Tracking down oscillation in a Krank Rev1

[Danglin' Fury]

Just spitballing here.... but you said the oscillation gets worse when you touch the gain pot shaft....could tube possible that this pot is part of the problem? I know you said all the grounds seem good in a continuity test, but the pot may be internally damaged.

[DFuller]

That was my first guess - it's a new pot, known good.

[Danglin' Fury]

Damn... ok...that sounds like a booger!

[alexradium]

almost every 4 stage amp has a snubber on third stage anode resistor,or a couple smaller on 2nd and third,that's good measure in preventing oscillations.