sunking harsh distortion

[jtn191]

hey, I'm troubleshooting a build I did for a friend. The only substitutions were BAT41s for the diodes and I subbed a 1.5K resistor for R20 instead of 1.8K because it was the closest I had...
Anybody think it's R20? It sounds closer to my Rat than my previous sunkings...

Maybe it's opamp distortion? I used an audio probe and it sounds the worst on pins 2 and 6 on IC2. on 2, it sounds fuzzy and on 6 it sounds like fuzz/broken/misbiased

[jtn191]

bump, I've tried changing the opamps

[jkokura]

First thing I'd suspect is either a wrongly labled part, or that you've put the wrong part value in place (i.e, 10K instead of 100K).

Jacob

[jtn191]

I checked all the resistors and voltages--something seemed to be off on IC2 and the charge pump so I swapped charge pumps. It seems to be a bit better, but there's still some weird stuff going on...
Tone control is acting weird (doesn't roll of treble much/as usual ccw, and it seems like it adds gain CW). There's static when the volume gain pot is turned all the way off, even when it's disengaged and running through just the buffer.

[jkokura]

At this point, it sounds like you're doing the right things. The problem is that you're getting sound, so it's hard to find the point where it goes bad.

Keep working the steps. Voltages may help us look for things. Good pictures of both sides of the PCB would let us double check things for you as well.

Jacob

[jtn191]

I'm exploring this further...
This is technically on Aaron at BYOC's "klone" board but the circuit and numbering is the same.
I found that I'm hearing distortion on R11, C8, faintly on C7 and on pins 6&7 of IC1
It's tricky because the build doc doesn't show the layout/part numbering. will keep exploring...

[jtn191]

Aha! It looks like R11 is 930K instead of 422K (430K). Looks like I need to make a post in the Parts Jar. I'd be willing to paypal a few bucks