Help with PedalPCB Pitch Witch Build

[Guava]

Wondering if somebody can help me figure out what's going on with my Pitch Pirate clone built on a PedalPCB Pitch Witch board.  The pedal works and the warped delay effect range is really cool, but it's doing a weird thing I think is related to not allowing any clean signal through.  As I turn up the delay, there is an increasingly significant gap between when I pluck a string and when the note sounds.  I'm wondering if the blend function works, because with the blend completely off, no signal passes.  And there's never any clean signal that passes with any blend pot setting.  From the demos I've heard, there should be a clean signal with the delay layer over it.  Could this be a bad PT2399 by any chance?  Or a bad double gang pot?

[mjg]

If you are getting no clean signal, I'd try an audio probe along c3, r1, then the blend pot, to see where the signal is disappearing.  You should get clean signal regardless of the delay chip. 

[somnif]

A few pictures of the board would help as well, could be a bad solder joint or incorrect resistor value, and extra sets of eyes can help with that.

And if you're very ambitious you could start collecting voltages on the circuit.

[Guava]

Here's a picture of the board.  Haven't used an audio probe yet—hopefully there's an obvious mistake?

[Jay.lingelbach]

Did it work before boxing?


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[Guava]

Actually didn't try it before boxing.  I'll pull it out and see if that makes a difference.

[somnif]

Well the resistor values around the dry line are the correct values. Cant see the cap values on the brick blobs, though.

Couple of the pads on the dual gang pot look like they may be a bit light, but that could be lighting in the picture.

I'd say you have to ways to go:

1) Audio probe it, particularly the bits between the 386 and the output (C3, R1, dual gang). Attach some sound to the input, power the circuit as normal, then poke around with the probe.

(thats a 100nF cap as the probe)

2) Pull it out of the enclosure and see if the problem changes/persists. Could be a ground fault on part of the dualgang, something touching something it shouldn't.

I'd say do both, but the order is up to you

[Guava]

Removing it from the enclosure worked!  It looks like the dual gang was shorting out on the enclosure.  I only had a pcb mount pot that didn't fit, so modified it by clipping the legs and soldering wires to the holes adjacent to the pot, which must've left just enough solder height to touch the box.  I'll just tape it all up and should be good to go. Thanks for the help guys!