dgilley,

It sounds like the hum originates at the TV. You might want to try a simple test. One of the most common causes of ground loops is cable TV. They are on a different ground than your home and so the loop is induced. If you have cable unhook it and see of that is that eliminates the hum. If so, there a number of products (Jensen Transformer makes a simple inline ground breaker you put on the cable) you could try.

If that does not work then the Ebtech might be the answer. Before I spent a bunch of money I recommend you spend some time unhooking everything in your HT and then hooking it up until you get the hum. That process will help you ID the cause. The other day in the Saloon a Gunslinger reported a problem with some outside lights that induced the hum. Ground loops are frustrating but usually can be solved after some detective work. Let us know your progress.