Turbo Tube Screamer ticking/tremolo issue

[thermionix]

I don't think it matters what you plug into it, the instability would be in the circuit itself, if that is indeed the problem.

[Voltzy]

I don't think it matters what you plug into it, the instability would be in the circuit itself, if that is indeed the problem.

OK right, looking up some causes of amp motorboating it looks like it is usually caused by a bad capacitor, or some bad decoupling... The only capacitor that is different when in turbo mode is C14 coming off the rotary switch, and I have already tried swapping it out to no avail.

I might try lifting the ground connection of R18 off the board and wire up a separate star ground for it.

[Voltzy]

OK so I tried starring that ground point which didnt fix the problem and I also soldered a 10uF cap across the power pins of the op-amp which also didn't fix the problem.

I am about ready to give up on this thing, does anyone else have any more suggestions?