Author Topic: "Little Angel" - Super Simple PT2399 Mini Chorus  (Read 498035 times)

slacker

Re: "Little Angel" - Super Simple PT2399 Mini Chorus
« Reply #440 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

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.
« Last Edit: November 28, 2010, 05:22:30 AM by slacker »

frequencycentral

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Re: "Little Angel" - Super Simple PT2399 Mini Chorus
« Reply #441 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?

Earthscum

Re: "Little Angel" - Super Simple PT2399 Mini Chorus
« Reply #442 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.
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Pigyboy

Re: "Little Angel" - Super Simple PT2399 Mini Chorus
« Reply #443 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
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Govmnt_Lacky

Re: "Little Angel" - Super Simple PT2399 Mini Chorus
« Reply #444 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
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BoxOfSnoo

Re: "Little Angel" - Super Simple PT2399 Mini Chorus
« Reply #445 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.
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tyronethebig

Re: "Little Angel" - Super Simple PT2399 Mini Chorus
« Reply #446 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)
I'm not, not licking toads!
-Homer

tyronethebig

Re: "Little Angel" - Super Simple PT2399 Mini Chorus
« Reply #447 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*
I'm not, not licking toads!
-Homer

frequencycentral

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Re: "Little Angel" - Super Simple PT2399 Mini Chorus
« Reply #448 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.

tyronethebig

Re: "Little Angel" - Super Simple PT2399 Mini Chorus
« Reply #449 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.
I'm not, not licking toads!
-Homer

tyronethebig

Re: "Little Angel" - Super Simple PT2399 Mini Chorus
« Reply #450 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.
I'm not, not licking toads!
-Homer

Pakaloabob

Re: "Little Angel" - Super Simple PT2399 Mini Chorus
« Reply #451 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.

tyronethebig

Re: "Little Angel" - Super Simple PT2399 Mini Chorus
« Reply #452 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:
I'm not, not licking toads!
-Homer

jable1066

Re: "Little Angel" - Super Simple PT2399 Mini Chorus
« Reply #453 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...

GodSaveMetal

Re: "Little Angel" - Super Simple PT2399 Mini Chorus
« Reply #454 on: December 06, 2010, 04:39:40 PM »


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

What are the level mix and delay pots?????

Earthscum

Re: "Little Angel" - Super Simple PT2399 Mini Chorus
« Reply #455 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.
Give a man Fuzz, and he'll jam for a day... teach a man how to make a Fuzz and he'll never jam again!

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GodSaveMetal

Re: "Little Angel" - Super Simple PT2399 Mini Chorus
« Reply #456 on: December 07, 2010, 04:48:17 PM »
In these mod: the pots market for DELAY, MIX and LEVEL are the correct positions?



tuckster

Re: "Little Angel" - Super Simple PT2399 Mini Chorus
« Reply #457 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?

GodSaveMetal

Re: "Little Angel" - Super Simple PT2399 Mini Chorus
« Reply #458 on: December 09, 2010, 07:34:33 AM »
I´ve made a layout for the mod of this pedal; it is correct?



GodSaveMetal

Re: "Little Angel" - Super Simple PT2399 Mini Chorus
« Reply #459 on: December 10, 2010, 09:00:07 AM »
UUUUPSS!!! some mistake; here are the correct layout, you see an error? please post it! thanks: