So just recently my amplifier has begun to hum. I came here yesterday and did a search and found some info, but I'm still stumped as to why it just recently started humming. The amp in question is a HK Signature 2.1 that I purchased off of ebay over a year ago. I have changed nothing in my setup. Yesterday I plugged it directly into the wall instead of the power strip, removed the cable feed to the television, and even unplugged my sub which is on a different outlet but none of it helped. The amp uses a two pronged connector so I guess I can't use the cheater plug I see mentioned in many posts. My next step I suppose will be to run an extension cord from somewhere else in the house and plug my amp in. I'm not sure what else to do. Is my amp just showing signs of age? The humming is coming from the very front of the amp and while not very loud, is very audible in my bedroom system. Any help would be appreciated.