Replacement Amp arrived today. I have not had any popping or humming from the old amp since the last occurrence but it has stopped working briefly once since. As of the time of swapping amps the old one seemed to be working ok though.
Upon removing the amp boot I noticed that the red speaker wire terminal that goes into the black boot was loose (the actual binding post itself was very wiggly.) This was the only thing I could see visually wrong with it and not sure if it is the cause of my random periods of "non subbage" or not.
New amp seems to be working just fine, hopefully this will be the end of my troubles. shipping my old amp back to the US depot tomorrow.
