1962 TrueTone 4DC6231-A

[Hi-Fi-Mogul]

Voltages:

V1 = Left Channel 1 (noisy hum)

PIN 7 Plate VDC = 118

PIN 1 Cathode VDC = 3.4


V2 = Right Channel 2

PIN 7 Plate VDC = 122

PIN 1 Cathode VDC = 3.4

When I switch tubes b/t channels 1 & 2,
channel 1 grid1 VDC is always higher
than channel 2 grid1 VDC.

Readings of both tubes in Channel 1 position:

Grid 1 Pins 2-5 : VDC 0.11 and 0.11

Readings of both tubes in Channel 2 position:

Grid 1 Pins 2-5: VDC 0.005 and 0.004

[electra225]

If you have two volt meters you can connect to the grids of both tubes. Leave the meters hooked up and let the amp run for awhile. See if the grid voltage increases as the tube gets hot. You can cover the amp with a cardboard box in order to hold in the heat. If the grid voltage increases by 1 volt or more, I'd say you have grid emissions. If it doesn't increase at all, then your problem is elsewhere.

[Hi-Fi-Mogul]

No apparent grid leak, Greg.

I'm gonna place this amp in a box for now.

I've spent a week on it, and I want to work on something
else, that will give results.

Thanks for the inputs so far, everyone.