[codefox1]

Agree, and please post image or link to schematic. Old repairs may or may have not been done correctly. There is little to gain from increasing values of filter capacitors unless a field coil choke has been cut out and a PM speaker installed. Then, yes, but mind the specs for the rectifier tube.

If you can, swap the output tube(s) with known good ones. Many times gas or other defects cause hum. Of course lots of "modern" gadgets cause all kinds of havoc with antique equipment. Dimmers, battery chargers, computers, portable phones, flourescent lamps, new lamps, modems, etc....