This is a library of perfboard and single-sided PCB effect layouts for guitar and bass. I'm not an electrical engineer by any stretch of the imagination, just a DIY'er who likes drawing layouts. It is meant for the hobbyist (so commercial use of any of these layout is not allowed without permission) and as a way to give back to the online DIY community.

Wednesday, August 12, 2015

Little Angel Chorus

Here's a simple, fairly low parts count chorus based around a PT2399, designed by Rick Holt (aka Frequency Central) from the DIYStompboxes forum. I've drawn 2 versions, one with board-mounted pots, and one off-board pots. The 2nd IC (NE5532 in the layout) can be any dual op-amp (a TL072 works well), just socket and experiment. The board is fairly large, so you might want to use long leg right angle PCB mount pots and mount them from the component side to save space. Here's a quick sound sample.




46 comments:

  1. Hi,

    The PCB on the top - the second pins of the parts from 6,7,8 pins of "PT" must go to ground.

    Verifed

    reg.
    Martin

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    Replies
    1. Thanks for catching that and verifying. Fixed!

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  2. I Builded this pedal but doesn't work!!!

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  3. The second pcb says that depth 1 and speed 1 are not connect, but the first are connected.

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    Replies
    1. Either way will work the same. They're just being used as variable resistors and either method is acceptable.

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    2. Maybe my ic doesn't work. Thanks.

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    3. I found error in my pcb, i fixed and works great. Very nice pedal, thank for Effects Layouts!!!

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    4. Hi Could you please share what the error was? If it was a common one

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  4. I build this, its working, but the depth is like not many effect, somebody can modified for the depth ?

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    Replies
    1. which PCB?? the 1st one or the 2nd one ?

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  5. Is there any replacement for the pt2399? I cant find it anywhere

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    Replies
    1. Afraid not. It's a really common chip though now. I got 50 of them off eBay for like $10 US.

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    2. Emilio - try HT8970 as a substitute

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  6. yeah I figured it would be plenty of those around since it is a pretty popular pedal in the diy community here (argentina) I guess it is just bad timing with the stores stock. Thanks anyway!

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  7. Simple good chorus, vibrato tone there. Slightly lacks depth, but in general everything is great. Thank you very much. Checked with the LM4558, jrc4558,LM833,TL072.

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  8. which of the layouts work ? The first or second

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  9. I try this pcb, it's working. But, i get many hiss in sound :(

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  10. I did it today, very good Chorus, not better than Small Clone, but you can have a nice tone. Thanks!

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  11. I try to build this Chorus. It's working ! But, the hiss sound "sssssssssssss" very big. :(

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    Replies
    1. I have the same. what is the solution?

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    2. Try replacing the PT or up the value of the power filter cap.

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  12. This comment has been removed by the author.

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  13. Board mounted PC works great. However I did have a failed IC which caught me out for a few mins! I'd post a picture but can't work out how.

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  14. Perfect chorus, perfect sound for soloing and some clean tones too. First I tried with Entropy chorus which seemed more interesting, but after two tryings I did this design at first attempt. Great job!!! Nice PCB layout!!! Greetings from Balearic islands!!!

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  15. Note: I don't know why but it sound better with TL072 than 4558, less effect... our maybe less gain, but I kept 072 ;)

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  16. I built it for three times, but i got same problem. it work but sometimes doesnt work. what the solution?

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    Replies
    1. i faced similar type of problem with a Delay pedal made with PT2399.
      Probably its the same here. Try different PT2399

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  17. Built this today, I am getting sound through the effect but no chorus effect. Went through and triple checked component values and traces for errors, couldn't find any. Has anyone else experienced this problem? Any idea where to go from here?

    Power is checking out at all locations, getting 5v at the regulator, op amp is working fine, clean signal comes through but no chorus effect. :/

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    Replies
    1. Me too. Same problem. Passes signal, but no chorus effect, just some unwanted gain...

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    2. The same problem.. any of you can resolved this?

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  18. Did you know any mod to increase the Depth of the effect?

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  19. In the onboard pots PCB, the "Underside (reversed) image is not mirrored.

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  20. I've build this today.
    Only problem is the output is amplified and distorting,
    And it has no high frequencies in it.
    Checked component values and traces.
    If i pull out the PT2399 it sounds fine but no effect.
    Tested with multiple IC's

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  21. can i make a request for a daughterboard of this chorus to solve the lock ups of PT2399 and its pin outs?

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  22. and also can i request for the little angel chorus with lock fix and noise reduction measures from rick holt's design? extra pad for space/warbler switch and chorus/vibe switch? thanks and more power..

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  23. Hello,

    How could I add a volume pot at the Little Angel circuit ? Is it possible to do just changing some resistor by a pot ?

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    Replies
    1. You could just tack on an A100k pot to the output. Lug 3 to the out pad, lug 2 to out, lug 1 to ground.

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    2. It´s a good idea, however this A100K pot to the output will not be only a volume attenuator ? I mean, I would like to control the unity gain of the circuit.

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    3. So, to Adjust the volume (unity gain), the output volume must to be (very) higher when the pot is rotated clockwise in the maximum position.

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    4. Try adjusting the value of the 1M resistor by the 5532. Or make that a trimmer/pot.

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