If there is no hum with all inputs disconnected then the problem does not lie with the amp, unless you still get the cone movement with the volume control turning which will be a separate issue if so.
“Music has always been a matter of energy to me, a question of fuel. Sentimental people call it inspiration, but what they really mean is fuel. I have always needed fuel. I am a serious consumer. On some nights I still believe that a car with the gas needle on empty can run about fifty more miles if you have the right music very loud on the radio”
Hunter S Thompson