If the hum is physically coming from the amp, specifically from the power supply transformer, that is DC offset hum. This is eliminated either with something like a Humbuster power strip, or by trial and error to find what is plugged in or wired that is causing the offset.
If the hum is heard to be coming out of the speakers then this is ground loop hum.
So as usual we start with precisely identifying exactly what it is we are talking about.
If the hum is heard to be coming out of the speakers then this is ground loop hum.
So as usual we start with precisely identifying exactly what it is we are talking about.