I just swaped out my 7125 (two prong) for the 7700 (3-prong) and I have MASSIVE ammounts of hum. I am not talking about a little distracting but where that's all you could hear out of the speakers!!!

I was using two power conditioners to handle all of my equipment so I ran a wire between the ground lugs on both units and the hum was cut down by about 75%. I then found the source - it's the light kit on my celing fan! A few months ago I put a dimmer switch in and I am sure this is doing it as I have heard they are well know for that, do they make a special kind of a dimmer that does not introduce massive ammounts of noise?