SOLVED wiper noise. different suppliers. different pedals. what am i doing wrong?

[likeyeah]

I'm at somewhat of a loss, and wondering what i'm missing.
I did a college search for the problem, but so far i'm still being new and stumbling around so hopefully someone can help me.
I've built 2 pedals so far, a stumble and a transcendence boost, and they both have the same quirk.

- all dirt is being generated by the amp itself, no distortion pedals on the pedalboard
- Both pedals sound as expected when engaged, (no distortion when played clean, etc)
- all pedals are on iso power, there's no hum or other issues.

both pedals exhibit wiper noise when i use the volume knobs at higher gains.
edit- it's a soft rubbing noise like a mic being dragged through fur or something.. no crackles or pops. just the sound of ...movement.

https://docs.pedalpcb.com/project/Stumble-PedalPCB.pdf

https://docs.pedalpcb.com/project/Transcendence-PedalPCB.pdf

Things i've done:

original pots were amplified parts sourced, replaced with ones from i love my switches.
original electrolytic caps were 'capacitor' brand caps, replaced with nichicon and (iirc) rubycon.
original ceramic caps were 'capacitor' brand caps replaced with vishays
the only caps i didn't change were the film caps, those are kemets.

what am i missing? thanks for helping a noob.

 

[pbrommer]

When you say wiper noise on the volume, you’re meaning the pedal volume/boost, correct?

I was thinking dc leaking to the wiper, but I’m wondering if you’re having issues I sometimes have: forgetting to turn the potentiometer all the way off or on to solder, which causes a burn/jump in the track.

If it’s just with your guitar potentiometer volume, then it might be something with something else. Hopefully that’s a start.

 

[likeyeah]

When you say wiper noise on the volume, you’re meaning the pedal volume/boost, correct?

yes i'm talking about the pedals. its tuner --> stumble + what's in its loop --> transcendence --> amp.
i've tested each pedal by itself also.

I was thinking dc leaking to the wiper, but I’m wondering if you’re having issues I sometimes have: forgetting to turn the potentiometer all the way off or on to solder, which causes a burn/jump in the track.

i remembered to do this with the replacement parts, was wondering the same, so i'd just gotten new ones from a different place... also noted the three second heat window on the data sheet the second time around.. so i just replaced all three out of hand.. no change.
the noise is smooth in the sweep.. so it doesn't sound like there's any hot spots for lack of a better way of conveying it.

how do i troubleshoot dc leakage in these circuits? thank you!

 

[spi]

are you saying the noise is only present when turning the knob? if so, are you planning on using the knobs when you're playing?

 

[pbrommer]

I’d double check voltages, DC before and after the cap coming off the opamps.

Maybe check the opamps and see if they’re good? Only other weird thought is bad jacks or bad cable - or something intermittently weird

 

[jwin615]

Overtightening the mounting can cause wioer boise as well. If you overtighten, it can damage the carbon track. Then, when/if you loosen the nut, the pot still has issues.
Finger tight plus 1/4-1/2 a turn is all that's needed.

 

[likeyeah]

I was thinking dc leaking to the wiper,

Only other weird thought is bad jacks or bad cable - or something intermittently weird

this got me thinking, so i scrubbed the pc board with iso again because i forgot to clean it up after swapping the caps and pots for the new ones.
it also dawned on me that when one clearcoats a finish.. wherever the clear paint hits, will be painted. even if it's just overspray. so i sanded the inside of the case around all the holes and also scraped the paint out of the screw holes in the bottom cover just to cover the bases..

the wiper noise is finally gone. Thanks for everyones input.. I'm going to try this on the other pedal too. it's probably the same issue.

edit- the tl;dr is don't rush.. the answer is both reply #1 and #4 in this thread because a) i forgot flux can make dc leakage and b) clear paint can make dodgy grounds to the case that look like bare metal.... but i picked reply #1 because there can be only one!