out of the 2399 output.
Title: Re: &quot;Little Angel&quot; - Super Simple PT2399 Mini Chorus
Post by: jfrabat on January 23, 2017, 09:53:49 AM
I did, but a while ago.  I'll try it again and see what happens.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: jfrabat on January 25, 2017, 04:50:28 PM
so, what parts are common to this build and the previous?

Most of them.  Is it time to take them all out and replace them?
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: duck_arse on January 26, 2017, 08:14:09 AM
no. list them, we'll see what we can pick from the list. if you keep getting the same problem with each rebuild using the same parts, logic says it's one of those parts.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: EBK on January 26, 2017, 08:55:35 AM
no. list them, we'll see what we can pick from the list. if you keep getting the same problem with each rebuild using the same parts, logic says it's one of those parts.
+1
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: jfrabat on January 26, 2017, 11:13:53 AM
You know what, when I ordered the PCB from JMK, I did not receive the PCB in a long while, so they sent me a new one.  Well, it turns out that yesterday the original one arrived.  So one option would be to use the new PCB and start from scratch.  That way I know I am not using the same components as the previous versions! 

By the way, and for the record, I already notified them that I received it yesterday, and Jacob told me to just keep the PCB.  What a great service from these guys!  I truly recommend them, not only because their PCB ROCK (see the picture below), but their service is impecable.

(http://i46.photobucket.com/albums/f138/jfrabat/Guitar/Pedals/IMG_20161208_223222.jpg)

I think I have enough stock to make a new one without having to reuse components.  Now, quick question, though; should I use ceramic disc capacitors again?  Or should I try to find Poly film ones instead? 
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: maiko on January 26, 2017, 07:43:30 PM
Watching this and rooting for you.  I hope you get a working chorus pedal soon. :)
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: EBK on January 27, 2017, 12:42:14 AM
Quote
Now, quick question, though; should I use ceramic disc capacitors again?  Or should I try to find Poly film ones instead?
I would suggest finding film caps, but not necessarily for the reason you might think.  You are about to build this thing for the third(?) time.  Anything that slows you down may also help prevent your muscle memory and/or subconscious secretly repeating a mistake we haven't spotted. 

Sounds weird, but I have to imagine there are dozens of us here (with a nod to maiko chiming in with something remarkably similar to something I too posted way back) that need you to succeed with this project, if for nothing else, to reaffirm that patient persistence and a positive attitude pays off (if you quit, we will all patiently and persistently hold you down and positively force you to keep building this thing -- just kidding  :icon_razz:).
Title: Re: &quot;Little Angel&quot; - Super Simple PT2399 Mini Chorus
Post by: jfrabat on January 27, 2017, 01:04:36 AM
I will try to find poly film ones then.  Not sure how easy they are to find in Costa rica, but I will try.  By the way, it is the FOURTH try!  Now, I am nlt sure what's the right adjective for me...  My wife would  probably not call me so much as persistent than hard headed, but one thing is for sure; I tend not to give up (failling pisses me off, and I cant shake that feeling until I succeed, so I keep doing thing until they come out right). 

I will most likely finish my Vulcan Rat first, though.  I had that one working, and the crappi cables I was using kept breaking, so I will do that one again.  I just finished drilling the holes in the PCB I made for that one a few minutes ago (and its the best PCB I have made so far, if I do say so myself!).  But this Little Angel battle is far from over!  I will report back soon!  And thanks to all for the words of support and the technical help!  You guys ROCK!
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: jfrabat on February 12, 2017, 04:06:38 PM
You could be in a position where you cannot have any confidence. Could the PT2399's all be bad? It can happen, depends where you bought them from. It has been known for fakes/rejects to get into the market.
I've found it helpful to set the chip up in a minimal circuit on a breadboard like this...
(http://i.imgur.com/k9On7wE.png)
I forgot values on the in and out caps. These can be 100nF too.
Really only have to connect the signal output to a test amplifier. Simply touching the signal input with, say the tip of a screwdriver, injects noise that comes out obviously time delayed when the delay control is set to maximum resistance. With a continuous test input signal connected, it's hard to tell if there's delay, but turning the delay time control up and down will be heard as pitch shifting.

OK, guys, I revisited the testing circuit.  Remade the whole thing on the breadboard.  When the pot is at 0, sound comes out, but if I turn it up, A LOT of noise comes out and no delay effect.  I am about ready to start construction of the new board (now that I have the EA Tremolo and Vulcan Rat pedals all done, so this one is the only one on the building table as of now; of course, with a board for a phaser, that can rapidly change).  But I am really looking forward to building a Chorus and a Delay (which I think are musts), and the Chorus is the one that has so far beaten me (but that will NOT be the end result!). 

Anyway, back to the testing circuit, I tried replacing the PT and the Pot, but the result is still the same.  I want to be sure the PT I use on the new board is sound, so I want to attack this problem first.  Any ideas?  By the way, the circuit is exactly as above, with the exception of the Pot being 50K instead of 47K.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: EBK on February 12, 2017, 04:13:45 PM
I was happy to see you get other stuff to work.  Now we can lay to rest the theory that your soldering iron shoots lightning bolts through whatever it touches.   :icon_wink:

How many PT2399s do you have?
Did you find new caps?

Title: Re: &quot;Little Angel&quot; - Super Simple PT2399 Mini Chorus
Post by: jfrabat on February 12, 2017, 04:14:59 PM
I have about 10 from 3 sources (including Small Bear).  I have not yet looked for the caps, though.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: EBK on February 12, 2017, 04:17:49 PM
Are you at least using new (non-recycled) caps for this?
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: jfrabat on February 12, 2017, 06:11:41 PM
Are you at least using new (non-recycled) caps for this?

Yes and no, the old pedal is still built, but these are the same caps I had on the breadboard before.  I have enough to replace them, but I figured what are the odds of these caps and the ones in the pedal being all bad, right?.  I will not take it apart so as not to reuse any part.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: jfrabat on March 03, 2017, 11:39:59 PM
OK, finally started the new Little Angel board.  Basically got everything in the board except for the 4.7K resistor (CLR), a 100uF cap (need to buy some), and the 2N3904.  When I got to the last component, I started looking in my parts to find it, but I noticed I did not have any.  Checked the old board, and noticed I have a 2N2222 in there.  Looked at my previous post, and I did mention it before, but there were no comments on it.  My question is, are they interchangeable?  It seems the only difference is the current they can handle (with the 2222 having more capacity)...  Is this right?
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: EBK on March 04, 2017, 06:59:41 AM
Correct.  2n2222 can handle more current.  Should be fine.  (And now, we know that you have working delay chips!)
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: jfrabat on March 04, 2017, 01:21:25 PM
(And now, we know that you have working delay chips!)

Right!  I am keeping the breadboard (I plan to build the Deep Blue Delay as a pedal, but will not use the components on the breadboard) so that if I suspect PT2399 lockup, I can use that to test it.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: EBK on March 04, 2017, 01:30:24 PM
(And now, we know that you have working delay chips!)

Right!  I am keeping the breadboard (I plan to build the Deep Blue Delay as a pedal, but will not use the components on the breadboard) so that if I suspect PT2399 lockup, I can use that to test it.
Good plan!
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: jfrabat on March 04, 2017, 07:46:41 PM
This is where I am at now...

(http://i46.photobucket.com/albums/f138/jfrabat/Guitar/Pedals/20170304_183955.jpg)

As you can see, I got a 470K resistor missing.  Checking my work, I noticed I had put a 470R in by mistake.  Since I was all out of 470K, I went to the store, and guess what?  They gave me 470R by mistake and I did not notice until I got home!!!  Argh!!!  Will have to get resistors on Monday now.

Anyway, I ditched the ceramic capacitors and used box capacitors instead.  All components are new, no carry over from the previous pedals...  The store was also out to 100uF caps, so I need to get that as well.

By the way, I am out of C500K pots; should I use A500K instead?  C is not really all that common in Costa Rica (I have B and A, but the A is Alpha and the B is a cheapo Chinese pot)
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: jfrabat on March 12, 2017, 12:35:39 PM
Here are voltages just taken from my Little Angel, which sounds the same as the breadboarded version I did you soundclips on. Speed at 3 o'clock, Depth at 12 o'clock:

PT2399

1:  5
2:  2.38 to 2.42
3:  0
4:  0
5:  2.75
6:  0.61
7:  0.88
8:  0.88
9 through to 16:  2.41 (slight movement)


NE5532

1:  0.13 to 4.9
2:  2.9 to 3.2
3:  2.7 to 3.1
4:  0v
5:  4.79
6.  4.9
7:  5.14
8:  9

OK, guys.  I am officially STUMPED and PO'ed!  This is the THIRD time I build this pedal, this time with ALL new parts (no recycled ones from previous tries), and I have EXACTLY the same result.  First time I tried etching my board.  Second and third I used boards from JMK PCB.  WHAT AM I DOING WRONG???

Here are my voltages:

Battery: 9.20V

TL082:
1: 4.68V
2: 4.68
3: 4.53V
4: 0V
5: 2.80 to 3.70V
6: 2.88 to 3.65V
7: 0 to 1.4V
8: 9.20V

78L05:
IN: 9.2V
GND: 0V
OUT: 5.01V

2N2222:
C: 0V
B: 0.449V
E: 2.43V

PT2399:
1: 5.01V
2: 2.5V
3: 0V
4: 0V
5: 3.40V (should be around 2.65V)
6: 2.43V (should be 0.61V)
7: 0.875V
8: 0.995V
9 to 16: around 2.5V with movements

PT2399 was tried out in the Deep Blue Delay BB, so it is working.  All caps and resistors were double checked, and they are correct (same with the previous board, which is still built).  here are some pics so that you can check if you see something I do not (and yes, the battery WAS plugged in when I tried it):

(http://i46.photobucket.com/albums/f138/jfrabat/Guitar/Pedals/20170312_101957.jpg)

(http://i46.photobucket.com/albums/f138/jfrabat/Guitar/Pedals/20170312_102122.jpg) (http://s46.photobucket.com/user/jfrabat/media/Guitar/Pedals/20170312_102122.jpg.html)

(http://i46.photobucket.com/albums/f138/jfrabat/Guitar/Pedals/20170312_102106.jpg)

(http://i46.photobucket.com/albums/f138/jfrabat/Guitar/Pedals/20170312_102056.jpg)

(http://i46.photobucket.com/albums/f138/jfrabat/Guitar/Pedals/20170312_102042.jpg)

Any other ideas?  I cant believe I can build all other boards and not get this one to work!
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: EBK on March 12, 2017, 01:04:18 PM
Thought this was the fourth build.
Anyway, it is quite a mystery.  I did laugh as I instinctively looked at the soldering first, but in a good way.  I remembered where you started.  Soldering looks very good now (I've told you this before).  Your wiring is looking good too, but what is that black wire hanging out by itself and only connected at one end?
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: jfrabat on March 12, 2017, 02:25:01 PM
what is that black wire hanging out by itself and only connected at one end?

I miscounted the grounds.  It is just an extra ground.  I will de-solder it (most likely, I will replace the ground on top and replace it with this one)
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: jfrabat on March 12, 2017, 02:31:16 PM
Thought this was the fourth build.

Actually, you are right!

BUILD 1
(http://i46.photobucket.com/albums/f138/jfrabat/Guitar/Pedals/20161122_193134_2.jpg)

BUILD 2
(http://i46.photobucket.com/albums/f138/jfrabat/Guitar/Pedals/20161203_212547.jpg)

BUILD 3
(http://i46.photobucket.com/albums/f138/jfrabat/Guitar/Pedals/20170105_183758.jpg)

BULD 4
(http://i46.photobucket.com/albums/f138/jfrabat/Guitar/Pedals/20170312_102122.jpg)

I guess I have improved...  Practice makes perfect, right?   ;D

Now if I could only get this darn thing to WORK!  What I cant understand is why i can get all the other pedals (Vulcan Rat, Deep Blue Delay, Screechy Cat, EA Tremolo, etc.) to work, but not this one (even after 4 tries!)...
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: anotherjim on March 12, 2017, 02:32:22 PM
2N2222:
C: 0V
B: 0.449V
E: 2.43V

These can't be right. E (Emitter) should be directly connected to 0v. Is board meant for 2N3904? Your 2N2222 may not be same pin order.

Anyway, I suggest you take this transistor out and see what it does then.

Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: EBK on March 12, 2017, 02:48:04 PM
what is that black wire hanging out by itself and only connected at one end?

I miscounted the grounds.  It is just an extra ground.  I will de-solder it (most likely, I will replace the ground on top and replace it with this one)
What if you didn't miscount?
Perhaps try grounding that wire. 
When I have more time, I'll take another look at those voltages....
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: jfrabat on March 12, 2017, 04:48:04 PM
What if you didn't miscount?
Perhaps try grounding that wire. 
When I have more time, I'll take another look at those voltages....

Just tried it in case that was the issue...  No change.

2N2222:
C: 0V
B: 0.449V
E: 2.43V

These can't be right. E (Emitter) should be directly connected to 0v. Is board meant for 2N3904? Your 2N2222 may not be same pin order.

Anyway, I suggest you take this transistor out and see what it does then.



You are right: I mislabeled the ports.  E is 0V and C is 2.43V.  Base is correct at 0.049V.  Anyway, I double checked the pinouts of both, and theydo match:

(https://encrypted-tbn2.gstatic.com/images?q=tbn:ANd9GcTFHu9uua-41L34ScZCG1AgjSDsWkcbz5lVaEDyJE9iy1PcSfzf)

(http://lampatronics.com/wp-content/uploads/2015/04/2n2222.jpg)

I also used this (http://www.learningaboutelectronics.com/Articles/2N3904-vs-2N2222.php) information before making the swap. 
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: maiko on March 12, 2017, 09:08:48 PM
3904 2n2222 2n5088 2n5089 all the same pin out i use interchangeably No problems
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: jfrabat on March 12, 2017, 10:26:12 PM
Whatever is going on, I am pretty sure once I fix it, I will have 2 chorus...  Since the other one was doing exactly the same thing, they probably have the same issue.  By the way, I did not have and 500C pot, so I used a 500A wired backwards.  Not optimal, but it SHOULD work, right?
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: maiko on March 13, 2017, 03:30:25 AM
i got mine to work with "b" pots or linear taper
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: stallik on March 13, 2017, 01:42:34 PM
so I used a 500A wired backwards.  Not optimal, but it SHOULD work, right?

Err. if you wired it backwards, then it's probably working in reverse. ie when you think it's full on, its actually full off if that makes sense. I'd hate to think the pedal is working OK but you have the effect level at minimum..... sure you tried that but thought I'd mention it
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: anotherjim on March 13, 2017, 02:58:01 PM
I have to say that I really don't like the control current transistor arrangement. On power off, the 47uF timing capacitor is expected to discharge into the 5v rail via the reverse diode - however this diode could be 0.8Vf while we see the transistor BE is only 0.5Vf, so that diode is not really doing anything. I believe it is possible to power the chip up and down with the transistor always on so the chip has to start with 100R which we know is bad.
I repeat advice to take the transistor or 100R out!
Title: Re: &quot;Little Angel&quot; - Super Simple PT2399 Mini Chorus
Post by: jfrabat on March 13, 2017, 03:13:53 PM
OK, i did not get anything except try without the 100R resistor.  Is that correct?
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: anotherjim on March 13, 2017, 06:18:29 PM
Yes, the 100R, because that is a major difference between this circuit and the delays that work.

Title: Re: &quot;Little Angel&quot; - Super Simple PT2399 Mini Chorus
Post by: jfrabat on March 13, 2017, 06:48:43 PM
Do I replace it, jumper it or just leave the conection open?
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: anotherjim on March 14, 2017, 05:35:59 AM
Remove it.
Title: Re: &quot;Little Angel&quot; - Super Simple PT2399 Mini Chorus
Post by: jfrabat on March 14, 2017, 09:19:00 AM
Ok.  I will try it.  So if I am reading the diagram right, that would take the transistor out of the equation, right?  OK, I will try. 

Now, quick question, to make this a richer learning experience; explain to a noob in simple words what is the purpose of that transistor (to understand why I am taking out of the loop).  In my overdrive, I use them for boost (or so I understood, anyway!), but this pedal uses an OpAmp, so it should not be the source of boost, right?
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: EBK on March 14, 2017, 09:25:35 AM
It's being used as a delayed switch here, I believe.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: anotherjim on March 14, 2017, 11:17:30 AM
Yes it's time delay switch using the transistor as the "switch"

On power up the 100R should be disconnected from the PT2399. The transistor should be turned off initially and that means there is no path to 0v through the transistor collector-emitter for the 100R, effectively switching it out of circuit. When the 47uF capacitor charges up sufficiently (the time delay), the transistor turns on because there is enough voltage to "forward bias" it's base-emitter junction. In your case, this appears to happen about 0.5V.
(http://s11.postimage.org/f4n92ssj7/Modded_Angel.png)
This was the easiest schematic to find -  ignore the red modification notes.

Now, the time delay is how long it takes the 47uF to charge via the 68k resistor. This must be long enough for the PT2399 internals to get running normally with only the 2k2 resistor setting the delay time. Then the 100R can be switched in, making the PT2399 delay shorter to suit the chorus effect.

If you think about it, the time delay due to the 47uF capacitor only happens IF the capacitor is completely discharged before power is switched on. I'm not sure that this is always happening. Indeed the 47uF may keep a small charge for a very long time after 9v power is removed.

A cure might be to fit another 1N4148 diode in series with the transistor base. This would raise the time it takes for the capacitor charge to turn the transistor on AND negate the effect of any small charge remaining in the capacitor from the last time power was applied. I also wonder if it wouldn't be better for the existing 1N4148 diode that is meant to discharge the capacitor to have it's cathode connected to the 9v supply instead of 5v. I suspect it will be able to discharge the capacitor faster that way.

This is a bit technical, but MOS devices like the PT2399 tend to have very high resistance to the power supply once the supply voltage falls to about 1v, because none of the MOS transistors in it can be turned on at that low a voltage, so there isn't much resistive loading on the 5v supply that could discharge the 47uF capacitor below that 0.5v level. It could perhaps have 0.4v on it for quite some time.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: jfrabat on March 14, 2017, 12:12:56 PM
You know, now that you mentioned the transistor, it got me wondering; I know that transistors can get damaged by heat when soldering.  I did not socket my transistors.  Could it be that I damaged them while soldering?  Should I try removing the transistor and soldering a socket and THEN trying the pedal?
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: EBK on March 14, 2017, 12:14:26 PM
You know, now that you mentioned the transistor, it got me wondering; I know that transistors can get damaged by heat when soldering.  I did not socket my transistors.  Could it be that I damaged them while soldering?  Should I try removing the transistor and soldering a socket and THEN trying the pedal?
I'd say yes.  We haven't tried everything until we tried that, right?
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: EBK on March 14, 2017, 03:24:57 PM
I'm looking at that transistor arrangement.....
Does that cap really have a discharge path other than through the transistor?  I don't see the diode doing anything here.

Update: ok, I see that the 68k resistor is connected to the +5v node, which would eventually drop to ground potential upon power down, providing another discharge path.  I can also see how the diode can speed up the discharge once it conducts, decreasing this effective discharge path resistance.
Title: Re: &quot;Little Angel&quot; - Super Simple PT2399 Mini Chorus
Post by: jfrabat on March 14, 2017, 03:27:22 PM
OK, just to be clear then, the best way to proceed for me now would be remove the transistor (2N2222) and solder the socket and try the pedal without the transistor, or do I need to take out the 100R resistor as well?
Title: Re: &quot;Little Angel&quot; - Super Simple PT2399 Mini Chorus
Post by: EBK on March 14, 2017, 03:35:25 PM
OK, just to be clear then, the best way to proceed for me now would be remove the transistor (2N2222) and solder the socket and try the pedal without the transistor, or do I need to take out the 100R resistor as well?
Without the transistor, the 100R is already effectively disconnected.  Leave it on your board.
Title: Re: &quot;Little Angel&quot; - Super Simple PT2399 Mini Chorus
Post by: jfrabat on March 14, 2017, 03:40:34 PM
OK.  Will report tonight on the results.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: EBK on March 14, 2017, 04:09:20 PM
Indeed the 47uF may keep a small charge for a very long time after 9v power is removed.
Upon removing the 9V supply, the 7805 provides a resistive path to ground through its output terminal.  (The PT2399 possibly also provides a discharge path to ground.)
The charge would neutralize fairly quickly.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: anotherjim on March 15, 2017, 06:46:33 AM
There is a resistive path to ground in the 7805 output, but I don't know what value.
I'm still not sure having the timer threshold voltage as low as the base-emitter forward voltage be a good thing. 0.5V seems a touch low for a silicon small-signal transistor base-emitter junction, maybe that particular transistor is damaged/leaky.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: duck_arse on March 15, 2017, 09:12:22 AM
if we were to fit the reverse cap-discharge regulator diode (no. I dunno what to call it, the cap flyback preventorator?) across the regulator out to in, like in the datasheet, wouldn't that provide a [known] discharge for the offending cap?
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: EBK on March 15, 2017, 09:16:28 AM
I don't think we really care how fast it discharges, as long as it does.

More important to us is the charge time, which must be more than 400ms, I believe.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: anotherjim on March 15, 2017, 01:00:20 PM
Capacitor charge should reach 0.5v in about 350ms. That situation is complicated by the conduction "knee" of the base-emitter, which starts to take some charging current away from the capacitor before it gets clamped at the forward voltage drop - so maybe it can take 400ms. It's bit tight though isn't it?

The problem anyway with that discharge diode is that it will be "off" until the 5V supply falls sufficiently below the capacitor voltage. If the capacitor voltage is 0.5v and the diode forward voltage is 0.6v, then the 5v supply needs to fall to -0.1v, which can't happen. It's possible that the diode never conducts.

The discharge path is then via the 68k in series with whatever else goes to 0v.
If it was only 68k, and the 5v supply falls to 0v instantly (it won't), at 5 seconds after switch off the capacitor voltage is down to 0.1v. Not 0v - so I think you can fool the circuit if power goes on and off quickly enough, which is easily done when testing.

Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: jfrabat on March 16, 2017, 10:36:59 PM
Well, guys, we have still not found the problem.  Took out the transistor tonight, but no change.  Still only sending the dry signal through.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: maiko on March 17, 2017, 12:32:54 AM
Sorry to hear that
i hope you wont mind  ive taken it upon myself to check your layout against the JMK pdf all seems to
be ok but can you verify if your sockets for your ic on the solder side has continuity
to your ic legs.

If the jmk board is a dual sided board there are some soldering on your component
side that appears to be incompletly soldered.  maybe you can check that speed lug 3
in your picture there is cleary a trace from that to a 220k resistor but there doesnot
appear to be solder on the component side of the board. check and verify if there is continuity
from that to the resistor


Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: jfrabat on March 17, 2017, 09:20:19 AM
i hope you wont mind  ive taken it upon myself to check your layout against the JMK pdf all seems to
be ok but can you verify if your sockets for your ic on the solder side has continuity
to your ic legs.

I dont mind AT ALL!  IN fact, thank you!  It would not be the first time I misplace components or use the wrong ones!  This one I have tripple checked hunting down whatever it is that it is making it not work!  I will test continuity tomorrow (I'll be busy playing the guitar this evening!)

If the jmk board is a dual sided board there are some soldering on your component
side that appears to be incompletely soldered.  maybe you can check that speed lug 3
in your picture there is clearly a trace from that to a 220k resistor but there does not
appear to be solder on the component side of the board. check and verify if there is continuity
from that to the resistor

I will check all soldering where there appears to be some suspect contact on the top of the board, and re-solder those that are suspect.  I will also install the socket for the transistor (I simply uninstalled it last night, got frustrated, and left the whole thing as it was!).

Felipe
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: anotherjim on March 17, 2017, 10:41:53 AM
You know how those PT2399 are prone to stay locked up. Did you test the chip in your working delay or discharge any static after removing the transistor?
Title: Re: &quot;Little Angel&quot; - Super Simple PT2399 Mini Chorus
Post by: jfrabat on March 17, 2017, 12:10:30 PM
No, I did not...  Let me try that first.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: jfrabat on March 22, 2017, 07:25:01 PM
OK, I resoldered the spots that seemed that had no contact on the top layer, changed the PT for one on the Deep Blue Delay BB (so I could be 100% sure it worked) and tried the pedal.  No change.  This is REALLY frustrating!  Any ideas on what to check?
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: EBK on March 24, 2017, 04:22:33 PM
 What's your supply voltage measuring?
Could you double check the color bands on R8? They look off....

Did you end up socketing a replacement transistor?

Also, could you take a picture of the markings on your transistor?
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: jfrabat on March 25, 2017, 08:22:01 PM
What's your supply voltage measuring?
Could you double check the color bands on R8? They look off....


I checked the bands and its OK.  You probably noticed on a different pic the same, right?

You probably saw this one too...  But just in case.  Values are:

Battery: 9.20V

TL082:
1: 4.68V
2: 4.68
3: 4.53V
4: 0V
5: 2.80 to 3.70V
6: 2.88 to 3.65V
7: 0 to 1.4V
8: 9.20V

78L05:
IN: 9.2V
GND: 0V
OUT: 5.01V

2N2222:
C: 0V
B: 0.449V
E: 2.43V

PT2399:
1: 5.01V
2: 2.5V
3: 0V
4: 0V
5: 3.40V (should be around 2.65V)
6: 2.43V (should be 0.61V)
7: 0.875V
8: 0.995V
9 to 16: around 2.5V with movements

Did you end up socketing a replacement transistor?

Yes

(http://i46.photobucket.com/albums/f138/jfrabat/Guitar/Pedals/20170325_181004.jpg) (http://s46.photobucket.com/user/jfrabat/media/Guitar/Pedals/20170325_181004.jpg.html)

(perspective makes it look like a super tall transistor, don't it?)

Also, could you take a picture of the markings on your transistor?

Here:

(http://i46.photobucket.com/albums/f138/jfrabat/Guitar/Pedals/20170325_180010.jpg) (http://s46.photobucket.com/user/jfrabat/media/Guitar/Pedals/20170325_180010.jpg.html)
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: anotherjim on March 26, 2017, 05:16:40 AM
With power off. The transistor and the PT2399 taken out. Measure the resistance between the PT2399 socket pin 6 and pin 4.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: jfrabat on March 26, 2017, 11:36:46 AM
With power off. The transistor and the PT2399 taken out. Measure the resistance between the PT2399 socket pin 6 and pin 4.

2.2K. 

Looking at the diagram, it should be 2.2K, right?  Because the other grounds get disconnected as I take out the the transistor, right?
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: anotherjim on March 26, 2017, 01:29:28 PM
Correct, it should be 2.2k. I was asking to prove that there couldn't be a short circuit there, since removing the transistor made no difference. The PT2399 should run with 2.2k to ground from pin6, but yours doesn't seem to want to. There could still be other reasons for the fault, but I feel this should be checked out...
...so, the next thing I would do is to remove one end of that 2k2 from the board so you can temporarily solder a higher value resistor in its place - anything from 4.7k to 47k will do, just to see if you can get some delayed sound out of it. Keep the transistor removed for this test.

The Deep Blue, has a fixed resistor of 2.7k to pin6 (it's only the 2.7k when the delay pot is set to minimum resistance). I would be surprised if the difference between 2.2k and 2.7k is enough to make it work or not work, but I'd want to prove it.

Title: Re: &quot;Little Angel&quot; - Super Simple PT2399 Mini Chorus
Post by: jfrabat on March 26, 2017, 02:43:04 PM
At this point, Im willing to try anything, so thanks for the pointer.  How can I check if the signal (dry signal) is actually making it to the PT?
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: anotherjim on March 26, 2017, 04:40:50 PM
Audio probe. You should hear the input on the PT2399 pin 15. That is the point at which the input goes into the delay.

You should hear delayed signal out of its pin 12. This is where it comes out of the delay. If there is signal out of pin 12 then it is working with "some" delay.


Title: Re: &quot;Little Angel&quot; - Super Simple PT2399 Mini Chorus
Post by: jfrabat on March 26, 2017, 06:42:06 PM
I will test it tonight
Title: Re: &quot;Little Angel&quot; - Super Simple PT2399 Mini Chorus
Post by: jfrabat on May 22, 2017, 05:01:35 PM
Took a little hiatus...  Already finished an Engineers Thumb Compressor, and close to finishing a Deep Blue Delay (humidity permiting my painting it!).  Once that's all done, it's back to this one (the only one I have not gotten to work!).

Sent from my SM-G935F using Tapatalk

Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: jfrabat on June 05, 2017, 10:47:51 AM
OK, guys, I still need help on this one.  I took some time off (well, not really "off", just changed projects and made some more pedals; I actually made the Engineer's Thumb Compressor, and a Deep Blue Delay clone, both of which are working wonderfully), but considering I have 2 of these boards built, and that neither one has worked, I wanted to get back to them and finally get one of these suckers to actually work.  Plus, I could really use a Chorus on this pedal board:

(http://i46.photobucket.com/albums/f138/jfrabat/Guitar/Pedals/4c9dab8b-da1a-4b60-8b18-52c7c3ff098d.jpg) (http://s46.photobucket.com/user/jfrabat/media/Guitar/Pedals/4c9dab8b-da1a-4b60-8b18-52c7c3ff098d.jpg.html)
Got 5 pedals working (technically, 6, but I do not like the sound of the 6th); one that is not.  Not a terrible record, but lets make it better!

By the way, both the Screechy Cat and the Vulcan Rat overdrives are getting a make over and will be done in 1590B size; I have a board for a Phaser that I will build soon, and between that one and this pedal, I will need the space!  I also ordered a kit to make custom length cables to neaten everything up a bit.  I will not, however, use the old enclosure I made for the Little Angel because (1) I already used the same color for the Deep Blue Delay, and (2) I rather go smaller into the 1590B enclosure, but I will keep the same graphic style as the other one.  I'll just probably go with a metallic violet color or something along those lines...

(http://i46.photobucket.com/albums/f138/jfrabat/Guitar/Pedals/20161127_002707.jpg) (http://s46.photobucket.com/user/jfrabat/media/Guitar/Pedals/20161127_002707.jpg.html)
Old enclosure

Anyway, where do I begin to check this darned pedal? As for the PT's, I tested them all in the Deep Blue Delay (when it was in BB form; I took that apart and actually built the pedal now), and they all worked.  The issue is still that the dry signal goes through, but not the wet signal (I get no chorus effect).

Here are my voltages:

Battery: 9.20V

TL082:
1: 4.68V
2: 4.68
3: 4.53V
4: 0V
5: 2.80 to 3.70V
6: 2.88 to 3.65V
7: 0 to 1.4V
8: 9.20V

78L05:
IN: 9.2V
GND: 0V
OUT: 5.01V

2N2222:
C: 0V
B: 0.449V
E: 2.43V

PT2399:
1: 5.01V
2: 2.5V
3: 0V
4: 0V
5: 3.40V (should be around 2.65V)
6: 2.43V (should be 0.61V)
7: 0.875V
8: 0.995V
9 to 16: around 2.5V with movements

(http://i46.photobucket.com/albums/f138/jfrabat/Guitar/Pedals/20170312_101957.jpg)

(http://i46.photobucket.com/albums/f138/jfrabat/Guitar/Pedals/20170312_102122.jpg) (http://s46.photobucket.com/user/jfrabat/media/Guitar/Pedals/20170312_102122.jpg.html)

(http://i46.photobucket.com/albums/f138/jfrabat/Guitar/Pedals/20170312_102106.jpg)

(http://i46.photobucket.com/albums/f138/jfrabat/Guitar/Pedals/20170312_102056.jpg)

(http://i46.photobucket.com/albums/f138/jfrabat/Guitar/Pedals/20170312_102042.jpg)
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: EBK on June 05, 2017, 11:15:22 AM
Glad you still haven't given up on this! 

It's been a while, so we may end up rehashing stuff from before.
As for that transistor, I'm assuming the emitter is at 0V, not the collector, as you've listed it.
Title: Re: &quot;Little Angel&quot; - Super Simple PT2399 Mini Chorus
Post by: jfrabat on June 05, 2017, 11:18:16 AM
Yeah, that was a typo...

Sent from my SM-G935F using Tapatalk

Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: EBK on June 05, 2017, 11:40:04 AM
Ok.  Looks like you have the same voltage on either side of R12 (the 100R resistor).  That suggests your transistor is not conducting.  This is consistent with the base voltage being so low.  Now, why isn't that base voltage getting any higher?

A test:
With the transistor out, measure the voltage at the middle pin of that socket (where the base would go).  That node should reach about 0.7V 5V.  if it does, then I would say you have a bad transistor.
If that voltage doesn't reach 0.7V 5V, then it could be a bad cap or diode.

There may be an error on your board.  I'm going back to find the schematic....
Title: Re: &quot;Little Angel&quot; - Super Simple PT2399 Mini Chorus
Post by: jfrabat on June 05, 2017, 11:54:16 AM
OK, Thanks!  I will test tonight.

Sent from my SM-G935F using Tapatalk

Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: EBK on June 05, 2017, 12:05:34 PM
Hmm...  In the build docs for your board (http://jmkpcbs.com/wp-content/uploads/2014/10/Little-Angel.pdf), the schematic shows the diode on the base of Q1 going to ground, but other schematics show it going to +5V instead....

I've edited my test.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: jfrabat on June 05, 2017, 05:35:04 PM
You know, I never actually checked the schematics of the JMK board, but you are right.  It is different from what I have found online for the Little Angel.  This is the one I was using when I did my own board:

(http://i46.photobucket.com/albums/f138/jfrabat/Guitar/Pedals/Little%20Angel%20Miracle%203.png) (http://s46.photobucket.com/user/jfrabat/media/Guitar/Pedals/Little%20Angel%20Miracle%203.png.html)

And this is what the build docs show:

(http://i46.photobucket.com/albums/f138/jfrabat/Guitar/Pedals/Screenshot%2014.png) (http://s46.photobucket.com/user/jfrabat/media/Guitar/Pedals/Screenshot%2014.png.html)

The diode is certainly going to GND (vs 5V).  Could that be the issue?
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: EBK on June 05, 2017, 05:45:31 PM
You basically had the same exact problem with each build, whether it was your own or theirs, right?
(Their board might be correct despite their schematic error.)
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: jfrabat on June 05, 2017, 05:47:01 PM
You basically had the same exact problem with each build, whether it was your own or theirs, right?
(Their board might be correct despite their schematic error.)

Yeah, but my first board was crap, and the second one, although better, I do not feel confident that the issue was not the board.
Title: Re: &quot;Little Angel&quot; - Super Simple PT2399 Mini Chorus
Post by: jfrabat on June 05, 2017, 09:30:47 PM
Ok.  Looks like you have the same voltage on either side of R12 (the 100R resistor).  That suggests your transistor is not conducting.  This is consistent with the base voltage being so low.  Now, why isn't that base voltage getting any higher?

A test:
With the transistor out, measure the voltage at the middle pin of that socket (where the base would go).  That node should reach about 0.7V 5V.  if it does, then I would say you have a bad transistor.
If that voltage doesn't reach 0.7V 5V, then it could be a bad cap or diode.

There may be an error on your board.  I'm going back to find the schematic....
Ok, new readings of Q1 at the socket:

C: 2,43V
B: 0.455V
E: 0

This is with the 2N2222 out...

Battery measured 9V



Sent from my SGPT12 using Tapatalk

Title: Re: &quot;Little Angel&quot; - Super Simple PT2399 Mini Chorus
Post by: jfrabat on June 05, 2017, 09:36:35 PM
By the way, the 1N4148 is in fact going to ground, in case that's important...  all other readings are sa,e as above.

Sent from my SGPT12 using Tapatalk

Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: EBK on June 05, 2017, 09:40:10 PM
Hmm..  so something else (cap or diode, likely) is pulling that voltage down... We can set aside the possibility of bad transistor for now.... Edit: Hmm....
Title: Re: &quot;Little Angel&quot; - Super Simple PT2399 Mini Chorus
Post by: jfrabat on June 05, 2017, 09:53:01 PM
Audio probe. You should hear the input on the PT2399 pin 15. That is the point at which the input goes into the delay.

You should hear delayed signal out of its pin 12. This is where it comes out of the delay. If there is signal out of pin 12 then it is working with "some" delay.
I got signal in pins 9, 12, 14 and 15 (only checked that side) on the PT.  On the TL, only on pin 1... that does not sound right, though, right?

Sent from my SGPT12 using Tapatalk

Title: Re: &quot;Little Angel&quot; - Super Simple PT2399 Mini Chorus
Post by: jfrabat on June 05, 2017, 09:57:33 PM
Swaped TL082 for TL072.  still only pin 1 has signal..

Sent from my SGPT12 using Tapatalk

Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: anotherjim on June 06, 2017, 08:15:26 AM
An inverting op-amp:-
The +input (Pin3) has the DC reference voltage. No signal.
The output (Pin1) is the signal output. We expect signal.
The -input (Pin2) is a "virtual ground" if it's working properly. Would you expect signal on a ground? No signal is correct.
The input signal will be present at the input end of any resistor feeding the -input, not at the pin.

The same will be true of all the internal op-amps in the PT2399, which are all fixed as inverting. So you find signal on pin15 (output) but not on pin16 (-input).

That 1N4148 should indeed have it's cathode tied to Vb (5v). As it is, it's a coin-toss as to whether the diode or the transistor base-emitter will have the lowest forward voltage drop. If the diode's drop is higher (they often are but NOT always), it is having no effect on the transistor and not really doing anything at all. If the diode drop is lower then it will steal current from the transistor base-emitter and prevent the transistor turning on fully or never.

Please read back for the earlier trouble shooting hints. If you remember, those earlier attempts were sabotaged by faulty PT2399's.

Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: jfrabat on June 06, 2017, 09:31:01 AM
An inverting op-amp:-
The +input (Pin3) has the DC reference voltage. No signal.
The output (Pin1) is the signal output. We expect signal.
The -input (Pin2) is a "virtual ground" if it's working properly. Would you expect signal on a ground? No signal is correct.
The input signal will be present at the input end of any resistor feeding the -input, not at the pin.

The same will be true of all the internal op-amps in the PT2399, which are all fixed as inverting. So you find signal on pin15 (output) but not on pin16 (-input).

That part I get; but isn't Pin 7 also an output?  Should there not be any signal at Pin 7?  Or am I missing something?

That 1N4148 should indeed have it's cathode tied to Vb (5v). As it is, it's a coin-toss as to whether the diode or the transistor base-emitter will have the lowest forward voltage drop. If the diode's drop is higher (they often are but NOT always), it is having no effect on the transistor and not really doing anything at all. If the diode drop is lower then it will steal current from the transistor base-emitter and prevent the transistor turning on fully or never.

So, how do I test this?  Do I remove the diode and jump it to 5V?

Please read back for the earlier trouble shooting hints. If you remember, those earlier attempts were sabotaged by faulty PT2399's.

The PT's were actually all working; we thought they were faulty, but they all proved to be working when I tested them one by one in the Deep Blue Delay...
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: anotherjim on June 06, 2017, 01:21:03 PM
TL072 pin 7 is indeed an output. However, there is no audio signal feeding any of its inputs. This op-amp is part of the LFO sweep oscillator, without which, there cannot be a chorus effect.

You can remove that diode for now. It is not essential.

Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: jfrabat on June 06, 2017, 05:05:18 PM
TL072 pin 7 is indeed an output. However, there is no audio signal feeding any of its inputs. This op-amp is part of the LFO sweep oscillator, without which, there cannot be a chorus effect.

You can remove that diode for now. It is not essential.

OK, now it makes sense.  I will remove the diode and give it a go tonight.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: jfrabat on June 07, 2017, 09:50:08 PM
UPDATE: I was looking over everything, and I noticed for some reason or another, I had swapped one of the pot's pins.  I decided to just wire the pots directly to the board instead of using wires (since I am making a new enclosure anyway, it's not really worth the trouble of using wires).  Tried the board.  Same thing.

So I figured the diode could be the cause.  Un-soldered one pin and tried it.  No change.

When I went to pick up the board, I got singed by something hot.  Turns out the 78L05 was hot enough to burn.   I thought maybe it was damaged, so I replaced it.  Same result (and new one still gets as hot as the old one).

Somehow I think the 78L05 should get hot, but not THAT hot, right?  What else could be the problem here?
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: EBK on June 07, 2017, 09:53:49 PM
Hmm.... Something is drawing too much current.  This is without the transistor and without the diode?
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: jfrabat on June 07, 2017, 09:57:25 PM
Hmm.... Something is drawing too much current.  This is without the transistor and without the diode?

With transistor.  With and without diode is the same.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: EBK on June 08, 2017, 09:39:19 AM
I find myself wondering if you have bad transistors.  Does the regulator get hot without the transistor in the circuit?

Luckily, those regulators have a thermal shutdown circuit, so they should still work after burning your fingers.

If you still get a lot of heat off that regulator without the transistor, replace the electrolytic cap that connects to that diode.

Could you take a look at R8? In two of your pics, it has this hideous, pale look, but in another, it looks fine.  It's bugging me.   :icon_lol:
Title: Re: &quot;Little Angel&quot; - Super Simple PT2399 Mini Chorus
Post by: EBK on June 08, 2017, 10:23:31 AM
Ok, new readings of Q1 at the socket:

C: 2,43V
B: 0.455V
E: 0

This is with the 2N2222 out...
This is so odd.  Was this without the diode too?  If so, the only thing left is that electrolytic cap, acting like a 6k7 resistor.  Or, your 68k resistor is WAY out of spec.
Either way, they don't explain the regulator heating up.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: jfrabat on June 08, 2017, 10:57:20 AM
Ok, new readings of Q1 at the socket:

C: 2,43V
B: 0.455V
E: 0

This is with the 2N2222 out...
This is so odd.  Was this without the diode too?  If so, the only thing left is that electrolytic cap, acting like a 6k7 resistor.  Or, your 68k resistor is WAY out of spec.
Either way, they don't explain the regulator heating up.

Those readings I took with the Diode in place. 


I find myself wondering if you have bad transistors.  Does the regulator get hot without the transistor in the circuit?

Luckily, those regulators have a thermal shutdown circuit, so they should still work after burning your fingers.

If you still get a lot of heat off that regulator without the transistor, replace the electrolytic cap that connects to that diode.

Could you take a look at R8? In two of your pics, it has this hideous, pale look, but in another, it looks fine.  It's bugging me.   :icon_lol:

OK, this weekend I will try it without the transistor and see if it still gets hot.  I will also replace R8 (68K) and the cap (you are talking about C13, right?)

(http://i46.photobucket.com/albums/f138/jfrabat/Guitar/Pedals/Screenshot%2015_LI.jpg) (http://s46.photobucket.com/user/jfrabat/media/Guitar/Pedals/Screenshot%2015_LI.jpg.html)

Tonight, though, I plan to enjoy the football (as in the sport you play with your feet, not the other football that's played with your hands!) game between Costa Rica (where I live) and Panama (where I am from) for the World Cup elimination round.  GO PANAMA!
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: EBK on June 08, 2017, 11:25:31 AM

(you are talking about C13, right?)
Yes
Quote
Tonight, though, I plan to enjoy the football (as in the sport you play with your feet, not the other football that's played with your hands!) game between Costa Rica (where I live) and Panama (where I am from) for the World Cup elimination round.  GO PANAMA!
Enjoy!
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: jfrabat on October 23, 2017, 11:56:04 PM
Hi, guys.  I have been messing with a bunch of other pedals, but this one is still on my to do list.  So after 4 unsuccessful builds, I did the only reasonable thing; I ordered ANOTHER board (different supplier this time) and gave it a shot.  Unfortunately, I am getting the SAME results.  I get the dry signal coming through, but not the wet signal.

This is the board from JMKPCBs (http://jmkpcbs.com/product/little-angel/) (the one I made some time back; actually, I made 2 of these, but this is the second one):

(https://s5.postimg.org/l5ouo3vk7/20171023_213011.jpg)

This is the newer board (from DELYKPCB (http://pcb.delyk.com/modulation/10-little-angel-pcb.html)):

(https://s5.postimg.org/tnyasg9sn/20171023_212942.jpg)

I will continue troubleshooting the first one simply because I have the schematics for that one and not the new one (on these (http://jmkpcbs.com/wp-content/uploads/2014/10/Little-Angel.pdf) build docs).  Here's the schematic:

(https://s5.postimg.org/qh3r8tx2f/Little_Angel_JMK_Schematic.png)

Here is what the pedal is doing (and yes, I tried it with the guitar; there is only dry signal):



Now, last time I took voltage readings, this is what I got:

Battery: 9.20V

TL082:
1: 4.68V
2: 4.68
3: 4.53V
4: 0V
5: 2.80 to 3.70V
6: 2.88 to 3.65V
7: 0 to 1.4V
8: 9.20V

78L05:
IN: 9.2V
GND: 0V
OUT: 5.01V

2N2222:
C: 0V
B: 0.449V
E: 2.43V

PT2399:
1: 5.01V
2: 2.5V
3: 0V
4: 0V
5: 3.40V (should be around 2.65V)
6: 2.43V (should be 0.61V)
7: 0.875V
8: 0.995V
9 to 16: around 2.5V with movements

As I mentioned on the video, the 78L05 is still getting hot as well.  Also, all my PT's checked out in the Deep Blue Delay, so I know they work (at least all the chips work on the delay pedal).  Any ideas what I should look at?
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Slowpoke101 on October 24, 2017, 12:06:18 AM
Just quickly.

The first picture (the one with the two pots mounted directly to the board) has a LM13700N OTA where the PT2399 is supposed to go. What happens when a PT2399 is installed?

Any chance of some pictures of the solder sides as well?
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: jfrabat on October 24, 2017, 12:14:26 AM
Just quickly.

The first picture (the one with the two pots mounted directly to the board) has a LM13700N OTA where the PT2399 is supposed to go. What happens when a PT2399 is installed?

Any chance of some pictures of the solder sides as well?

Oh, whao... I missed that one!  Let me put the right chip in and get back to you...
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: jfrabat on October 24, 2017, 12:48:35 AM
I think I know what is going on here...

Thanks to my previous error, I unplugged the pedal, and changed chips.  Put the new chip in, but forgot to plug the battery.  Since everything was running, as soon as I plugged the battery, I put the probe on the OUT pad, and VOILA!  MODULATION!  So I ran over to my guitar, but NOTHING!  Hmmmm...  Went back to the bench, and tested the signal; no modulation.  Now, the only explanation I have is that my PT's are going into lock up.  The thing is that I have 16 of them, and they all act the same way!  Is there a way to prevent lock up?

The odd thing is that the pots do not affect the modulation I am hearing.  In all the videos I have seen when you turn the pots, the PT will make an ATARI like sound while they are moving....  But not here.  I tried to make a video, but it is difficult to note the modulation sound on the video, but there IS modulation.  That is a step forward!

I will post the video tomorrow (it is loading).  Maybe it helps (but as I said, it is hard to hear the modulation in the video).
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: Slowpoke101 on October 24, 2017, 01:12:18 AM
Just had a quick look at the smaller board. Noted the following;

R1 appears to be 68R (or is it 6R8) not 68K. D1 and Q2 may be toast.
R7 appears to be 10K not 330K
R12 is obscured and not readable. Supposed to be 4k7.
Q1 (78L05) regulator appears to be in backwards. Remove PT2399 and measure the voltage on pin1 of the socket. 5V is expected but will be much higher if in backwards.

All these observations were taken from the doco on the deluk website.

PT2399s can and do lock-up. Usually this happens when too much current is taken from pin6 before the chip has stabilized after power on. That is the reason for the delay circuit (Q2, etc) on pin6, it gives the chip a chance to stabilize.
Sometimes a locked-up chip stays that way after power down (weird but it happens). Take the chip out and short out its legs on a conductive metal plate (copper clad board is good) wait a minute and try the chip again.

Haven't checked out the first board yet (other than the LM13700 oops). I'll get there or someone else will.
Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: jfrabat on October 24, 2017, 08:14:32 AM
I think I know what is going on here...

Thanks to my previous error, I unplugged the pedal, and changed chips.  Put the new chip in, but forgot to plug the battery.  Since everything was running, as soon as I plugged the battery, I put the probe on the OUT pad, and VOILA!  MODULATION!  So I ran over to my guitar, but NOTHING!  Hmmmm...  Went back to the bench, and tested the signal; no modulation.  Now, the only explanation I have is that my PT's are going into lock up.  The thing is that I have 16 of them, and they all act the same way!  Is there a way to prevent lock up?

The odd thing is that the pots do not affect the modulation I am hearing.  In all the videos I have seen when you turn the pots, the PT will make an ATARI like sound while they are moving....  But not here.  I tried to make a video, but it is difficult to note the modulation sound on the video, but there IS modulation.  That is a step forward!

I will post the video tomorrow (it is loading).  Maybe it helps (but as I said, it is hard to hear the modulation in the video).

Hete's the video:

Title: Re: "Little Angel" - Super Simple PT2399 Mini Chorus
Post by: jfrabat on October 24, 2017, 10:01:01 AM
Just had a quick look at the smaller board. Noted the following;

R1 appears to be 68R (or is it 6R8)