Middleman
Professional Amateur
Distortion at lower levels than you have been experiencing prior can be some of the following.
Cracked or leaky capacitors in the preamp stage
Failing tubes
loose speaker coil
I'd take it to the shop unless you have a background in tube amp repair.
Cracked or leaky capacitors in the preamp stage
Failing tubes
loose speaker coil
I'd take it to the shop unless you have a background in tube amp repair.