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DIY Stompboxes => Building your own stompbox => Topic started by: CynicalMan on October 29, 2011, 09:42:00 PM

Title: Dimension P - New PT2399 Chorus
Post by: CynicalMan on October 29, 2011, 09:42:00 PM
So, I got a Tayda order about a week ago, including some new PT2399s. Excited about my new toys, I decided to design a two voice chorus la Boss Dimension C. Having heard on this forum about how nice it sounded compared to regular choruses (mostly from Mark Hammer  ;)) , I wanted to try multiphase chorusing out for myself. It turned out well IMO, a lot lusher than single voice choruses. It's a bit too much for distortion, but the clean sounds are great.

Schematic (click for bigger image)
(http://sites.google.com/site/distorque/home/projects/pictures/Dimension P 1-0 small.png) (http://sites.google.com/site/distorque/home/projects/pictures/Dimension%20P%201-0.png)

I know it looks big, but it's really not that complicated for a chorus. It has 55 parts, compared to 48 for the Little Angel and 68 for the Small Clone. Granted, it's probably has more noise than they do, but I'm working on that.

This chorus works like the Boss DC-2, with two delay lines, one with its LFO signal inverted. This means that while one is pitch shifting up the other is pitch shifting down, and vice versa. Each of these signals is then mixed together with the dry signal. Note that the delay resistors are different, one at 270 ohms and the other at 100 ohms. This is because I was getting TZF with them at the same value, and it was making it sound too wobbly. The delay times are still close enough to get a bit of the flanger flavour as they approach each other. I've tried to keep the design as simple as possible, but there's room for further improvement and mods. I'm probably going to throw in a 1/2 Voice switch on mine, and I want to try a quadrature oscillator instead of the inverted LFO. With some clever switching, you could get a stereo/mono switch in there, with one voice and the dry signal going to each channel.

I owe a big debt to frequencycentral and anchovie for this, it's heavily influenced by both the Little Angel and the One Chip Chorus.

The circuit definitely isn't finalized yet. I'm still tweaking it, and I'm looking forward to suggestions from you guys.

Clips coming soon.
Title: Re: Dimension P - New PT2399 Chorus
Post by: electricteeth on October 30, 2011, 08:30:51 AM
Neat Neat! Looks really cool. I just ordered a bunch of those pt's in the mail! Clips?
Title: Re: Dimension P - New PT2399 Chorus
Post by: WhenBoredomPeaks on October 30, 2011, 09:06:01 AM
I was getting TZF

Whoa, i want this. I gotta order some PT2399s. I remember 2 years ago when i made my Rebote 2.5 i disliked what it did to the repeats but nowadays i am into lo-fi and sounding bad so i actually prefer it to clean digital delays. I can't wait to hear the chip in a chorus though i don't think that it will really gonna color the sound of the repeats because the delay time is really low.
Title: Re: Dimension P - New PT2399 Chorus
Post by: frequencycentral on October 30, 2011, 10:05:09 AM
Very cool! But why avoid the TZF? Why not slow the LFO down and make a feature of it?
Title: Re: Dimension P - New PT2399 Chorus
Post by: WhenBoredomPeaks on October 30, 2011, 10:30:08 AM
Very cool! But why avoid the TZF? Why not slow the LFO down and make a feature of it?

I am pretty sure that if i gonna build this i will use a 1k pot instead of one of the delay resistors. So during the pots sweep i could get TZF and bigger or smaller differences between the two stages than the stock build for possible sonic exploration.

Btw there was a topic a while ago that we should ground the delay resistor (coming from pin6) into pin4 (for lower noise) but pin 4 (digital ground) is unused here, why?

edit: here is the "digital ground and PT2399" thread: http://www.diystompboxes.com/smfforum/index.php?topic=92528.0
Title: Re: Dimension P - New PT2399 Chorus
Post by: Slade on October 30, 2011, 11:17:07 AM
Very nice! Can't wait to hear it.
Title: Re: Dimension P - New PT2399 Chorus
Post by: DougH on October 30, 2011, 12:50:14 PM
Very cool! But why avoid the TZF? Why not slow the LFO down and make a feature of it?

I am pretty sure that if i gonna build this i will use a 1k pot instead of one of the delay resistors. So during the pots sweep i could get TZF and bigger or smaller differences between the two stages than the stock build for possible sonic exploration.



There is delay control like that on the Liquiflange. When set to zero you get a nice TZF sound.

I'm really impressed with the advanced projects that have been coming out of this forum the last few years- especially the "breakthroughs" that have made some of the more complex circuits easier to build for diy-ers. Very cool.;-)
Title: Re: Dimension P - New PT2399 Chorus
Post by: CynicalMan on October 30, 2011, 02:39:19 PM
Neat Neat! Looks really cool. I just ordered a bunch of those pt's in the mail! Clips?

On their way.

I was getting TZF

Whoa, i want this. I gotta order some PT2399s. I remember 2 years ago when i made my Rebote 2.5 i disliked what it did to the repeats but nowadays i am into lo-fi and sounding bad so i actually prefer it to clean digital delays. I can't wait to hear the chip in a chorus though i don't think that it will really gonna color the sound of the repeats because the delay time is really low.

There is filtering, but no audible digital distortion. So it's not the same kind of colouring that you'd get with a rebote.

Very cool! But why avoid the TZF? Why not slow the LFO down and make a feature of it?

A few reasons. It's not really the sound I wanted for this, and it makes the LFO sound more like a full-wave rectified sine wave than a triangle wave. The flanging sound isn't that strong because there's no regeneration, it just sounds like a chorus with a throbby LFO. Dialing it in is tricky too, you have to use a trimpot or the zero crossings won't be in the middle of the LFO wave. Finally, I got a bit of a whining sound that occurred at the zero crossings, which I think is beating from the clock frequencies being so close together.

I'd like to have a go at a PT2399 flanger, but I don't know how one could manage regeneration with the 30ms latency.

I am pretty sure that if i gonna build this i will use a 1k pot instead of one of the delay resistors. So during the pots sweep i could get TZF and bigger or smaller differences between the two stages than the stock build for possible sonic exploration.

Btw there was a topic a while ago that we should ground the delay resistor (coming from pin6) into pin4 (for lower noise) but pin 4 (digital ground) is unused here, why?

edit: here is the "digital ground and PT2399" thread: http://www.diystompboxes.com/smfforum/index.php?topic=92528.0

See my above comments on the TZF. It's worth a try, but I think you'll find that it's tricky to dial in just right. What I'm saying is breadboard it first and decide for yourself.

Connecting the anti-lockup to the digital grounds made weird noises. Also, most people in the original thread (http://www.diystompboxes.com/smfforum/index.php?topic=92515.0) didn't hear a difference.


Edit: Just came across the Archangel at circuitworkshop.com. :icon_redface: For the record, I did come up with the idea independently and designed this without knowing about the Archangel. Great minds...
Title: Re: Dimension P - New PT2399 Chorus
Post by: CynicalMan on October 31, 2011, 09:12:37 AM
Made a clip:

http://sites.google.com/site/distorque/home/projects/sound-clips/dimensionpdemo.mp3

The depth is set fairly high throughout this clip. You can get subtler, more "shimmery" chorus sounds, but I wanted to show how you can have the depth set high and still not get the warbling that most choruses have. At the end, I strum a chord with the dry signal disconnected from the output. You can hear the flanging sound more prominently there.
Title: Re: Dimension P - New PT2399 Chorus
Post by: Mark Hammer on October 31, 2011, 09:16:40 AM
That's, uh, pretty dang thick.  Nice work.
Title: Re: Dimension P - New PT2399 Chorus
Post by: Thomeeque on October 31, 2011, 09:42:12 AM
Schematic (click for bigger image)
(http://sites.google.com/site/distorque/home/projects/pictures/Dimension P 1-0 small.png) (http://sites.google.com/site/distorque/home/projects/pictures/Dimension%20P%201-0.png)
...
The circuit definitely isn't finalized yet. I'm still tweaking it, and I'm looking forward to suggestions from you guys.

 As your LFO swings only cca 1VPP around 4.5V and as you filter DC part from LFO signals out, you can IMO safely use 5V source as a reference voltage for U1b inverter.

Clips coming soon.

 Would you mind to make another one with significantly less depth yet (and maybe with distorted guitar too), please? I'm fan of very light (Gilmourish if you will :)) use of chorus/flanger effects.. and maaaaybe (if it's not too much to ask already) with R5 = R2?

 Cheers, T.
Title: Re: Dimension P - New PT2399 Chorus
Post by: deadastronaut on October 31, 2011, 11:03:40 AM
nice alex, really full sounding........can you get alex lifeson to come round and play red barchetta too?.....or maybe the cult?..... ;)

this is great i just got some  pt2399's...so this is very timely....good work man... :icon_cool:
Title: Re: Dimension P - New PT2399 Chorus
Post by: slacker on October 31, 2011, 11:53:54 AM
That sounds great, nice work.
Title: Re: Dimension P - New PT2399 Chorus
Post by: DougH on October 31, 2011, 11:55:27 AM
Sounds good, even on the phone speakers!
Title: Re: Dimension P - New PT2399 Chorus
Post by: frequencycentral on October 31, 2011, 03:22:18 PM
Edit: Just came across the Archangel at circuitworkshop.com. :icon_redface: For the record, I did come up with the idea independently and designed this without knowing about the Archangel. Great minds...

 :icon_biggrin: No problem with that, yeah great minds hahaha! I assumed you'd come to it independently. They may look similar in some ways, but I think the 'intent' is what sets them apart. You were successful in your intent of a two voice chorus, I was unsuccessful in my intent of TZF. I can't remember exactly why I didn't press on with it, probably the results I got were not encouraging enough, though reading back through that post I think other stuff became priority. I'm encouraged by your work to try again someday anyway - I did draw up an Archangel 2 schematic, just never got around to trying it.
Title: Re: Dimension P - New PT2399 Chorus
Post by: Gurner on October 31, 2011, 06:57:54 PM
It has 55 parts, compared to 48 for the Little Angel and 68 for the Small Clone. Granted, it's probably has more noise than they do, but I'm working on that.

A few extra parts could be saved if you used 5V opamps, and perhaps lobbed in a 2.5V regulator (vs resistors for 1/2 VCC ref)...... also, that would have the opamps biased at 2.5V ...which is the same as the chorus IC's pin 2 ..... (you would then likely come in at under the little angel's 48  :icon_smile:)
Title: Re: Dimension P - New PT2399 Chorus
Post by: CynicalMan on October 31, 2011, 09:33:23 PM
Thanks everyone!  :)

As your LFO swings only cca 1VPP around 4.5V and as you filter DC part from LFO signals out, you can IMO safely use 5V source as a reference voltage for U1b inverter.


D'oh! Should have thought of that. Thanks for the tip.

Would you mind to make another one with significantly less depth yet (and maybe with distorted guitar too), please? I'm fan of very light (Gilmourish if you will :)) use of chorus/flanger effects.. and maaaaybe (if it's not too much to ask already) with R5 = R2?

 Cheers, T.

Here's a clip with some subtler settings:
http://sites.google.com/site/distorque/home/projects/sound-clips/dpdemo2.mp3
Light chorus - Distorted - Gilmourish. Again, I have a chord then a lick for each setting. I'll get a sample of the TZF soon. But, as I keep telling you guys, it doesn't sound that good!  ::)

A few extra parts could be saved if you used 5V opamps, and perhaps lobbed in a 2.5V regulator (vs resistors for 1/2 VCC ref)...... also, that would have the opamps biased at 2.5V ...which is the same as the chorus IC's pin 2 ..... (you would then likely come in at under the little angel's 48  :icon_smile:)

I think those parts would defeat the purpose of the simplicity. ;) Still, if we ever have another low part count FX-X...
Title: Re: Dimension P - New PT2399 Chorus
Post by: Gurner on November 01, 2011, 05:04:43 AM
A few extra parts could be saved if you used 5V opamps, and perhaps lobbed in a 2.5V regulator (vs resistors for 1/2 VCC ref)...... also, that would have the opamps biased at 2.5V ...which is the same as the chorus IC's pin 2 ..... (you would then likely come in at under the little angel's 48  :icon_smile:)

I think those parts would defeat the purpose of the simplicity. ;)

I only mentioned because you specifically touched upon parts count in your opening post ....in my books soldering one 3-legged regulator (vs 4 resistors and a few blocking caps) thereby having the whole circuit biased at 2.5V (the same as the PT2399 itself)  is more simple, but hey, I'll get me coat!
Title: Re: Dimension P - New PT2399 Chorus
Post by: CynicalMan on November 01, 2011, 07:52:45 AM
It's a good idea, but I'd prefer to stay with common parts. Also, I'm not sure if the LFO will work with a filtered Vref, it might need the resistors.
Title: Re: Dimension P - New PT2399 Chorus
Post by: culturejam on November 01, 2011, 10:46:12 AM
Wow. Very nice project!

Add another one to the list.  ;D
Title: Re: Dimension P - New PT2399 Chorus
Post by: Mark Hammer on November 01, 2011, 11:06:31 AM
If a person wanted to do TZF using a PT2399, my gut tells me that heterodyned clock noise might be less of an issue if the fixed delay were done with a BBD and the swept one done with the PT2399.  The clocks of the BBD and PT2399 are likely to be in such different regions that any sums or differences would be inaudible, in comparison to a pair of counter-swept PT2399s where the clock frequencies could get awful close sometimes.  Just a hunch.
Title: Re: Dimension P - New PT2399 Chorus
Post by: Thomeeque on November 01, 2011, 11:07:49 AM
As your LFO swings only cca 1VPP around 4.5V and as you filter DC part from LFO signals out, you can IMO safely use 5V source as a reference voltage for U1b inverter.
D'oh! Should have thought of that. Thanks for the tip.

 You're welcome! You could actually replace R10+R11 divider by single resistor (with value of parallel combination of R10 and R11 ~ 24k) hooked to 5V as well (it would introduce some slight asymmetry of LFO wave, but it's not symmetrical as it is now as well, probably due to passive integrator used).

Here's a clip with some subtler settings:
http://sites.google.com/site/distorque/home/projects/sound-clips/dpdemo2.mp3
Light chorus - Distorted - Gilmourish. Again, I have a chord then a lick for each setting.

 Thanks, quite nice (I'd prefer slower sweep yet probably, but that's just note)!

I'll get a sample of the TZF soon. But, as I keep telling you guys, it doesn't sound that good!  ::)

 I'm not that much into TZF, I was just curious how it sounds with symmetrical delay times and if there won't be some heterodinning added (you are cheating the output clock noise filtering a lot :))

 Cheers, T.
Title: Re: Dimension P - New PT2399 Chorus
Post by: CynicalMan on November 02, 2011, 08:44:36 AM
If a person wanted to do TZF using a PT2399, my gut tells me that heterodyned clock noise might be less of an issue if the fixed delay were done with a BBD and the swept one done with the PT2399.  The clocks of the BBD and PT2399 are likely to be in such different regions that any sums or differences would be inaudible, in comparison to a pair of counter-swept PT2399s where the clock frequencies could get awful close sometimes.  Just a hunch.

That would solve the heterodyning problem, but I'm still not sure if regeneration would work well with the PT2399's 30ms latency. I could be wrong, I don't know much about flangers.

You're welcome! You could actually replace R10+R11 divider by single resistor (with value of parallel combination of R10 and R11 ~ 24k) hooked to 5V as well (it would introduce some slight asymmetry of LFO wave, but it's not symmetrical as it is now as well, probably due to passive integrator used).

I'm not as sure about that change, but I'll try it out and see if it's worth saving a part.

I'm not that much into TZF, I was just curious how it sounds with symmetrical delay times and if there won't be some heterodinning added (you are cheating the output clock noise filtering a lot :))

 Cheers, T.

A bit I suppose.  ::)  I still have the 4.7n cap on the end that should reduce the clock noise by 70ish dB, but, if one wanted TZF, more filtering might get rid of the heterodyne noise.


I'm currently putting together a v1.1 schematic with a few tweaks and improvements, so stay tuned for that.
Title: Re: Dimension P - New PT2399 Chorus
Post by: alparent on November 02, 2011, 08:15:04 PM
Any layout for this one?
If not I'll make one.......just didn't want to re-invent the wheel!
Title: Re: Dimension P - New PT2399 Chorus
Post by: CynicalMan on November 02, 2011, 10:32:25 PM
As far as I know, no. You might want to wait a day or two, though, for the updates that I'm working on. A layout would be much appreciated. I'm a slow builder, and I probably won't do this one until next year, which means that I won't be making a layout right away.
Title: Re: Dimension P - New PT2399 Chorus
Post by: Ben N on November 03, 2011, 06:39:43 AM
That's lovely--not quite as lush and multi-dimensional as a DC-2, but definitely close enough for government work. The lack of LFO annoyingness makes me wonder how a vibrato setting might sound.
Title: Re: Dimension P - New PT2399 Chorus
Post by: Gordo on November 03, 2011, 01:09:15 PM
I like the fact that at lower settings it sounds a bit more like a doubler than chorus/flange.  I gotta try this one.  I've drawn up an as yet unverified board if anyone is interested.  CynicalMan I'll hold off till I have your blessing?
Title: Re: Dimension P - New PT2399 Chorus
Post by: CynicalMan on November 03, 2011, 05:01:54 PM
Go ahead, post whatever you want. I'm just saying that I'm going to be changing a few things soon, so you might want to hold off on making a layout. But if you already have one, post away.
Title: Re: Dimension P - New PT2399 Chorus
Post by: Gordo on November 04, 2011, 12:10:16 PM
I'll wait...I'm not overly thrilled with my layout anyway... :icon_confused:
Title: Re: Dimension P - New PT2399 Chorus
Post by: Tacoboy on November 04, 2011, 01:12:12 PM
Okay, some work to do this weekend. I have some unemployed PT2399's...
Title: Re: Dimension P - New PT2399 Chorus
Post by: CynicalMan on November 05, 2011, 10:59:24 AM
Here's the updated version:
(click for a bigger image)
(http://sites.google.com/site/distorque/home/projects/pictures/Dimension%20P%201-1%20small.png) (http://sites.google.com/site/distorque/home/projects/pictures/Dimension%20P%201-1.png)

No big changes. I used Thomeeque's suggestion and got rid of U1b's voltage divider. I also got rid of the cap to ground after the Depth pot, and I increased the value of the Speed control for more range.


I've also drawn up versions with mods and in stereo:

Dimension P Modded Schematic (http://sites.google.com/site/distorque/home/projects/pictures/DP%20Modded%201-1.png)

The modded version has two added switches. The Dry switch selects whether the dry signal is mixed in or not. The Voice switch chooses between 1 and 2 voices. Between these two switches, you can get vibrato, normal 1-voice chorus, 2-voice chorus, or light flanging.

Dimension P Stereo Schematic (http://sites.google.com/site/distorque/home/projects/pictures/DP%20Stereo%201-1.png)

This version is untested, but it adds a switch that should select between Mono use (with the dry signal in Output B), and Stereo chorusing, with one voice and the dry signal going to each channel.
Title: Re: Dimension P - New PT2399 Chorus
Post by: CynicalMan on November 13, 2011, 11:06:04 AM
I've set up a page with all of this info, so you can follow further developments here: http://sites.google.com/site/distorque/home/projects/dimension-p

Has anyone done a layout yet? If not, I can do one, but I'm not that good at designing nice layouts.
Title: Re: Dimension P - New PT2399 Chorus
Post by: alparent on November 14, 2011, 07:37:42 AM
I've done one.......fits in my 125B.
Only 1 jumper.

I'm no layout wiz.....

Designed in Eagle...
Woudent mind having it reviewed and revised. (I like to have all my off-board connections on the same side, but this one as them on 2 sides. Not a big deal I know!)

Not confirmed/built yet.

I want to mod the 2 switches (voices and dry signal) with pots to blend rather then just in or out.
Title: Re: Dimension P - New PT2399 Chorus
Post by: roseblood11 on November 14, 2011, 06:01:36 PM
This is one of the most interesting projects that I found here over the last few years. Many thanks for sharing!!!  :) :) :)

Has anyone done a layout yet?

I think of doing a veroboard layout for a 1590BB enclosure.

What about a version that includes all the possibilities of the "modded" and the "stereo" version?
Can you post sound clips that demonstrate the mods?

regards, Immo
Title: Re: Dimension P - New PT2399 Chorus
Post by: CynicalMan on November 14, 2011, 06:49:47 PM
I've done one.......fits in my 125B.
Only 1 jumper.

I'm no layout wiz.....

Designed in Eagle...
Woudent mind having it reviewed and revised. (I like to have all my off-board connections on the same side, but this one as them on 2 sides. Not a big deal I know!)

Not confirmed/built yet.

I want to mod the 2 switches (voices and dry signal) with pots to blend rather then just in or out.

I'm a jumper junkie.  ;) I can't get rid of them. I can take a look at your layout, however.

You could probably do the pot thing, just replace the switches with pots wired as variable resistors. 100kA would be my recommendation, but I haven't tried that out. I'm not sure how useful the pots would be, but it's worth a try.



I think of doing a veroboard layout for a 1590BB enclosure.

What about a version that includes all the possibilities of the "modded" and the "stereo" version?
Can you post sound clips that demonstrate the mods?

regards, Immo

A vero layout would be great. I'm planning to build on vero, although I was going to try a 1590B.

I'm personally planning to build a modded stereo version with three switches. I just didn't put it up because I wanted to limit the number of schematics that I put up. The mods are pretty simple, and I figured people could mix and match at their leisure.

The first sound clip has the dry signal cut out at the very end. I can do clips of the other mods if you want, although that's the most unusual one.
Title: Re: Dimension P - New PT2399 Chorus
Post by: deadastronaut on November 15, 2011, 03:35:28 AM
+1 on 1590b... ;)
Title: Re: Dimension P - New PT2399 Chorus
Post by: CynicalMan on November 16, 2011, 05:39:23 PM
Here's a clip of the mods:
http://sites.google.com/site/distorque/home/projects/sound-clips/dpmods.mp3

Two voices, dry on - One voice, dry on - Two voices, dry off - One voice, dry off

Normal - Light Chorus - Flanger - Vibrato
Title: Re: Dimension P - New PT2399 Chorus
Post by: roseblood11 on November 17, 2011, 10:35:05 AM
I'm personally planning to build a modded stereo version with three switches. I just didn't put it up because I wanted to limit the number of schematics that I put up. The mods are pretty simple, and I figured people could mix and match at their leisure.

But that would be the most interesting version. And when somebody posts a vero layout for it, it will be good to have the schematic...

Great soundclip, thanx! The mods sound really usefull.
Title: Re: Dimension P - New PT2399 Chorus
Post by: frequencycentral on November 17, 2011, 12:37:31 PM
Just a couple of thoughts to ponder on multiple PT2399 designs:

- it would appear from recent reseach that pins 3 and 4 are connected internally by a low value resistor. If you look at the example circuits on the PT2399 datasheet, the delay pot is connected to digital ground. So maybe connect the anti lock up circuit should be referenced to pin 4 rather than to ground.

- it would further appear from recent reseach that the PT2399 dumps a load of hash into the 5v supply rail, so the 5v supply rail should not really be used as a convenient vref for other stuff (not that Alex has done this). So, as the PT2399 is dumping hash - would it not make sense in a multiple PT2399 delay to use a seperate 7805 for each PT2399, thus further isolating and reducing hash?
Title: Re: Dimension P - New PT2399 Chorus
Post by: Suicufnoc on November 17, 2011, 12:56:25 PM
- it would appear from recent reseach that pins 3 and 4 are connected internally by a low value resistor. If you look at the example circuits on the PT2399 datasheet, the delay pot is connected to digital ground. So maybe connect the anti lock up circuit should be referenced to pin 4 rather than to ground.
Seems like I read somewhere that someone tried this on the Little Angel and had problems, but I may be wrong.

- it would further appear from recent reseach that the PT2399 dumps a load of hash into the 5v supply rail, so the 5v supply rail should not really be used as a convenient vref for other stuff (not that Alex has done this). So, as the PT2399 is dumping hash - would it not make sense in a multiple PT2399 delay to use a seperate 7805 for each PT2399, thus further isolating and reducing hash?
Maybe it would be enough to isolate each chip with say a 100 ohm resistor from the 7805 and its own filter cap?
Title: Re: Dimension P - New PT2399 Chorus
Post by: CynicalMan on November 17, 2011, 04:15:21 PM
Just a couple of thoughts to ponder on multiple PT2399 designs:

- it would appear from recent reseach that pins 3 and 4 are connected internally by a low value resistor. If you look at the example circuits on the PT2399 datasheet, the delay pot is connected to digital ground. So maybe connect the anti lock up circuit should be referenced to pin 4 rather than to ground.

I tried that and I didn't hear any improvement. Merlin tested using pin 4 instead of ground in a normal PT2399 circuit and he didn't see any noise improvement. It could be one of those weird variances between chips. Anyway, it works with that fix, but I left it out because I thought layouts would be easier with the anti-lockup going to ground. You can do it either way.

- it would further appear from recent reseach that the PT2399 dumps a load of hash into the 5v supply rail, so the 5v supply rail should not really be used as a convenient vref for other stuff (not that Alex has done this). So, as the PT2399 is dumping hash - would it not make sense in a multiple PT2399 delay to use a seperate 7805 for each PT2399, thus further isolating and reducing hash?

I didn't know this, but I'll look into filtering. Hopefully I can get improvements without using another 7805. I am using the 5V line with the LFO inverter, but that's not in the signal path so it shouldn't add noise (I think).

I'm also looking at the pre-emphasis thread, so I'll run some real noise tests tomorrow and try these out..
Title: Re: Dimension P - New PT2399 Chorus
Post by: alparent on November 18, 2011, 07:27:34 AM
I'm using a real Vr (as per your original schematic) to feed the inverter, my buffer stage and mixing stage.

Schematic is done...box art is done....layout......(not quite there yet  :icon_redface:)

I've added an input buffer, a mixing stage that will receive (Dry, Voice1 and Voice2) also adding a 160Ω in parallele with the 270Ω via a switch to bring it to 100Ω to get some TZF.

All this will fit in my 125B.
Title: Re: Dimension P - New PT2399 Chorus
Post by: Gordo on November 18, 2011, 11:39:17 AM
This layout is unverified so let me know if you try it.  I'll try to etch the board over the weekend and so how it goes.  Based on CynicalMan's 1.1 version.

http://dl.gordomusic.com/DIYStompboxes/Dimension_P_layout.pdf (http://dl.gordomusic.com/DIYStompboxes/Dimension_P_layout.pdf)
http://dl.gordomusic.com/DIYStompboxes/Dimension_P_scheme.pdf (http://dl.gordomusic.com/DIYStompboxes/Dimension_P_scheme.pdf)
http://dl.gordomusic.com/DIYStompboxes/Dimension_P_pcb.pdf (http://dl.gordomusic.com/DIYStompboxes/Dimension_P_pcb.pdf)
Title: Re: Dimension P - New PT2399 Chorus
Post by: alparent on November 18, 2011, 01:08:09 PM
Thanks for that Gordo.

If you don't mind.....I'll use your layout as inspiration for my incarnation of this project.
Title: Re: Dimension P - New PT2399 Chorus
Post by: Gordo on November 18, 2011, 02:32:36 PM
My pleasure, I'll post the Eagles if you'd like.

Here's the ground pour version of the board
http://dl.gordomusic.com/DIYStompboxes/Dimension_P_pcb_gnd.pdf (http://dl.gordomusic.com/DIYStompboxes/Dimension_P_pcb_gnd.pdf)
Title: Re: Dimension P - New PT2399 Chorus
Post by: CynicalMan on November 20, 2011, 06:47:39 PM
Nice layouts! Good luck with the PCB.

I tested the 5V supply noise, and there wasn't any more with two PT2399s than there was with only one. There was very little high frequency noise in general, much more 60Hz and LFO noise. Which isn't to say there was a lot of those, but the digital noise was much smaller still. It was only 3dB higher than the base noise of my audio interface.

Has anyone built or breadboarded this yet? I'm curious about your thoughts on the sound.
Title: Re: Dimension P - New PT2399 Chorus
Post by: alparent on November 21, 2011, 07:33:18 AM
I'm at attempt #6 of a PCB layout of my incarnation of this. :icon_redface: :'(
Attempt #7 might be the good one.

Can't wait to build this!
Title: Re: Dimension P - New PT2399 Chorus
Post by: alparent on November 28, 2011, 10:59:40 AM
OK PCB done (I needed to fits everything on a 2" X 3" board), etched, drilled, thinned.......now need to populate it.

Can't wait to ear it.
Title: Re: Dimension P - New PT2399 Chorus
Post by: CynicalMan on November 28, 2011, 09:55:59 PM
Wow, not bad.
Let us know how it turns out!
Title: Re: Dimension P - New PT2399 Chorus
Post by: Seven64 on December 14, 2011, 06:24:16 PM
updates?
Title: Re: Dimension P - New PT2399 Chorus
Post by: alparent on December 14, 2011, 06:40:28 PM
Board populated......will finish this during my Christmas holidays (hopefully)

Redoing the bedroom......not much free time....

No worries I will post my progresses   :icon_biggrin:
Title: Re: Dimension P - New PT2399 Chorus
Post by: sundgist on December 15, 2011, 07:31:48 PM
Using the stereo version and adding a dpdt (on/off/on) after R17/R23 (jumper switch contacts 1&3 on the R17 side) and changing the mono/stereo switch to (on/off/on) would give you the best of both versions. Loads of output configurations possible with only 2 switches.

(http://dl.dropbox.com/u/15632336/lektronix/StompFX/Dimension%20P/Dimension%20P%20%28best%20of%20both%29%20Schematic.bmp)

In Mono mode you have:
2 voice + dry at out A (dry only at out B)
2 voice wet only at out A (nothing at out B)
2 voice wet only at out A (dry only at out B)

With mono/stereo in the middle (off) position:
1 voice + dry at out A (dry only at out B)
1 voice wet only at out A (nothing at out B)
1 voice wet only at out A (dry only at out B)

In Stereo mode you have
2 Voice + dry in stereo using both outs (or 1 voice + dry if only using one output)
2 Voice wet only in stereo using both outs (or 1 voice wet only if only using one output)
2 Voice wet only in stereo at both outs with dry at out B only.

Hope that all makes sense. Not sure how useful the last one is?

I will be knocking up a vero layout of this quite soon.
Title: Re: Dimension P - New PT2399 Chorus
Post by: CynicalMan on December 15, 2011, 10:25:51 PM
That's neat. I figured that there were 6 'useful' positions myself:

Both voices with Dry
1 voice with Dry
Both voices without Dry
1 voices without Dry
Stereo with Dry
Stereo without Dry

But I couldn't find a way to do it with two switches. I was planning to use three on/on switches with redundant positions, but your system is better.


@ Alain,
I just noticed a potential issue with your setup. If you use pots instead of switches, that could reduce the cutoff of the output low pass filter. You might want to reduce the value of the 4.7n capacitors or omit them altogether if you haven't already.
Title: Re: Dimension P - New PT2399 Chorus
Post by: alparent on December 16, 2011, 10:10:35 AM
Ok will keep an eye on that.
Thanks
Title: Re: Dimension P - New PT2399 Chorus
Post by: sundgist on December 17, 2011, 08:13:09 PM
Just finished putting this vero layout together. Based on the Stereo schematic with my "best of both" switching from a few posts above.
Component labels follow the schematic. Due to the software the component list is not in order and R1=1M has dropped off the bottom.
Havn't had a chance to check over it so there may be some mistakes. I will update this post for any corrections and verifications.

(http://dl.dropbox.com/u/15632336/lektronix/StompFX/Dimension%20P/Dimension%20P%20stripboard.gif)

note: one or both of the pots function may be reversed.

A better view of the cuts and jumpers

(http://dl.dropbox.com/u/15632336/lektronix/StompFX/Dimension%20P/Dimension%20P%20stripboard%20cuts.gif)
Title: Re: Dimension P - New PT2399 Chorus
Post by: roseblood11 on December 18, 2011, 04:17:38 PM
(http://banaterschwabenforum.phpbb6.de/images/smiles/bravo_gemacht.gif)
Title: Re: Dimension P - New PT2399 Chorus
Post by: sundgist on December 18, 2011, 05:42:40 PM
Thanks...  :icon_redface:
Noticed a few errors that I'm going over at the moment. I'll update a bit later.

edit: Fixed a few mistakes, layout above now updated.
Title: Re: Dimension P - New PT2399 Chorus
Post by: sundgist on December 22, 2011, 05:47:02 PM
(http://dl.dropbox.com/u/15632336/lektronix/Photos/Dimension%20P%20vero.jpg)

Just finished populating my vero. Gets pretty tight but do-able as long as your caps aren't too big.
The board itself will fit in a 1590b but I'm not going to attempt to squeeze sockets, pots and switches in with it.

Hopefully, I'll get the wiring, pots and switches on tomorrow and see if it works.

Does anyone know how much current is drawn from the 5v regulator? I wouldn't mind using the smaller TO-92 package but the ones I have are max 140mA.
Title: Re: Dimension P - New PT2399 Chorus
Post by: egasimus on December 22, 2011, 05:51:31 PM
That's a neat vero! Every time I look at a DIYLC vero layout, those things look horribly messy and a waste of space; but, seeing how tight they turn out in practice, I might just save myself etching a PCB and building this on vero... looks great!
Title: Re: Dimension P - New PT2399 Chorus
Post by: CynicalMan on December 22, 2011, 06:05:33 PM
I took a quick look at your vero, and I did notice a couple of minor errors. I'll try to take a closer look tonight.
The input of Delay 2 is connected directly to the input instead of after the input capacitor. The quick fix would be to replace the jumper from D20 to K20 with a 0.1uF capacitor.
I'm not sure which side of the pots the layout is supposed to show, but make sure to use pins 2 and 3 on both pots.

I'm not sure about the current draw. The regulator does get warm. I can't see it using 140mA but I could be wrong.

Otherwise, it looks great!
Title: Re: Dimension P - New PT2399 Chorus
Post by: sundgist on December 22, 2011, 07:00:44 PM
The input of Delay 2 is connected directly to the input instead of after the input capacitor. The quick fix would be to replace the jumper from D20 to K20 with a 0.1uF capacitor.

Input is on (L20) goes via C1 to (K16). There it splits to R4(K15) and jumper(K20)/R7(D18) to the delay inputs.

Quote
I'm not sure which side of the pots the layout is supposed to show, but make sure to use pins 2 and 3 on both pots.


Apart from the wiper on pin 2, pot pins are a bit of a guessing game for me. Thanks, I'll update the layout.

@egasimus : Thanks   :icon_redface:
Title: Re: Dimension P - New PT2399 Chorus
Post by: CynicalMan on December 22, 2011, 07:14:22 PM
Ah, sorry about the first one, I forgot to get the updated pic.
Title: Re: Dimension P - New PT2399 Chorus
Post by: sundgist on December 23, 2011, 06:41:38 PM
So I finished building this and it worked.....   :icon_biggrin:       at least for a few minutes!   >:(

There was a lot of noise from the output of delay 1. I checked voltages and pins 5,6,7 & 8 were quite different to those of delay 2. Whilst probing around debugging I managed to short something and out came the magic smoke. The regulator got pretty hot, thats had it.

Taking a break before getting back to it. It did sound nice while it lasted...  :'(

This is the biggest problem with a tightly packed vero layout. Debugging is a pain in the butt.

edit: I think I found the culprit causing the noise. Whilst preparing the board I put a cut in the wrong place. I made a mental note at the time that I would need to move c2 and c3 over. I guess my mental notes are of the wipe clean variety!
I noted the current draw from my 9v supply was 70mA so I guess using the TO-92 package regulator would be fine.
Looks like this should work once I swap out the burnt regulator and check if anything else got damaged. Hopefully I can verify this layout pretty soon.
Title: Re: Dimension P - New PT2399 Chorus
Post by: sundgist on December 23, 2011, 09:41:55 PM
Vero layout is now verified working.

And very nice it sounds too. Good one CynicalMan. If you've got two amps this does sound really lush in stereo.

TO-92 packaged regulator seems to work fine. Mine is max 140mA. On switching on, the current draw on my 9v supply jumps up to around 200mA before settling rather quickly at 60-70mA. I suppose this would be the power supply caps charging up, I doubt the regulator sees that much current.
I've used a 500k pot for speed, all I had to hand. At it's slowest, without the dry sound, you can't notice any modulation just a detuning effect which is adjustable with the depth pot. This sounds best in stereo.
I've socketed R2. I fancy playing around with a pot in it's place just to see what sounds it can make.
Title: Re: Dimension P - New PT2399 Chorus
Post by: sundgist on December 24, 2011, 08:26:22 PM
Been playing with this a bit more.

A 10k pot in series with R2 gives a modulated slapback echo at max and stock chorus at min. There's a nice variety of sounds here with the different switching options.
I wouldn't go any bigger than 10k as noise starts to creep in above that. You could change R2 to 100R and have TZF at the pots min though I did find it gets quite whiney.
I'm keeping the 500k pot for speed. I like the double tracking effect when this is maxed, even more so with a longer delay.

In the end you get:

1 & 2 voice chorus, vibrato, slapback echo and stereo double tracking.

Not a bad little box of tricks.

Title: Re: Dimension P - New PT2399 Chorus
Post by: roseblood11 on December 27, 2011, 05:17:37 PM
what taper would you recommend for that extra 10k pot? I'm just placing my order...
Title: Re: Dimension P - New PT2399 Chorus
Post by: sundgist on December 27, 2011, 05:44:28 PM
A linear pot was all I had and works fine.
Title: Re: Dimension P - New PT2399 Chorus
Post by: Gordo on January 07, 2012, 07:22:47 PM
Verified my layout but note if you're using the L78L05 the regulator needs to be spun 180 degrees from how I drew it.  Nice one Cynicalman, I'm going to play around a bit with the delay resistors just because I can't leave well enough alone.  Then again that's what got me here in the first place  :icon_smile:

Not my tightest layout but easy to work on.
Title: Re: Dimension P - New PT2399 Chorus
Post by: CynicalMan on January 07, 2012, 09:41:10 PM
Glad that people are liking this! I'm waiting on an order from PPP to finish a Tremulus Lune, but once I'm done that I'll start on my build. I'll probably do a modified version of sudgist's layout; the vero board I have from Tayda is only 19 holes tall. And I'll play around with that delay resistor mod. Once I heard about that I started thinking about making some giant Echo Base/Dimension P mutant, but I don't really need that wacky a pedal.  ;) (Although if I did, I might have thrown in a Clari(not) envelope follower too.)
Title: Re: Dimension P - New PT2399 Chorus
Post by: roseblood11 on February 05, 2012, 12:59:47 PM
How ould the bypass wiring look like for the version that the vero layout is based on?
The bypass signal has to go to both outputs, so I guess it has to be a buffered bypass?
Title: Re: Dimension P - New PT2399 Chorus
Post by: frequencycentral on February 05, 2012, 01:10:05 PM
^^^

You're an actress??
Title: Re: Dimension P - New PT2399 Chorus
Post by: CynicalMan on February 05, 2012, 03:37:17 PM
It's up to you. If you don't need stereo when bypassed, you could just wire the second output right to the circuit. If you wanted stereo bypass, you could buffer both channels, just buffer the second output, or have both channels connected when bypassed. This last one might cause issues with pedals with low input impedances if you're using it as a splitter, but for the most part it should be fine. If you want to use a 3PDT and an LED, you'll probably have to use a Millennium Bypass so that you can use one of the poles for each output.

Martin, how did you wire the bypass? Also, do you mind if I post your switching scheme on my site?
Title: Re: Dimension P - New PT2399 Chorus
Post by: sundgist on February 06, 2012, 07:24:44 PM
Quote
Martin, how did you wire the bypass?

I havn't yet.... I don't have any enclosures or footswitches at the moment, but I've been pondering the stereo bypass. I found a switching schem for a 3pdt, which connects both channels in bypass (splitter) and allows the use of a mill bypass for led, either here or at the other forum. Hadn't thought about the need for buffers. I think the only things I would have plugged in after this would be my stereo rackmount effects or direct to mixer both of which have buffered inputs anyway.

Ok, found the thread. http://www.diystompboxes.com/smfforum/index.php?topic=95532.0 (http://www.diystompboxes.com/smfforum/index.php?topic=95532.0)

Quote
Also, do you mind if I post your switching scheme on my site?

Please feel free.
Title: Re: Dimension P - New PT2399 Chorus
Post by: roseblood11 on April 09, 2012, 08:07:59 AM
I built the "best of both" version, using sundgists veroboard layout. I also did both mods that he suggested (500k speed pot and that extra 10k pot in series with R2).
The circuit works, but it has noise problems. It's interesting that the outputs of both delays have a bit different noises: What comes from delay2 I would describe as "whining", whereas delay 1 produces white noise, but both noise sounds follow the lfo frequency.

- I wonder why the LFO inverter gets its Vref from the 7805. Wouldn't it be better to give it it's own voltage divider or at least share the voltage divider with the other half of the TL072?

- I don't understand why R23 is connected to R3/C6. Why not to R6/C11? Wouldn't that improve the decoupling of both outputs?

- Is it possible that the extra 10k pot in series with R2 produces the noise? (I used quite long wires...)  I connected it between R2 and the PT2399, maybe it would be better to move it to the other side of R2 (= between R2 and AL)?

btw: I made a little extra board with two output buffers and a millenium 2 bypass. I'll post that later.
Title: Re: Dimension P - New PT2399 Chorus
Post by: CynicalMan on April 12, 2012, 08:38:24 PM
Where did you get your PT2399s? I've had similar issues with low-quality PT2399s from Tayda, but other vendors might have problems too.

- I wonder why the LFO inverter gets its Vref from the 7805. Wouldn't it be better to give it it's own voltage divider or at least share the voltage divider with the other half of the TL072?

U1a doesn't have a stable reference voltage source. The voltage on its non-inverting input varies quite a bit with the LFO signal because there's no capacitor filtering out the AC. I used the 5V source because it was convenient. The current going into the TL072 will be tiny, it shouldn't affect the power at all.

- I don't understand why R23 is connected to R3/C6. Why not to R6/C11? Wouldn't that improve the decoupling of both outputs?

It could be connected to either, the signal at both should be the same. I don't think that will affect the noise, though.

- Is it possible that the extra 10k pot in series with R2 produces the noise? (I used quite long wires...)  I connected it between R2 and the PT2399, maybe it would be better to move it to the other side of R2 (= between R2 and AL)?

That shouldn't matter either. If you want to check, just put a jumper across the pot and see if that helps, but I doubt it will.

btw: I made a little extra board with two output buffers and a millenium 2 bypass. I'll post that later.

Nice, I'm interested in seeing that. I was about to put Martin's mods on my site, but then I realized that I didn't have a stereo bypass system designed. I was thinking of something Millennium-based too. I still haven't built mine, but I plan to build it sometime in the next couple of months.
Title: Re: Dimension P - New PT2399 Chorus
Post by: roseblood11 on April 13, 2012, 01:00:33 PM
Still fighting the lfo noise... Maybe  I really have to buy some other PT2399s.

The depth pot makes some crackling noise when it's turned, is that normal?

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

This is a little add-on board with stereo output buffer and millenium 2 bypass switching:
I used a TLC2272

(http://forum.musikding.de/cpg/albums/userpics/23524/bufferboard_final.gif)
Title: Re: Dimension P - New PT2399 Chorus
Post by: Xavier on May 08, 2012, 04:11:32 AM
First, thanks Cynicalman for a GREAT project...........I am building this one shortly............

I only have a question about the stere version. SInce i have always used a stereo rig, in my case it's going to be ALWAYS in stereo, ...........will I still have signal through both outputs when the circuit is in bypass mode ? or only when the effect is on ?
Title: Re: Dimension P - New PT2399 Chorus
Post by: roseblood11 on May 08, 2012, 11:02:09 AM
That depends on the bypass wiring, which isn't included in the schematic at all. If you do it as I suggested directly above your post, you'll always have a signal at both outputs. I know that the layout of the output buffer circuit looks horrible, but it is small: I made it that way to fit between the footswitch/input jack (on the right side of the enclosure) and the two output jacks on the other side - in a 1590B.
Title: Re: Dimension P - New PT2399 Chorus
Post by: CynicalMan on May 09, 2012, 09:22:23 PM
Yeah, I haven't really figured out the stereo bypass wiring. I suggested stereo as a mod to the original mono version, but I haven't got around to looking at bypass. I'd suggest looking at roseblood's bypass scheme, as well as the variety of threads that you can find here by searching "stereo bypass". You can either use buffers or use a 4PDT and Millenium Bypass. I was thinking of using the buffered signal at pin 15 of one of the PT2399s, but it has a slight boost so you'd need a voltage divider to bring it down to unity gain.
Title: Re: Dimension P - New PT2399 Chorus
Post by: GaryB on July 24, 2012, 04:49:28 PM
Hi,
Lovely job CynicalMan, it seems to be just what I have been looking for.
A couple of possibilities come to mind though.
The LFO may be enhanced if something like the XR2206 function generator is used.
This device gives sine/triangle/square/ramp wave outputs with low distortion and a wide sweep range.
Unfortunately it needs a minimum 10V supply, but still might be food for thought.
Alternatively a small pic could be used as a function generator, the 12F675 or 12F683 comes to mind.
Also do you know about the microchip mcp6001/2/4 op amp?
5V operation, rail to rail input and output, high gain and very quiet.
I have used them successfully in a distortion/overdrive stomp box and they may possibly be better suited for the LFO and inverter than the TL072.
I know that I am entering this discussion late and I hope that these suggestions are not annoying.
Cheers
Title: Re: Dimension P - New PT2399 Chorus
Post by: nocentelli on July 24, 2012, 07:44:31 PM
The 2206 seems to work on 9v in the catalinbread pareidolia - maybe at reduced performance as it's only producing a single simple waveform?
Title: Re: Dimension P - New PT2399 Chorus
Post by: roseblood11 on October 17, 2012, 07:20:35 AM
I still can't get rid of the background noise. There's too much constant hiss and noise that changes with the lfo.

What I did:
-tried more than 25 different PT2399 from 4 different suppliers
-added an extra voltage divider (from 9V source) for the LFO inverter (to decouple it from the 5V supply rail)
-tried different 5V regulators.

What else could I do?
-Maybe use better parts for C16 and C19? (I used cheap parts from tayda for everything)
-Increase the values of C18 and C20?
-Add a 100R resistor before the 7805?
-use shielded wire for the pots (but the noise doesn't change if I move the wires)?

I still don't understand, how the noise gets into the audio signal...

I built the "best of both" version using sundgist's vero layout and added two output buffers, wired as shown above (where I posted the vero layout of the buffer).
Title: Re: Dimension P - New PT2399 Chorus
Post by: samhay on October 17, 2012, 03:56:23 PM
I also built the 'best of both' version recently using sundgist's vero layout. Thanks CynicalMan and sundgist - nice job.
It sounds good - very lush - and there are no major noise issues (for a PT2399 build). I added a switchable 50k delay pot to the 1st delay chip, which adds yet another dimension (pun intended). I also added a mono A/B output selector switch and the only issue I have with it is that there are too many options available - I don't do too well with making choices.
roseblood11: My version is true bypass - mono in/stereo out with a Millennium bypass using a 3pdt. Have you tried removing the output buffers?
Title: Re: Dimension P - New PT2399 Chorus
Post by: roseblood11 on October 17, 2012, 06:10:52 PM
Have you tried removing the output buffers?

No, but how should they cause this noise? If the lfo noise would find its way into the buffers via the supply rail, it would be audible in bypass mode, which is not the case.
Title: Re: Dimension P - New PT2399 Chorus
Post by: samhay on October 18, 2012, 06:14:26 PM
Ah sorry, I missed the fact that the noise changes with the lfo.
I am using a 78L05 regulator (it doesn't get very hot), as was Gordo I think. The filtering may be a little different for a 78L05 vs 7805, but the caps seem oversize anyway. I guess you have tried a few different op amps?
Title: Re: Dimension P - New PT2399 Chorus
Post by: bluebunny on January 04, 2013, 11:28:01 AM
Just built mine (see Pictures (http://www.diystompboxes.com/smfforum/index.php?topic=36392.msg887288;topicseen#msg887288) thread), and it sounds great.  I've gone for the modded v1.1 circuit, with switches for dry on/off and 1/2 voices.

Thanks Alex!
Title: Re: Dimension P - New PT2399 Chorus
Post by: axelrod on February 14, 2013, 08:34:51 PM
 Nice sounding chorus , but I have a fair amount of hiss and LFO noise . I would give up features for less noise if possible . I used the best of both vero . How much noise is normal for a PT2399 ?
Thanks
Title: Re: Dimension P - New PT2399 Chorus
Post by: samhay on February 15, 2013, 03:30:19 AM
The PT2399 gets progressively noisier the longer the delay time. In this circuit, it shouldn't be a problem. Seeing as roseblood11 has had problems too, it would seem that there is something going on though.
Title: Re: Dimension P - New PT2399 Chorus
Post by: axelrod on February 15, 2013, 01:56:34 PM
So far I played with different power supplies ,PT2399's , some TL072's , replaced the 78L05 for a 7805 and added a voltage divider for pin 5 of the TL072 . A lot of hiss is gone  but the chewing of the LFO is still present . I'm thinking more ,better filtering but don't really know ...
Title: Re: Dimension P - New PT2399 Chorus
Post by: chemosis on February 27, 2020, 09:06:28 PM
noob question. how does one wire the switches since theres only 4 wires for the 2 spdt switches?
Title: Re: Dimension P - New PT2399 Chorus
Post by: chemosis on February 27, 2020, 09:09:45 PM
if they were spst switches then id understand but since there spdt switches I don't understand because that would be 4 wires for 6 terminals
Title: Re: Dimension P - New PT2399 Chorus
Post by: jpalmer5948@gmail.com on February 27, 2020, 11:44:37 PM
there are many very good diagrams showing 3pdt or dpdt switches...look at guitar pcb, they have alot of good info in their instructables...as well as circuit parallels and series/mods...
Title: Re: Dimension P - New PT2399 Chorus
Post by: paderuski on May 07, 2020, 10:57:03 AM
I made the mono version 1.1 with the two switches for voicing and dry control. No noise issues to note but I was wondering if there was a simple way to increase the delay time without impacting on the performance of the circuit? I would assume its to do with the delay resistors and changing the values a bit. I wanna achieve more of an echo-like effect or get more voices on there somehow. However, more voices probably requires more PT2399s which might be a hassle on the veroboard circuit I already made. 

Thanks very much for the circuit diagram, it made things an awful lot easier for me.
Title: Re: Dimension P - New PT2399 Chorus
Post by: John Lyons on January 13, 2022, 06:16:28 PM
Anyone have the Schematic(s) for this?
Title: Re: Dimension P - New PT2399 Chorus
Post by: Ben N on January 13, 2022, 07:44:48 PM
Anyone have the Schematic(s) for this?
There are live links for schem, layout on p. 3 of the thread. Cheers, John!
Title: Re: Dimension P - New PT2399 Chorus
Post by: John Lyons on January 13, 2022, 08:58:26 PM
Oh,ok. I glossed over those. Thanks.
Title: Re: Dimension P - New PT2399 Chorus
Post by: bluebunny on January 14, 2022, 04:30:39 AM
In case you just need some images, here are the originals from my stash:

v1.0

(https://i.imgur.com/JCZ57hU.png)

v1.1

(https://i.imgur.com/RKhDGrX.png)

v1.1 stereo

(https://i.imgur.com/SXjoxQ7.png)

v1.1 modded

(https://i.imgur.com/LWJjDou.png)

^^ I've built this last one a number of times.
Title: Re: Dimension P - New PT2399 Chorus
Post by: Ben N on January 14, 2022, 05:52:41 AM
I don't know if this is really the place to mention this, but asbestosaurus at the "other" forum just posted a simple chorus design using the Mitsubishi M65850P, an out-of-production but still available  cheap, digital delay chip with 15-200ms delay intended for karaoke machines--not much good for an echo, but maybe ideal for ADT/chorus/vibrato/reverb with that super-short low-end range. Might make for some excellent possibilities.
Title: Re: Dimension P - New PT2399 Chorus
Post by: John Lyons on January 23, 2022, 09:55:45 PM
Thanks for posting those Schematics Marc!
I'll check that project out Ben.