Friday, 11 April 2014

Little Angel Chorus - NYE Edition (AMZ modified)

Jack Orman's modifications to the Little Angel Chorus, which will hopefully help us get a bit more consistency with the builds.  Information about the mods and a schematic can be found on Jack's blog here:

Currently unverified but based on the verified original layout so should be good to go.


  1. They should rename this the Little Bastard Chorus.

    I gave it a try just now. I thought for certain that I had some J112s around, but alas, I must have dreamt it. So, I tried with with a 2N5457 after Googling around a bit and extrapolating. In the end it didn't help.

    In his article, Jack mentions settling on the J112 specifically, so I'm willing to believe the entire problem could be the transistor substitution.

    I recorded a sample of me fiddling with it and the sound I have out of it so far. I kept it to very simple strumming to best listen for the effect:

    If that link doesn't work, change the https to http, I just pasted the link SC gave me :)

    I really REALLY wanted to verify this one. When I first came on here, the Little Angel Chorus was big on my "to do" list, but I could never get it working quite right. I would often have to run a pair of tweezers underneath and short some of the PT2399 pins to get it to start working...

    It agitated the hell out of me.

    So when I saw this, I could only think "Old Nemesis, we meet again..."

    Anyway, when I get my hands on some J12s I'll report back, if someone else hasn't already managed to figure out this beast.

  2. Not sure what to say about this.

    I got the J112 transistors in, popped it in the board and fired it up. Whumpwhumpwhumpwhump.

    I cut power and replaced the PT2399 chip. Plugged power back in and it worked. Chorus. Warbly sea-sick chorus. I got my microphone out to record a clip with it and suddenly whumpwhumpsquealwhumpsquealumpwhusquealump...

    It starts whumping and oscillating. I turn it off. Back on, right back to squealwhumping. Switched the PT2399 out, now I just get a clean signal.

    I tried my old "magic trick" of shorting the pins. Whumpwhumpwhumpwhump.

    Replaced the PT2399 again. Whupwhmpwhuimpwhump. Replaced the J112. Whumpwhumpwhump. Replaced the 78L05. Whumpwhumpwhump.

    Shorted the pins. Clean signal only. Switch parts out a few more times with the same results... either clean signal, clean signal with whumping, modulated signal with whumping (rare), or squealing devil-pig whumping.

    I can touch the back of the vero with my finger and move it around and will occasionally find a spot that makes it do a soft whumpwhumpwhump, but that's it.

    The fact that I did have it working properly at one point would seem to indicate the circuit layout works... and the fact that some people have managed to build a working Little Angel Chorus (which makes me doubt my own sanity) means that there's a good chance I've simply horked things up. Either that or this is a PT2399 Executioner Circuit and I'm just killing all of my chips.

    I've double checked all of my tracks, cuts, etc. Later I'm going to use my dremel cutting wheel to go over all of the tracks and then hit the track cuts with a polishing brush that should be strong enough to get rid of any micro-hell-bridges without hurting anything else.

    If that doesn't do it, then fuck it. :)

    1. Ha ha!! Sorry to laugh mate, but your post sums up 90% of the posts we've had about this bloody chorus pedal! It seems that the consistency hasn't been improved :o)

      I bought a Caline chorus pedal just to rip apart and it turns out it's a Little Angel. So if they're mass producing them they must be confident that consistency isn't a problem. So as soon as I get chance I'll trace it and see exactly what they have done differently to the circuits we've used so far.

    2. Heh, by all means. :) I approached this one with a sense of humor after my previous attempts at the older layout. I had a good chuckle myself when the demon pig squealing sounds sent both of my cats diving out of the room.

  3. I found that there are a lot of dodgy chips (forged) about and they cause the clicking clock thing. Read about it on Dr Tweaks site and he has some chips that are tested and bought from the real manufacturer. Make sure your chips are from a reputable supplier as I got bad 'uns off Fleabay.

  4. This seems to work straight out of the box for me. I used J112 from ebay and PT2399 from Tayda.
    Definitely verified.
    Is there anyway to do the chorus/vibe and space/warble mods on this edition?

    1. Awesome, thanks for verifying!

      For the vibe mod remove the 10K resistor to the right of IC2 between the 100n and 10n cap and instead mount it horizontally across the top row with a cut inbetween the two leads. The for a vibe switch just use a SPST toggle, connect one lug to top right hand hole next to where you just mounted the 10K resistor, and the other lug needs to be connect to the far right hand hole on row 7 (the row the other end of the 10K used to connect.

      For the Space Warbler switch use a DPDT toggle with a 10u cap soldered between lugs 1 and 4, then take lug 2 to Depth 3 and 5 to the gate of the J112. I've really no idea if this will work though with this anti-lock fix so you'll have to try it and see, but that was how it was done with the original version. Maybe the easiest thing to do is just try it first by touching a 10u cap's leads between the two connection points and seeing what happens.

    2. Thanks, but i couldn't get either to work. I tried the vibe mod first and just got a clean signal. The space mod just locked it up, and resulted in clean signal. After disconnecting the power and removing then adding the j112, i got the chorus effect back. Anyway, i'm happy with the chorus.

    3. Hmm, that 10K definitely carries the dry signal to the output so that's weird. It should cut the dry completely just leaving you with the modulated output from the PT2399. The space warble was a bit more of a gamble I suppose with the anti lock being different from the one in the original.

  5. Built this last night and it worked! Used a 2n5457 in place of the j112. PT2399 was from tayda. I will have to do a bit of A/B testing with other videos to be sure it is working as designed but it is making a chorus sound. I did not have rev log pots so I just subbed a standard log pot in place till i get some ordered.

  6. Hey. Maybe not quite the place to ask this question. I bought the Caline version recently. Not a bad chorus, but all the good sound is squashed up in the far end of the rate pot. And I have the last quarter turn to adjust the rate. Could it be because they didn't bother to use a reverse log pot?

    1. Maybe. If you got a reverse log pot laying around in the correct value put it in and see what it does.

  7. Hi, I write here since the other post on "Little Angel" does not accept comments no more:

    Hi All.
    My effect doesn't sound :(
    I triple checked it and the first strange thing is that left ground (from the vero) is not 0.0V when tested with tester... seems that they are not connected... If I connect them I found:

    1. 4.97
    2. 2.46
    3. 0
    4. 0
    5. 4.97
    6. 0.31
    7. 0.02
    8. 4.54
    9. 4.66
    10. 0.41
    11. 2.47
    12. 2.51
    13. 2.48
    14. 4.82
    15. 2.47
    16. 2.47

    1. 4.60
    2. 4.58
    3. 4.56
    4. 0.00
    5. 0.56
    6. 0.98
    7. 1.30
    8. 9.15

    c. 0.10
    b. 0.67
    e. 0.00

    i. 9.15
    g. 0.00
    o, 4.97

    If I link or not the two grounds, nothing change, the effect doesn't sound

    Any help appreciated.

  8. F*CK THIS CHIP!! jesus... one more fail here too. every single one of these little angels has screwed up but one, and that one died cuz i made the mistake of running it on a battery. once the voltage gets too low, fries the reg and the chip locks up.

    cool for delays. the chorus thing is a real bugger

  9. I have built two of these and my second one has some issues. The chrous effect is fine and sounds good, but everytime I disconnect the power the chip locks up. When I take out the chip of its socket and put it back again it works fine until I disconnect the power again. I have tried different chips and different power supplies but the problems remains.
    1. Any ideas on how to solve this?
    2. Is it possible to use the anti-lock board in the old Little Angel design in this design as well?

    1. I read a bit more and the anti-lock fix is in this version with the j112 as far as I understand, but the problem is still there.

  10. Built this and got it to work but the effect is noisy as hell. Getting all kinds of oscillating background noises. Scrapping this as there are plenty of simple cheap chorus pedals out there.

  11. Jack Orman posted a version two with minor changes that further improve the sound:
    (6V regulator instead of 5V)

  12. Works great with 4558 and J201. Little distortion with humbuckers but I have no noise at all. Maybe I was lucky with my PT2399 chip. Thanks for the layout.

  13. works fine, but there is any chance to increse chorus effect, depth pot half way start to land on vibrato thing, I like a mor ponunced effect whithout going to far