Wednesday, 29 February 2012

Little Angel Chorus - Rick Holt (frequencycentral)

Another great sounding circuit here from Rick.  His explanation:

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.

Those familiar with the PT2399 family of delays will recognise homage to Rebote and the Clari in the input buffer and output section respectively.


Demos:
http://dl.dropbox.com/u/967492/Little%20Angel%20Demo.mp3
http://www.archive.org/details/LittleAngel-Pt2399-basedChorus





Version 2 incorporating anti-lock fix and noise reduction measures.


Version 3 incorporating anti-lock fix, noise reduction measures and Space/Warbler switch.


Version 4 incorporating all of the above, and a Chorus/Vibe switch.


295 comments:

  1. I've actually had a go with this one before, it failed and I've given up on anything PT2399 based. Now that I see a layout from you, I have to try it out!

    Thanks and I hope the lock up thing works (if I get that problem).

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  2. Yes I know PT2399s can be a nightmare but I bought 10 a while ago and so wanted to put together a few layouts that used them. I've already got a couple of more conventional BBD chorus pedals but I thought this sounded great and it'll make a nice alternative without having to run the risk of getting stung on expensive and hard to find MN3xxx ICs. I'm keeping my fingers crossed for this one.

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  3. What's D1 ? Do Speed 1 and Depth 1 go to ground ?

    ReplyDelete
  4. Doh, missed that one didn't I :o)
    It's a 1N4148 or 1N914, whichever you have on hand.

    Speed 1 and Depth 1 aren't connected in the schematic. If you really wanted to you could link them to Speed 2 and Depth 2, but it will still work wired like a rheostat.

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    Replies
    1. Thanks! I'm currently working on it. Even if it doesn't lock up, is it okay to use the little board? I'm kinda expecting it to lock so I just wired it up anyways. I'll be testing the layout in maybe 30 mins. Will let you know how it goes.

      It's not verified yet, is it?

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    2. No it's not verified, I only did the layout last night. You're fine using the daughterboard no matter whether it locks up or not.

      Delete
    3. Verified! It works perfectly for me (with the daughterborad, don't know without it). I went through all my PT2399 and only 2 didn't work.

      Thank you for finally letting me finish the Little Angel Chorus and restoring my faith in the PT2399 chip hah!

      Delete
  5. Top man! That's got to be one of the quickest layouts to verifications ever! :o) Excellent mate, thanks for your efforts.

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  6. Ooh and send me some pics please, it'll be nice to add them to my collection! :o)

    ReplyDelete
    Replies
    1. Will tomorrow, gotta get some sleep!

      Delete
  7. Incidentally, if anyone is wondering why I put the 1n caps two columns to the right of the 10n caps rather than a straight line up the side of the PT2399, it's simply because it will allow you to use box caps neatly in the spaces provided. Bend one leg back then bend it back out to give you an approximate 2.5mm pitch. Box caps are great for that and it keeps everything looking neat.

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  8. I'm trying the circuit out again now when I can have the amp a little louder. It's a fairly noisy circuit and I can hear the oscillation when I'm not playing anything. Don't know if that has anything to do with the fact that I haven't housed it yet in an enclosure.

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    Replies
    1. I've just been having a look through all the threads about it, and have included a V2 layout above which includes the anti-lock fix and noise reduction measures. This covers the noise reduction changes I've made and so you could maybe add these into your board:

      1) 1n cap between PT2399 pins 15 & 16 changed to 3n3. May be slightly darker but should reduce hiss (maybe socket that so you can experiment)

      2) 10K resistor between IC2 pin 3 and 9V

      3) 10K resistor between IC2 pin 3 and ground

      4) 10u cap between IC2 pin 3 and ground

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    2. Oh and a 100nF cap between regulator output and ground, a 100nF cap between regulator output and 9V.

      Delete
  9. Great layout. But I want to add a mix/blend knob in the ver 4 layout. Can you please give some suggestions on how to do it?

    ReplyDelete
    Replies
    1. To add a mix/blend pot, you'd need to remove the 100n cap at the output (the smaller one below the 10u cap) and add another below the other 100n output cap underneath IC2. Something like this:

      http://i76.photobucket.com/albums/j6/IvIark_2006/DIY/LittleAngelblendpot.png

      With an additional cut between the new cap's leads. Then Blend 2 would go to the output. So the pot will blend between the modulated PT2399 output and the dry signal coming from the NE5532.

      Or if you wanted the dry signal always present (the Chorus/Vibe switch will still be able to remove it completely if you want) then you could go this way instead:

      http://i76.photobucket.com/albums/j6/IvIark_2006/DIY/LittleAngelblendpot2.png

      Blend 2 would go to the output, Blend 1 to ground.

      These haven't been tested and I don't know how they might affect the output volume but they're definitely worth a try. It would be easy enough to change it back if necessary, or even add an additional gain stage and maybe an overall volume control, but that would mean a bigger layout or a small addon daughterboard of some description.

      Delete
    2. Awesome man......Thanks a ton..... God Bless u....

      Delete
  10. Hi Mark,

    I finished building and boxing up version 4 so it's verified. Sad thing is it's too noisy to be usable for anything besides demoing a PT2399 chorus effect :(
    Thats really a heartbreaking cause I love the way it sounds. I can't imagine how noisy it was before introducing these NR measures..

    ReplyDelete
    Replies
    1. Have you tried another PT2399 just in case? Some of them are noisier than others. Another couple of things to try, the 10u cap from IC2 pin 3 to pin 4 can be increased to 100u, as can the 47u cap between IC1 pin 1 and ground. That triangle of electrolytics around that area are all filtering supplies and so you could make them all 100u or even higher (220u maybe?) to see if that helps quieten things down. If you like the way it sounds then it's worth experimenting.

      Delete
    2. Thanks man, I will try your suggestions once I recover my enthusiasm.. Meanwhile I cheer myself with some Attiny programming.
      Regarding PT2399 ICs: I tried three, two were approx. the same noise level, the third one did not work at all :(

      Delete
  11. This comment has been removed by the author.

    ReplyDelete
    Replies
    1. Ha ha, I was just going to say "wrong site"! :o)

      Delete
  12. hi, I have completed wiring up V4, and am not getting an effect. I wired the input and output straight to the jacks to test it, and all I get is a bypassed signal with a tiny static clicking in the background. When
    i switch the chorus/vibe switch to the terminals without the resistor, it cuts the signal. What am I doing wrong?!?

    ReplyDelete
    Replies
    1. PT2399s can be temperamental sods, post the voltages of all the IC pins and that could give us a clue.

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    2. Incidentally, I used to work with someone called Mike Joyce. You don't work for a large German electronics company do you? :o)

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    3. now everything seems to be working alright, except for the clicking is still there, and its REALLY REALLY LOUD.

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    4. haha no, im a programmer in the US

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    5. The clicking will be the oscillator in the PT2399, but some of the noise reduction measures should have tamed that much more than the original V1 layout. Did you socket the PT2399? Still check the pin voltages because that really would make some issues obvious. Importantly you should have pretty much bang on 5V at pin 1 of the PT2399.

      Delete
    6. yeah it's socketed. what would cause it to be so loud? one guitar with an emg was more overdrive that chorus, a strat wasnt bad

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    7. pin 1 is at 4.86v. ill have the rest in a minute

      Delete
    8. 1) 4.90
      2) 2.44
      3) 0
      4) 0
      5) 4.90
      6) .36
      7) 0
      8) 0 pulsed +/- 0 though
      9) 2.45
      10) 2.45
      11) 2.45
      12) 2.45
      13) 2.45
      14) 2.45
      15) 2.45
      16) 2.45

      Delete
    9. The voltages don't look bad, although I would probably expect to see something on pins 7 and 8. Did you put both cuts under the 2K2?

      What are the voltages of IC2?

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    10. yeah both cuts are there. IC2
      1) 4.91
      2) 4.48
      3) 0
      4) 0
      5) 2.93-3.02
      6) 3.27-3.32
      7) 0
      8) 9.46

      Delete
    11. You should be getting very close to half the supply voltage (pin 8 reading) on pin 3, so I would expect to see a figure of around 4.7V on there. If it's 0V then there is a problem with either you soldering (maybe a cold joint?) or the 10K resistors going to the 9V and ground row.

      That's definitely wrong so you need to be looking for any issues around there, possibly an unwanted bridge between the pin 3 and 4 rows which would basically dump all the voltage to ground. Just look closely for any stray solder or burrs going between those two rows.

      Delete
  13. have i told you lately that i love you? It was a tiny fleck of copper shorting the tracks between ic2 pin 3 and 4. the guitar with the emg is still distorting it a bit, but a lot of that will most likely be fixed once its boxed up. and its sounding AWESOME now. thank you so much!

    ReplyDelete
    Replies
    1. Nice one, I like it when they're painless like that! :o)

      EMGs or any sort of higher output pickup can put some grit on many chorus or modulation pedals so that's totally normal. I had a Jacques Meistersinger which I loved and was perfect with a Strat, but I could always hear some breakup with a Les Paul.

      What do you think of the Chorus/Vibe and Space switch by the way, are they both useful? I haven't built this yet so haven't had chance to play.

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    2. the chorus/vibe makes a world of difference side to side. the space switch makes a subtle difference, but its definitely very useful as well. I'm personally a fan of deeper choruses, but this has so many tones with just 2 knobs and 2 switches, I'm absolutely a fan. Think a Duncan Alnico 2 pro will cause it to break up a lot?

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    3. I've got one of those in my "Slash" guitar :o) No I don't think it will, they're great pickups but aren't high output.

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    4. excellent. Now to build the Causality Phaser. I'll have to keep an eye on my cuts, make sure theres no shorts again :)

      Delete
  14. Built this late last night, and noticed couple of things..

    Went through my batch of PT2399s and couple didn't work at all, but rest gave about same ammount of noise - not enough to call it a problem, but there is some. That's not a bad thing though. It gives certain nice lofi feeling to some settings. Circuit still sounds very good. If one would need completely noise free version of this, i suggest that the one gets buttloads of PT2399s.. :)

    Other thing was with the pots. B470K as depth doesn't seem to do anything from 0% to about 45% and speed has similar problems. Since these are wired as rheostats, i'm going to swap that depth pot with B250K and see if that gives me better control. I thought about swapping that B100K for B50K and adding 18K or 22K resistor in series, but blah.. Don't think i can bother with that.

    If that B250K works well enough, i'll box this right away...
    +m

    ReplyDelete
    Replies
    1. http://mirosol.kapsi.fi/varasto/boxes/angelv4.jpeg

      Here we go. I might swap the pots for even smaller ones, but it's ok for now with B250K for depth. Don't know why it acts like that with original values, but it's still not broken, so why fix it any further..

      Knifing the texts wasn't as fun as i thought and it didn't came out as pretty as i wanted.. Guess it's ok.
      +m

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    2. Thanks for the info and the pic mate

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  15. Hi IvIark, i have a problem with the version 4.! :( could you please check my voltages.?

    1) 4.90
    2) 2.44
    3) 0
    4) 0
    5) 4.90
    6) .36
    7) 4.53
    8) 4.53
    9) 0.13
    10) 4.21
    11) 4.21
    12) 0.13
    13) 2.48
    14) 4.80
    15) ~~~~
    16) 2.50 - 2.60

    and

    1) 4.91
    2) 4.48
    3) 4.7
    4) 0
    5) 2.93-3.02
    6) 3.27-3.32
    7) 2.63-3.18
    8) 9.46

    I have big trouble debugging this .. i get in the output the input signal as is.. :/ could you suggest anything.??

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  16. i built the v4 and...no sound....also the 78L05 is overheated....

    1)4.98
    2)2.50
    3)0
    4)0
    5)4.98
    6)0.64
    7)4.59
    8)4.59
    9)4.80
    10)0.53
    11)0.53
    12)4.77
    13)2.49
    14)0.23
    15)2.49
    16)2.49

    ic2

    1)8.90
    2)7.56
    3)7.41
    4)8.13
    5)7.49
    6)7.59
    7)7.87
    8)9.41

    ReplyDelete
    Replies
    1. Mark is away until the week end ;o)

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  17. hey Mark, when you get back, is there any reason this would be noisier when i box it up? Did i just cross something somehow?

    ReplyDelete
    Replies
    1. You could double check the outboard wiring. Especially switch and pots. One of those might be leaking to the ground. Build this myself last week, and it works properly...
      +m

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  18. The outboard wiring works fine, I triple checked that. The effect itself is much louder than bypassed signal, and has a clicking noise dependent on the position of the speed knob. Could I have a wonky PT2399?

    ReplyDelete
    Replies
    1. That is one possibility, but since it worked fine until boxing..

      How did you attached the board to the box? Could there be a short under the board, between the board and something else?
      +m

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    2. the board isnt actually attached to anything, and when i tested it prior to boxing it, i hardwired the input and output direct to the jacks.

      Delete
    3. Could it be touching something? Are you using 3PDT stomp switch with basic true bypass scheme? Could the switch be damaged?
      +m

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    4. the switch is brand new, its functioning fine. I notice a bit of clipping and distortion when using a guitar with humbuckers through this circuit, which leads me to believe its something on the board

      Delete
  19. Replies
    1. Without having the unit in front of us it's hard to comment Mike. If you're getting noise from it now that wasn't there before it was boxed, then it suggests a problem with the offboard wiring or soldering. Check for continuity between all points of ground, board, DC socket, input and output sockets etc, and make sure you haven't created a ground loop anywhere.

      If anything boxing up an effect should make it less noisy because of the shielding the box provides.

      Delete
    2. It's been documented that faulty or wrongly connected PT2399 can cause weird sounding distortion/od - i have that sound in my Blencowe build..

      But if it really was working fine before it went in to the box, the problem must be with the outboard wiring.
      +m

      Delete
  20. well, it was distorting a bit before boxing. the clicking noise was there previously as well, i had just hoped it would go away when boxed. I know the wiring works, but
    I can double check it. I'll do that when I get home from work, as well as connecting a ground wire from input to output. If that doesnt help, I'll order a few more pt2399's and mix and match until I find one thats cool.

    ReplyDelete
  21. mike if you used led for on-off check the led maybe the problem its there....

    ReplyDelete
    Replies
    1. would that really affect it? i thought that was isolated?

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    2. I've built a pedal and the problem was the led, it was making a noise....check it!i say maybe not for sure!

      Delete
  22. so I pulled out the pt2399 in a fit of rage, and the damn clicking and distortion was still there!!! what could it possibly be?!?!? I know its not in the offboard wiring, or the LEDS, since it was doing this before either of those were hooked up. PLEASE HELP

    ReplyDelete
  23. another pt2399 or another ne5532?

    ReplyDelete
    Replies
    1. PT2399. They're notoriously temperamental in some circuits, in fact I'm pretty sure in one of my layouts using them someone said they tested 10 and only 2 worked perfectly. The first thing I'd always look at in this kind of build is the PT2399 or the regulator, but as you're getting close to 5V on pin 1 it looks like the regulator is doing its job.

      Delete
  24. I ordered more of each. Why would it still distort and click with the chip out though?

    ReplyDelete
    Replies
    1. Measure voltages on the regulator. Use magnifying glass and a knife to go through all the gaps in the strips. My best guess, with those symptoms, would be nearly invisible solder bridge shorting something out.
      +m

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    2. ok, i'm at work now, so as soon as i get home ill do that. it should be 9v on the in, 5v on the out, and whatever on the ground, right?

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    3. Yes, 0V on all points of ground and make sure there is continuity beween them all

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  25. ground is good, as is the 78L05

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  26. i'm seriously baffled. i'll try cleaning between the traces tonight but i'm out of ideas after that

    ReplyDelete
    Replies
    1. The problem we have Mike is that when we know a layout is verified, it means that a problem has to be down to one of two things, either an error in the build (including offboard wiring) or (a) faulty component(s). LFO noise where it shouldn't be hints at a grounding problem or a tiny unwanted bridge in the wrong place, but really only the person with the board in front of him is in a position to closely check those things over.

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    2. oh I know, I'm certainly not implying that the layout is incorrect. Ive put everything in as per the diagram, I just have no clue as to what to look for when correcting the problem. I'll try and clean up the back of the board and see if that helps. since the distortion and ticking were present before I had it wired up to the switch, I have to believe that the problem is somewhere on the board. sorry if I made it seem that I was questioning the layout

      Delete
    3. I didn't think you were questioning the layout, it's just there is only so much we can do over the internet, and so when we know the layout is correct there is only two possibilities as to why it doesn't work. And only the person sat in front of the board is in a position to check the build, offboard wiring or the components.

      If you want email me a front and back pic and I'll see if anything stands out, but failing that, and assuming you're totally happy with the offboard and build, then you're going to have to look at identifying any faulty components.

      Delete
    4. Oh and incidentally, I know exactly how frustrating it can be. Sometimes it's nice to put a problem build to one side, make something else, and come back to the problem build later. Unlike Vince who would have thrown it in the bin by now (just kidding mate :o)

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    5. haha I hear you there. I'll check it again when I get home, as well as quadruple-checking the offboard. I really hope its just a sliver of something, as it was initially.

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    6. Hahaha!.. No no Mark, you're completely correct. The frustration eats away at me and I just can't leave it, Impatience is my downfall.If I REALLY want the effect, I'll just make it again.

      The Wampler plexi drive is STILL bugging me. I really want to make it again but after two attempts and the tone pot not working on both I fear the same, or I am doing something fundamentally wrong with that one.

      Delete
  27. Started to play with mine today just for fun.. I sticked my cheapo wall wart to it, and it sounded strange. No effect, just louder than bypass. Plus the vibe/chorus switch was mute on the other position. Checked basic stuff out, and noticed that the regulator gave out only 1,2V. Measured the wall wart, and it says 9,3V... Which shouldn't be enough to burn the regulator. Swapped it for a new one and switched that wall wart for a battery. Everything worked like a charm again.

    Couldn't believe that the adapter had burnt the regulator, so i tried with the wall adapter again - it burned the regulator right away. Swapped it for a fresh one again and it worked. Best not use that adapter with these regulators i guess.. But i don't thing that in normal circumstances PT2399 could ever draw more than that 100mA. I guess it seems like i have some ground leak in there somewhere. I could swap the regulator for 7805, which is rated 1A. But that's like using bigger fuses to prevent them from tripping...

    Are there any simple solutions to protect regulators?

    Then i played with it for a while. Suddenly it started to sound really crazy. Like a sitar on acid. And the controls stopped working right. My best guess is that whatever burnt the regulator might have done some damage to the PT2399 as well.

    I'll get some sleep, go to work and figure this out after that tomorrow. I'm pretty sure there is just something fairly simple i've missed. Does that space-sitar description sound like that locking issue the earlier revisions had?

    I'll try another chip and we'll see how it goes. This is the first time that something i've built started to act up later than on the building phase.

    Good night to you all.
    +m

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    Replies
    1. One thing is for sure, this layout has given the most entertainment and intrigue out of any of them! :o)

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    2. :D Just wait until someone verifies Causality... :)

      Rick Holt deserves a sorcerer's hat. Circuit is fairly simple, but there's still some dark magic going on in there.
      +m

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    3. Took this back on the desk tonight. Swapped 78L05 for heavy duty 7805A and tried a few different things to light it up again. F it. It worked good before i gave it the wall wart. But after hours of "repairing" it, i don't think i'm going to get it working again. So. One more circuit to the jar of horrors.

      (http://mirosol.kapsi.fi/varasto/boxes_other/JarOfHorrors.jpg - It filled to that point quite easily at the beginning of my addiction. Nowadays mainly "tried and didn't like it enough to even mod it" circuits end up in there :))

      Oh well. I've built over 20 without problems after this one, so i guess it's more than ok to have one complete failure in every 25 builds :)

      If i'm going to rebuild this or any other 5V circuit, i'm going to use only those 7805As.
      +m

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  28. I'm going to try and rewire this when I get home. If that doesnt work, then I'll post pics to see if I screwed anything up royally.

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  29. I've replaced the electrolytic caps that were installed questionably, and cleaned inbetween the tracks. NOTHING IS CHANGING! I've changed both ICs several times. no change. I'm really out of ideas

    ReplyDelete
    Replies
    1. If you take it out of the box now, does it work? How have you got the actual board mounted? There's no chance that somewhere on the track side of the board is touching metal somewhere is there, maybe creating a bridge or grounding something it shouldn't?

      Delete
    2. its in the box, but i dont have it mounted to anything. and theres no back on the box yet, so it's 100% free. could this be distorting simply because im putting it into a bass amp? or is there maybe a way to wire in a volume knob? or knock down the input signal? when i roll the guitar's volume down to about 6 or 7 it works great, but that damn ticking is still there.

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  30. so what should I do? Is there anything else I should look at?

    ReplyDelete
    Replies
    1. How about the voltages? Do you get 9V/0V/5V at the regulator?

      At that point i personally would rebuild the board. And measure all the components before soldering anything. Since you've been through all the usual suspects, it's likely that there is some bad component. Did you use sockets for regulator, transistor and the ICs?
      +m

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  31. Yes on the voltages, and yes on the sockets

    ReplyDelete
    Replies
    1. You could post front and back pics in high resolution...

      ..Or just rebuild it.
      +m

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    2. when I get home from work I'll throw some pictures up. I'm sure its something stupid on my end

      Delete
  32. http://s880.photobucket.com/albums/ac1/maniac_mikej/?action=view&current=2012-05-23202011.jpg&newest=1
    http://s880.photobucket.com/albums/ac1/maniac_mikej/?action=view&current=2012-06-12191436.jpg&newest=1
    http://s880.photobucket.com/albums/ac1/maniac_mikej/?action=view&current=2012-06-12191800.jpg&newest=1

    The only difference between the first one and the third one is I replaced most of the tantalum capacitors with regular electrolytic caps.

    ReplyDelete
    Replies
    1. Guys sorry to be a pain but I really need to have this figured out by sunday

      Delete
  33. said the hell with it and reverted back to V1. kept the c/v switch active, but the space warbler one eluded me. works. verified. thank you all! anybody know how i'd hook up the space/warbler switch on v1? i didnt make the antilock daughterboard. I'll cross that road when I get to it.

    ReplyDelete
    Replies
    1. The Space/Warbler switch comes off the base of the anti lock transistor, so if you haven't included it you won't be able to have the switch. Check out the main thread on DIYStompBoxes:

      http://www.diystompboxes.com/smfforum/index.php?topic=86297.0

      You may find a few other mods that interest you

      Delete
    2. ok, so if i just run the wire from the base of the transistor on the daughterboard, it'll be business as usual?

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    3. Yes, the daughterboard is just an extension of the main board so the S/W switch connects in exactly the same way

      Delete
  34. I finally got around to building this. The most complicated effect I've built so far so I have to say I was actually a little surprised when it worked as I fired it up for the first time! Just wanted your thoughts on one aspect though.

    When I play through it with neither the s/w nor c/v switch engaged, it sounds almost like a slapback delay. Kind of like if you have the regen knob turned past the middle point on a delay pedal so that you hear the delayed note louder than and behind the note you just played ( except that you don't hear the first note - its all just a little behind what you've just played ). It happens regardless of speed or depth setting. I really only notice it when I play a string of single notes - it's fast enough so that I don't really notice it too bad when I am playing an arpeggio. Very noticeable on single notes though. It almost has that "pop" too of a compressor ( I think that is just the delay fooling me ).

    Is this normal for this unit? Anyone else experience this? I tested all the components before soldering and there were two components that were a little off - the 1n cap measured 1.26nf ( I measured all 20 that I had ordered and they were all off the very same amount ), and the 220k resistors were right around 200k each. I used them anyway since they weren't grossly off, but I wonder if these components may account for the slapback because of where they are in the circuit. I don't want to unsolder and replace if these are not the cause. I haven't swapped out the pt2399 chip yet ( I have read all the comments here and elsewhere about the inconsistency of these so I ordered several extras ) but will depending on what I hear back from here.

    The only other thing worth mentioning is that the slapback sound doesn't happen in the vibe mode. I would just use that mode but I like the slightly darker tone of the normal mode.

    Very nice sounding unit. Sounds better than my old boss chorus. Ijust want to fix this little imperfection if possible.

    Thanks

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    Replies
    1. Yes it may well be the 200K resistors that is causing the problem. They're part of the speed circuit and as this creates a chorus effect by creating a very short modulated delay and adding it to the dry signal, those resistors will almost certainly affect the delay time. You won't get it in vibe mode because that cuts the dry signal completely and so any slight latency in the vibe effect would be less noticible.

      Delete
  35. Well, I'm glad that it can be attributed to one of the components that I mentioned. Hated to leave such a lengthy post but it looks like it helped. Just need to detach a few wires ( all boxed up )and get those swapped out for the correct value.

    Thanks for the prognosis! I'll post back with results after I get this back together.

    ReplyDelete
  36. Swapped in the 220k resistors. Still the same slapback sort of sound. Swapped the 2399 for another - same. I didn't replace the 1n cap that had measured 1.27n. If you think that is not really a part of the issue, I'll probably just build another - I like the sound of it if I can get rid of the little slapback-ish sound. Might be easier than chasing something odd down. I appreciate your help and all the layouts here!

    Thanks

    ReplyDelete
  37. hi Mark,
    i built your layout of number 4, it's working, but i swear to god it's on an overdose of LSD or special k or something.
    when it works, it is AMAZING...totally in love with it.

    but it locks up on every power up, despite the "fix"...i read rick's thread on DIYstompboxes, and tried merlin b's fixes, changed the 68k resistor to 220k (which helped a little) and even tried lifting the 47r resisor and replacing it with an led from e of the 3904....no dice at all on that one.

    i tried 12 different 2399's, one was bad. period...the rest all worked, some sound great, some not so great...

    but here's the thing...if i take the bottom rail's ground as shown on your vero, and intermittently connect it to ground, usually on the 4th or 5th connection, suddenly the chorus kicks in. since boxing it, i just plug/unplug the input jack...again, always 4-5 times, and then the effect comes in, and will at that point work until i power down.

    i've checked voltages, they all seem good, and indeed, the effect works great once it's on...but until i f with the ground a few times, all i get is buffered dry, no effect (if i put it on vibe, it kills everything, so i know it's something to do with the wet part of the circuit).

    nothing changes when it's working or not voltage wise, so man, i am stumped!!!

    i've checked and rechecked, used a jeweler's loupe to check the circuit, everything seems right to my newb self..

    so...any ideas? anybody else run into this issue or something like it?

    btw...i discovered if you get a lot of noise when the effect is on, try replacing the 7805...if the regulator is bad, you get a ton of background noise, including whooshing sounds and an insane amount of lfo ticking. changing the reg fixed that...hopefully it may help someone else.
    thanks bro!
    peace
    pinkjimiphoton

    ReplyDelete
    Replies
    1. Hi Jimi, the only time I've come across a frequent lockup problem like yours was with my first layout of the Deep Blue Delay when I didn't have pin 3 of the PT2399 grounded. That behaved in exactly the same way and locked up everytime but as soon as the guy who built it grounded pin 3 the problem never came back. Are you sure you don't have a cold joint on that or any of the other ground connections? Are you getting constant continuity between all points of ground?

      Delete
    2. hi mark,
      i will double check on that...pins 3 and 4 are both jumpered together, and connected to the jumper..i wonder if the solder joint to pin 3 under the ic socket might have gone bad? those two connections are the only ones i can't get at.. great tip, i will check it in a couple minutes, worst case, i'll jumper it from pin to pin of the 2399 and report back.
      it DOES seem to make sense, as that's probably the only place i haven't checked and re-checked!! thanks bro!!
      be back shortly, hopefully with positive results!

      jimi

      Delete
  38. hi mark,
    i checked again, and took voltage readings...and discovered it's something to do with pin 2 of the 2399...as soon as i touch that pin with my meter lead, the circuit goes dead. if i hit it again, the circuit fires up again!!

    the grounds are solid, checked, picked at 'em with a dentist pick, they're good. looking at it, there's not much of anything connected to pin 2 really before it hits the speed and depth pots. frustrating!
    i took two sets of voltage readings...btw, subbed a tl082 for the 5532... but i wouldn't think it should matter...

    anyways, the voltage on the dual oa is consistent:
    power supply from wart = 9.47v

    1 4.75
    2 4.44
    3 4.73
    4 0.00
    5 2.93
    6 3.26
    7 3.09
    8 9.48

    the 2399, when working, appears to be as follows..i checked all the pins other than pin 2 while it's working, as soon as i hit pin 2 it's dead. the pin 2 voltage is what it reads when it dies..
    1 4.83
    2 2.37
    3 0.00
    4 0.00
    5 modulating, around 1 volt
    6 same
    7 same
    8 .85
    9 2.39
    10 2.40
    11 2.40
    12 2.41
    13 2.40
    14 2.37
    15 2.40
    16 2.40

    as soon as i touch pin 2, i get
    1 4.83
    2 2.37
    3 0.00
    4 0.00
    5 4.97 (an internal short in the 99? there's nothing connected to it!!)
    6 .48
    7-16 0.00 volts.

    something is up...gonna try and look at the internal diagram of the 2399.

    so anyways, now i'm wondering if i should just add a mini momentary n.o. switch between pin 2 and ground to "reboot" it.

    stumped brother, stumped!!
    ;)

    ReplyDelete
    Replies
    1. The datasheet always seems to show a 47u cap between pin 2 and ground (pin3). I've included that when doing delay layouts but not on this. I don't know if a filter on the reference would help, but it may be worth a try.

      Delete
  39. i'm on it, let's see if it does anything!! ;)

    ReplyDelete
  40. ok, tried the 47u...actually 100u...no diff, other than not being able to jumpstart the 2399!!

    weird!!! so i took it back out...100u there did seem to "smooth" the modulation slightly tho.

    ReplyDelete
  41. dumb question, but when i built this, i subbed a 1n4001 for the diode instead of a 914...could that be what's making this thing so weird do you think?
    maybe not enough leakage for the transitor to turn on or something?

    thanks mark...still trying to figure it out!!

    ReplyDelete
    Replies
    1. I would doubt it, I suspect either diode would work fine

      Delete
  42. made a little progress, now i only have to re-plug the input once and it kicks on.

    really weird. i re-soldered everything on the board, but still can't seem to figure it out.

    sux, cuz this thing sounds excellent when it works! ;)

    ReplyDelete
  43. Built this and I'm having the exact same scenario as Microsoft had with the exception that I'm using an ultra clean power supply measuring a constant 8.98v. I'm getting the same crazy sounds and the vibe switch mutes the signal, pots doing nothing. Plug it into a battery and it works exactly as it should. Battery measures 8.77v, I use an I/O box ala the beavis board with a sag pot, brought the power supply down to 8.77v to match the battery but still the same. This is some weird freaky shit.

    ReplyDelete
  44. Damn that iPad predictive text, for Microsoft read mirosol :-)

    ReplyDelete
    Replies
    1. :D

      I was thinking about placing 1N5817 or 1N4001 in series with 9v wire, but i just scrapped the whole thing :) That could be good thing to try..
      +m

      Delete
    2. Very weird indeed. Maybe something like a 100R current limiting resistor in series with the supply?!

      Delete
    3. ..or maybe both. Maybe even 9,1 zener. And i can't see any harm in using heavier regulator like 7805A. With those three.. if it doesn't work then...

      Only difference in wall wart dc and battery are ripples and base current. If i was to rebuild this, i would probably use all the above methods for calming the power source.
      +m

      Delete
    4. For the ripple maybe upping the filter cap to 220u may do the trick? Still very strange.

      Delete
  45. i've given up on the damn thing. it works, absolutely stellar, once it works. but i've gotta plug it in a couple times to get it to work, then it will work til power down, at which point i have to re-plug again. a pain in the ass.

    i'm suspecting the latch up comes from something in the chip frying on power up.

    but no idea how, or why...

    ReplyDelete
    Replies
    1. Jimi did you have problems with power supply and battery?

      Delete
  46. hi mark,
    nope, never tried a battery in it.. if it won't run on ac, it has no place on my pedalboard so i don't usually put bat clips in if it's for me...only if someone asks me specifically to add one do i put one in. i could try it, see if it makes a difference.

    all i know is every pt2399 circuit i've tried has been on acid.

    ReplyDelete
  47. [Version 4]
    Could I trouble someone to tell me what the difference in the orange and red caps on the drawing is? Also, what is D1? Rectifier? Spec?
    Thanks

    ReplyDelete
    Replies
    1. Comments suggest D1 as 1N4001. Still curious about orange/red caps.

      Delete
    2. I use the burgundy cap symbol most of the time because it matches the Panasonic caps I usually use. I use the orange cap symbol which is the layout softwares ceramic symbol when there is only a 2.5mm pitch required between the cap leads. If I use the same Panasonic symbol here then you won't be able to read the value properly because the text will be obscured by the blue dots which show where the leads are soldered. But if you have polyester caps that are suitable for a 2.5mm pitch then just use them and ignore the colour of the symbol used in the layout. I will use ceramic multilayer caps sometimes if space is an issue but I avoid normal ceramic for most things except maybe some fuzz pedals.

      Delete
  48. I need to do something different that 470k on the depth. Is there any value I can swap it out for? 500k?

    ReplyDelete
  49. |V|ark or microsol, another question about the depth pot on this one:

    Should the wiring look like the photo in the link or should there be a hookup between the DPDT and the PCB?

    http://i1270.photobucket.com/albums/jj611/the_8lack_hat/JlAB/45850288.jpg

    ReplyDelete
    Replies
    1. Yes that's right for one side of the switch, and the Space Sw wire shown on the board goes to the Space Sw lug of the switch.

      Delete
  50. Built it and got problems... :-( I've barely got any effect and there seems to be a slight distortionsound in the background, alongside the original signal. Any ideas?

    Tnx

    ReplyDelete
    Replies
    1. What voltages are you getting at the IC pins and have you tried any other PT2399s? This does seem to be the most temperamental layout on the site with plenty of mixed results.

      Delete
  51. try more 2399's. as a chip, they sound great when they work, which seems to be rare.

    when they DO work, they sound outstanding...i've built Mark's layout, and a rebote, guitarpcb's d'lay, and anchovie's one chip chorus, and NONE of them are sure to work.

    try repeated power up cycles, and see if you get effect working...it sounds to me like the infamous "lockup" these chips do. sometimes powering them up with the delay time pegged helps, sometimes not.

    termperamental sob's, for sure!!

    keep at it tho, you'll get it...voltages will tell a LOT.

    ReplyDelete
  52. Replies
    1. Tnx for your suggestions, Pinkster, but alas... I've tried 5 different PT2399's and also tried the repeated power-up cycles, like you suggested. No change... I think I must have something wrong in my build.

      Mark, I've measured all the voltages at the pins. They sum up to this:
      The PT2399:
      1: 4.94
      2: 2.43
      3: 0
      4: 0
      5: 0
      6: 0.63
      7: 0.88
      8: 0.95
      9: 0
      10 to 16: all 2.44 each

      As for the NE5532:
      1: 3.91
      2: 3.26
      3: 3.63
      4: 0
      5: 2.26
      6: 2.54
      7: modulating between 2.40 and 2.53 (???)
      8: 7.19

      Any suggestions would be very helpfull; tnx!

      Delete
  53. jeroen, if memory serves, pin 9 of the 2399 should be reading b+

    check for solder bridges, etc around there, and use the continuity function of your DMM to make sure there's actually a connection.

    an audio probe can help too...

    hmmm, just looked at my previous post...your voltages look like mine did.

    sounds like the 2399 is locking up.

    just for sh*ts and giggles, try shorting pins 2 and 3 and see if it suddenly works for a split second...if so, it's definitely the infamous lockup.

    ReplyDelete
    Replies
    1. Hi Pinkster, tnx for your help. Shorted pins 2 + 3, but no change.

      What did you mean by: pin 9 should be reading b+? What does the b+ stand for?

      Delete
  54. b+ is an archaic term from the days of tubes/valves, it meant battery positive.

    if you look thru my posts earlier in this thread (well, on this page) you'll see the voltages i got, and pin 9 had a voltage going to it.

    fwiw, i have never sorted the problem out still, i love the effect but can't use it cuz the damn 2399 locks up 99 out of 100 times at power up, and there's no way to be sure i can get it to work.

    and if it IS working, as soon as i try to take a measurement with the meter, it dies...and i have to power on and off, again, a whole bunch of times.

    try this, too...which seemed to work for me...take a jumper from the bottom rail, and quickly brush it against ground. on mine, that would make the circuit work, every time.

    i tried putting a normally open momentary switch in, figuring i could use that to make it work, but it didn't.

    pt2399's are bloody maddening chips, mate...

    ReplyDelete
    Replies
    1. Anothing I've noticed is that everybody seems to get a reading op pin 5, but I don't. Most posts get up to about 5 volts, but mine is dead.
      Does that spring any ideas?

      Delete
  55. 7.19V on pin 8 of the NE5532 is very low, are you using a battery? If you really are only getting just over 7V from your power source then you're very close to the minimum voltage for the regulator which can cause these sort of problems.

    ReplyDelete
  56. Hi Mark, I wàs using a battry. Now I attached an adapter instead and it raises the tiny amount of effect just by a little bit. But still nothing like a lushious chorus; just a slight 'jibber'.
    What did you think of the readings on the PT2399?

    ReplyDelete
    Replies
    1. Have any of the voltages changed with the higher supply? As it stands pins 5 and 9 aren't right. In Rick's original verified build he had 5 at 2.75V and 9 at the same voltages as 10 - 16 and so around 2.4V. Try re-clearing out the track cuts just in case some burrs have fallen in any of them which could be causing a bridge.

      Delete
    2. All the values on the NE5532 are higher. The values on the PT2399 are more or less the same, with the exeption of pin 9, which now also reads 2.45.

      Okay, so something wrong round pin 5, I guess, eh?

      Delete
    3. ...but 5 is 'clock', isn't it? It's not connected , so where would it get it's volts from? Shpuld I be looking at another pin...?

      Delete
    4. Hang on: the 2N3904 is connected in the shape as on the veroboard-layouts (v2, v3 and v4): a D-shape. But looking at its datasheet it should be in a C-shape, like most NPN's.

      Is the 2N3904 drawn upside-down on the layouts or am I saying something very stupid here...? And: could this be the problem?

      Delete
    5. Pin 5 is the clock output so it not being connected to anything wouldn't stop there being a voltage reading there. For whatever transistor you've used the pinout should be C, B, E from top to bottom so yes if the 2N3904's need rotating to match that pinout then that must be done.

      Delete
    6. Okay, changed the transistor round, got rid of the 2 switches, checked all the parts, resoldered all the joints, cleaned all the inbetween-the-tracks and the track-cuts.

      I now have a very modest chorus with depth maxxed, so I ditched the depth-pot too. It works, but is not what I expected. Don't know what I did wrong here, but I give up...

      Incidentally, I lack knowaledge of electronics in a stunning way ;-) but have been able to build succesfully an odd 25 diy-fx (mostly tnx to your fantastic blogsite btw!) including the Noise Ensemble, the Clari(not), the Deep Blue Delay and the Crap-Fi Delay. These are all PT2399-builds, but I've never had any problems with them before. All previous problems were due to my own stupidity, which I considered to be a soothing and calming thought: just keep looking and checking and you will find where you f*cked up. Could this be the first build in which the failure isn't to blame on me? The world may be different from today on, but I'm still hoping it's my stupidity that did me in on this build.

      Signing out, tnx once again for all your help, Mark! And for your great blogsite.

      Delete
    7. If you read some of the threads about this you'll see that more people seem to have issues than straight successes, so you're definitely not alone. I suspect something is not quite right with the schematic we're all working from which is causing the inconsistency but I just don't know. I'll keep checking the threads and update the layout as and when I see any possible fixes.

      Delete
  57. Replies
    1. Excellent, glad you got it working ok

      Delete
  58. i think it's an issue with the 2399...i've had other pedals with that lock up if the delay time is at minumum...a dano "shift daddy" did the same thing to me a couple days ago (and has the famous 2399 background noise, too).
    rebote 1 did the same to me..maxing the delay time pot and rebooting fixes it every time. i'm wondering if maybe a useful mod would be a momentary no switch with a decent sized resistor across it to hold down at boot up of the pedal?
    glad to hear it's working, this is one beautiful effect, and a KILLER layout as always!

    ReplyDelete
  59. I read a lot of posts... but
    1) is there the schematic of noise reduction measures?
    2) I've the annoing LFO modulation in output when I'm not playing.
    These issue seems not solved.
    It's incredible I have the same in my Boss CE-2 clone, for that
    i decided to built the "little Angel" and I'm now ath the same point!!!

    ;(

    ReplyDelete
    Replies
    1. Which version did you build Franco?

      Delete
    2. This:
      http://www.diystompboxes.com/smfforum/index.php?topic=86297.msg726268#msg726268

      I've modified the inverting stage (op-amp) with a non inverting stage. I tested it without PT2399 and it works well and it hasn't noise.

      Delete
  60. you can raise the value of the caps 1n and 3.3n, but be careful it can get muddy.
    the modulation leakage could be wiring, use shielded cable and make sure all ground points are star grounded..

    ReplyDelete
    Replies
    1. So you haven't?
      No noise?

      I used star grounded and it isn't any crosstalk between cables;they're too short to create that and If I move them nothing change.

      Is there a schematic of 4 version posted here?

      Delete
    2. I don't have a schematic for the V4, just added the additional blocks as they were recommended on DIY Stompboxes.

      Delete
  61. i built mark's #4 layout, and used shielded cable and star grounded everything.. i get no noise whatsoever, tho the dang 2399 does lock up just enough to keep it off my live board.
    great layout, mark, btw, thank you!! i looked at this for months hoping someone would post a good layout, and this is a great one. ;)

    ReplyDelete
  62. I have a question, does the regulator require a heat sink? Mine seems to be heating up pretty badly, might have destroyed it.. Output of the regulator shows 8.5ish Volts.

    ReplyDelete
    Replies
    1. It sounds like it's faulty. You should be getting 5V out of the regulator and if you've supplied the PT2399 with 8.5V then you may well have damaged it. I've seen this and other PT2399 effects built with the TO220 style regulators and have never seen one with a heat sink so it should be ok.

      Delete
    2. Yup. I would also recommend TO220 regulators. I've burned so many TO92 devices with small shorts, that i'm never buying 100mA L7805s again. The 1A devices cost more, but they don't burn up so easily.
      +m

      Delete
    3. Cheers! I guess i'll head to the store tomorrow to get some new regulators. =D

      Delete
    4. Swapped out the regulator for a TO-220, changed the pt2399, got the effect to work! Thanks for all your help!

      I do notice a little noise, but only when i play a note, similar to the noise found in delay pedals that use the pt2399, is this an inherent issue with the pt2399 chips?

      Delete
    5. Yes the IC has a few faults that come up regularly with this kind of build, if you've got any more then do a few swaps and see if it does anything for the noise.

      Delete
    6. for real...buy 'em 20 at a time, and maybe ONE will be "right"... but that same one may not work at all in another circuit. keep trying tho, eventually ya will find one that works. ;)

      Delete
  63. Just fired it up and it sounds glorious. Has anyone been able to fit this with the two pots and two switches in a 1590B? Looks like it's going to be too close to get everything in there -- may have to move up to a 1590BB.

    ReplyDelete
  64. Well, I spoke too soon. After I boxed it up, it stopped working. I figured I caused a short by cramming it into a 1590B. So I took it out and could not get it working again. I could get signal but no effect. When I switched the chorus/vibrato to chorus, the signal would cut out completely.

    I put a new PT2399 in from another working circuit and nothing.

    After a lot more troubleshooting, I gave up and rebuilt the board -- twice!

    Everything was replaced -- ICs, switches, transistor, power regulator.

    Now I have clock sounds behind the clean signal but no chorus. And the chorus/vibrato still kills the signal completely when switched to chorus.

    This circuit has humbled me. Time to move on to another one.

    ReplyDelete
    Replies
    1. This is just one of those circuits that gives almost everyone a headache. Are you still getting dead on 5V at the PT2399 pin 1? Those regulators do seem as prone to problems as the PT2399s are.

      Delete
    2. Hi Mark.

      I'm getting 5.07 at Pin 1.

      IC1's all over the place. Pins 1, 2, 3, 6 and 7 are all oscillating. 4 and 5 are 0 and 8 is 9.1.

      As for the PT2399

      1 - 5.07
      2 - 2.4-ish (it moves around a bit)
      3 - .001
      4 - 0
      5 - 5.067
      6 - 2.06
      7 - .66 and falling
      8 - .684
      9 - 2.64-ish
      10 - 2.43
      11 - 2.4
      12 - 2.4
      13 - 2.4
      14 - 2.4
      15 - .092
      16 - 4.59

      I've replaced the regulator three times and IC1 and IC2 twice each.

      Delete
  65. looks like the pt chip is locking up.

    i know this sounds stupid, but try connecting/disconnecting the ground for the cct a couple times.

    my build locks up every time at power up. if i plug the input jack in several times in succession, it will work, every time.

    the fact that when you put it on chorus and get sound, and none on vibe (which i think is opposite what you report) makes sense, as if it's chorused, the dry signal should come thru, and in vibe mode, the dry signal is disconnected.

    pt2399's just are a pain in the ass.

    hang in there.

    ReplyDelete
    Replies
    1. Thanks for the help Pinkster. Unfortunately, no joy in Mudville. It's frustrating because I can hear the clock and know it's doing its thing -- turn up the speed and it gets faster, turn up the depth and it gets stronger.

      I would have abandoned this a long time ago but the darn thing sounded so damn good when it was working! =D

      Delete
  66. Just wanted to follow up. I ordered a new lot of PT2399s from Small Bear and..................we have chorus!

    Sounds fantastic in both chorus and vibrato mode. Everything from subtle chorus to almost green ringer-ish clanking vibrato.

    ReplyDelete
    Replies
    1. I think you've hit the nail on the head here mate. With the PT2399 it seems you really do get what you pay for.

      Delete
  67. amen that, mark....

    jason,

    YAY!!!!!!!!!!!!!!!!!!!!!!!!

    ReplyDelete
  68. hey jason, which kind of pt's did you get?

    i've seen a couple different scripts on 'em, just curious...the fancier looking ones seem to work best, i'm wondering if the others are bootleg?

    ReplyDelete
  69. These are the ones I got from Brian at Small Bear. I ordered 10 of them and all 10 work in the circuit!

    http://i203.photobucket.com/albums/aa227/axe_34/IMG_5671.jpg

    ReplyDelete
  70. thanks bud, i have some that look like that, too. some work. some don't.
    go figure!! ;)

    ReplyDelete
  71. Hi every one !
    I've nothing coming from the pedal :/ Just "hmmmmm"
    The IC2 is badly heated. I presume this is the problem. What did i do wrong ?

    ReplyDelete
    Replies
    1. Heating up any component usually points to a short somewhere it should not be. Knife the strip gaps and triple check every component placing plus links and cuts.

      You could measure the 7805 regulator voltages and if you don't have exactly 5V at the regulator output, then it's safe to assume that the regulator is done.
      +m

      Delete
    2. Hi, thanks for your help !
      So i knifed all the strip gaps. the IC2 isn't heating anymore. But the regulator still is and there's no way to hope it's not burned.
      I still have an other 7805 but I don't want it to burn again. So if the first one (the burned one) is heating up every time I plug the dc, does the new one will too ? Or is it heating juste because it's broken ?
      Many thanks, Georges

      Delete
  72. check the polarities of your electros. and watch for a solder bridge. sounds like you have/had a short somewhere in the power supply. the reg in there is probably shot. no way to really tell unless you replace it, which may cook the new one.
    it should get warm...is it hot, or smokin'? if it's just hot, and your voltages are good, it's probably safe to swap it out.
    if it's smokin hot, then there's something in the circuit that's hosed.
    you'll get it.

    ReplyDelete
    Replies
    1. Hi, thanks for your help :)
      No short, i knifed all gaps. There's no way i left a short somewhere.
      It's just getting warm, enough to burn myself by the way.
      I can't understand why, all the components are right in place. I checked with Photoshop !

      Delete
  73. How does one wire the LED in the Angel Chorus?

    I saw one on YouTube that seemed to show the LFO speed with LED.

    ReplyDelete
  74. hi mike,
    i think putting it from pi 1 of the opamp to ground may work.
    no guarantee
    ;)

    ReplyDelete
  75. This comment has been removed by the author.

    ReplyDelete
    Replies
    1. It's a voltage regulator so I is input (9V), G is ground and O is output (5V).

      Delete
    2. This comment has been removed by the author.

      Delete
  76. This comment has been removed by the author.

    ReplyDelete
    Replies
    1. The regulator is really borderline, the PT2399 doesn't like too much over 5V. There definitely seems to be a problem with the first channel of IC2 though, those voltages are very high. Are you sure the cut between pins 1 and 8 is complete and there are no little burrs in there or anything? Just re-cut that to make sure there is total separation between the two sides.

      Delete
    2. This comment has been removed by the author.

      Delete
    3. This comment has been removed by the author.

      Delete
    4. This comment has been removed by the author.

      Delete
    5. Not necessarily, a misplaced components or unwanted bridge could still cause the issues. Can you post a high res front and back pic of the board

      Delete
    6. This comment has been removed by the author.

      Delete
    7. This comment has been removed by the author.

      Delete
    8. This comment has been removed by the author.

      Delete
    9. Sorry I missed the pics being posted. I'm out tonight so will check them out tomorrow to see if I can spot anything

      Delete
    10. This comment has been removed by the author.

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      Delete
  77. Hi Mark,
    My pedal seems to work but I would like to double check the voltages.
    These are my readings with the pots full on:

    1 - 5.03
    2 - 2.5
    3 - 0
    4 - 0
    5 - 2.58
    6 - 0.66
    7 - 0.86
    8 - 0.87
    9 - 2.5
    10 - 2.5
    11 - 2.5
    12 - 2.5
    13 - 2.5
    14 - 2.5
    15 - 2.5
    16 - 2.5

    1 - 4.86
    2 - 4.6
    3 - 4.6
    4 - 0
    5 - 2.96
    6 - 3.06
    7 - bouncing from 3.1 to 3.17
    8 - 9.2

    and the voltage regulator
    I - 9.23
    G - 0
    O - 5.03

    Do they look right to you?

    Thanks

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    1. Yes they all look pretty good to me

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  78. Thanks, Mark.
    Wasn't sure what the values were supposed to be.

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  79. This comment has been removed by the author.

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  80. I've found this schematics:

    http://4.bp.blogspot.com/-3Rc3Hub8-gs/Ty8k_eFL2QI/AAAAAAAAA4k/q2ScJee6O80/s1600/LittleAngel-2.7.png

    Would this improve the effect?
    Would it be any louder?
    Where would you add the Chorus/Vibe switch?

    Thanks Again

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    Replies
    1. I don't really know whether it would be worth it, I'm not sure what mictester changed other than it being buffered bypass instead of 3PDT true bypass switching. In all honesty it would be fairly low down on my priorities though based on what I can see unless it offered more consistent results than the versions we already have. The best way to add a chorus/vibe switch would be to switch the 10K resistor at the output of the second opamp down, before the 0.1uF cap.

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