Tube Amp Archive

For what it's worth, disconnecting the wire from pin 1 of the PI tube to the 82k resistor eliminates a significant amount of hum.

Sorry it took so long to get back. Here are pictures of the interior. Gingertube, I don't think that I'm quite understanding your suggestion--just me being dense. The grounding scheme is grounds associated with V1 & V2 are tied tgether including from volum/tone/tremolo controls. The V3 ground has th...

Unfortunately that did not make a difference.

I will give that a shot (hopefully tonight) and report back.

I have a 6G3-based amplifier that I recently built that functions well, but has a pretty nasty 120 Hz hum that seems to be localized to the phase inverter section. Simply pulling tubes, neither the first nor second preamp tubes have an effect on the hum, but pulling the PI tube eliminates the hum an...