My newly aquired Usher 1.2 appears to have a bit of a ground loop problem. The amp is at one end of the living room whilst the pre-amp is in the dining room with the rest of my equipment. Obviously they are both using different mains sockets. When nothing is playing through the amp there is a constant low buzzing sound coming out of the speakers. Dynamic Turtle who I bought the amp off told me he had a similar problem that was cured using a ground loop isolator.
My questions are what do I need to do to stop the ground loop noise? Can I just buy an isolator off eBay? Is there a better option?