Weird oscillation I get with all my builds...

[Barracuda]

So nearly every time I build a pedal I have this problem *I build fuzzes most often*. This is a "Wooly Mammoth" style fuzz so I get why I'd have problems with it, but I think this is a bit different. At first I had a 250pf cap between base and collector on Q1, this just squealed like a fuzz factory basically, I didn't ground the input on bypass so you could even hear a ringing through bypass. I added a 500pf instead and while it has stopped squealing you can hear the oscillation on the end of held notes. This wasn't biased to be spitty, more crunchy, so notes should have held without any gatey oscillating sound. But the notes do hold, you can just hear this oscillation in the background. I've attached my pedal guts and a clip of what it sounds like.
There is also a 100uf cap on the power jack, 220uf, 100uf and 220nf caps on board power. The second footswitch is a toggle for mids + a Big Muff output stage (for volume/tone recovery) which works in conjunction with the second pot (on the right).

https://www.dropbox.com/s/b0k9465pf14yc5u/oscillation.mp3?dl=0

https://www.dropbox.com/s/6w0uf1gku2wyy64/oscillation%20img.jpg?dl=0





This happens, like I said, almost every build. Am I missing something??


EDIT: I've been told by someone that linking my audio and power ground bus directly can cause this kind of problem? or at least, not help..
And also to lather my ground track in solder to stop interference

[thermionix]

And also to lather my ground track in solder to stop interference

I don't see how that could help.

My attention is drawn to this pot:



It's not too clear, but it looks like you tried to solder Lug 1 to the enclosure to ground it.  Solder won't bond to aluminum (die-cast, pot metal, whatever).  If it seems like it sticks, it's just the flux acting like glue, not an actual solder bond.

[Barracuda]

Ah, okay, thanks for the tip, it has grounded for this build, but I may wire it to the jack lug to help.