I would fix it or find someone to work on it. Maybe change the resistor and rectifier and drop in a new set of tubes and see what you got.
IMO, worth fixing.
For reference, there's a used working black face EAR here locally going for $750.
EAR 834P - Sale or try and repair...
I have an EAR 834P and the volume is decreasing on the left channel. I opened the case and the tubes appear fine. However, there is some browning on the breadboard on one wire (coming from the toroidal power transformer), to the single phase bridge rectifier, and resistor (breadboard: P5, D3).
I have done some simple soldering (ex., DIY bottlehead amp) just not sure about diagnosis this issue.
Otherwise, I plan to post it on the forum for sale. Just hate to take a loss on the price if it is a simple part replacement.