Vintage amp hum - cap replacement

[dude]

Put the PT center tap ground with the other HT grounds, leave the a/c ground separate.
Other then all the ground changes, try tubeswells suggestions, carbon comp R’s can cause hiss.
Most tube amps will have some hiss when volume and tone stack are pegged, your volume pot pegged stopping hum might be that its shorts out when rotated full on, if you turn it back a hair, it will stop if this is the issue. You can change it but if it’s the problem, why not just turn it back a hair.
You could used shielded wire on that vol wiper putting the cap on the tube, ground the shield at back of the pot, like l suggested. You did this for the input jack, do it to the vol wiper.

[Erik Aa]

I tried removing the AC power wires from the volume pot switch once again, but this time moving them even further from the wires going to the tube plates and that helped a lot. I will make a separate on off switch at the other side of the chassis, next to the place where the AC wires enter the chassis.

Once this is done, I will move the center tap ground away from the AC earth ground and over to the other power section grounds.

Once this is done, I will try some shielded wire as suggested if needed. And maybe some resistor replacements.

But getting the AC power wires far away from the filter caps and the wires going out from these helped tremendously. It is fairly quiet now. A slight very quiet hiss when increasing volume especially when the Tone control is up. But much less than before.