Another area to look into is the cartridge clips and their connection to the tonearm wires. Reverse the ground wires at the cartridge to determine if a wire or a cartridge channel is bad.
You hadn't mentioned if the hum is from both channels or just one. Maybe you could more fully describe what is and isn't happening.
The old "Grado Hum" is typically from proximity to a running motor and is generally not loud. Since you have a loud hum even with the motor off, it would be unlikely that that is the problem, although you shouldn't rule it out completely.
You hadn't mentioned if the hum is from both channels or just one. Maybe you could more fully describe what is and isn't happening.
The old "Grado Hum" is typically from proximity to a running motor and is generally not loud. Since you have a loud hum even with the motor off, it would be unlikely that that is the problem, although you shouldn't rule it out completely.