Leaky tone/coupling caps

[ViperDoc]

I'm testing a newly built amp, all seems to work generally well except for some oscillation I believe is happening in the preamp. I've been testing DC-to-ground on the wired preamp and I start to get a swirling sound that gets quite loud at the volume knob output and bright switch, starting at the tail of the treble cap. Prior to that, I get no sound except for voltage test clicks. I found the recommendation to disconnect the low-voltage end of a cap and probe DC-to-ground. When disconnecting the bass and middle "TMB" tone stack capacitors, with the chassis lit up, I get a wavering 0.1-0.5 mV positive/negative DC-to-ground reading on a Fluke DMM. What amount is tolerable, or should it just be ZERO?

[Charlie Wilson]

New caps? .1 of a volt I would not like but .1 millivolt. Don’t think that is the issue.
CW