AB165 Bassman Noise Issues

[Ted]

Removed.

Amp not an AB165 despite label

[pdf64]

The (shared) 3rd stage shouldn't have much gain, maybe 6dB (< 470/220), so shouldn't raise the noise floor significantly.
MF resistors can help, though ensure their voltage rating, often <250V, is adequate for all conditions.
Are you sure all the ecaps have low ESR, and the 12AX7 are not overly hissy?
Numerous connections are made to the chassis 0V common; it's good practice to re-establish them all to ensure they're effective, low resistance

[Ted]

The (shared) 3rd stage shouldn't have much gain,

Interesting. The 3rd stage of this amp isn't shared. - In fact it doesn't correspond to the schematic I posted despite having AB165 on the label. It's more like an AA864 circuit where the 3rd stage isn't shared.

Is it possible to delete this thread?

[Enzo]

Believe the circuit, not the label.

[Ted]

Removed.

Amp not an AB165 despite label

Believe the circuit, not the label.

I really ought to know that by now