SOLVED Curious Dream behaviour

[mittens]

Very new to pedals so forgive me if this is obvious, but I didn't see any similar issues posted in the forum.

I put together the Dream Fuzz last week and it is great. Acts as it should...at first. Not a lot of noise when disengaged. Quiet when it is on and no signal from a guitar. When the pedal is off the signal goes through to the amp normally.

Problem is that after playing for around 10-15 minutes, a high squeal starts and builds and builds until it's unbearable. I can prolong the normal behaviour by dialing back on the sustain pot but the squeal catches up quite quickly. The squeal is only when there's no signal. eg. in between chords or when muting etc. Everything seems normal with the board. Any ideas what this could be? Would a bad capacitor cause an issue like this? Or a cheap power supply start.to build squeal? A bit stumped. Not sure how to troubleshoot this one. Any suggestions would be really helpful.

Thanks!

(For reference an image of the board is attached before i cleaned up some sloppy wite strands on the 3PDT and swapped out the stereo jack for another mono)

 

[music6000]

How did you insulate under the Tone pot & PCB?

 

[mittens]

How did you insulate under the Tone pot & PCB?

I didn't insulate, but the pot casings are plastic. I'll pull the board out and see if there's anything funky happening on the board under the tone pot. Thanks.

 

[mittens]

Went through the components again. Found that the ceramic cap at bottom right became microphonic at a certain point. Replaced it with a mylar. No more issues with the squeal buildup behaviour, though it doesnt sound quite as smooth overall. Solved.