|
I personally have not noticed any audible hum in a properly working 5-tube radio with new filter capacitors...I usually use 47 mfd for the first capacitor after the rectifier cathode and 100 mfd for the second one. Have had no trouble with that.
You may be able to just hear hum if you put your ear right up to the speaker but not otherwise.
You certainly could just leave the 35W4 filament in the circuit and shunt the AC input to a solid-state power supply maybe using a 1N4007 diode with a surge resistor ahead of it if you wanted to go for more capacitance. You probably could build it on a terminal strip inside the radio.
|