Thanks Ernie, looks an interesting article that I will read given 5 mins.

In answer to your questions:
Yes, the power amp and controller are located together.
The multiroom controller has a three pin mains while the power amp has a two pin.
I will look into your suggestion and I'm sure this will solve the problem.

This one has thrown me a little bit as you can virtually turn all the lights on in the house (dimmers and all) and there is no hum but as soon as you switch one about 3 specific circuits the hum is introduced.
Why is nothing ever simple!

This message was edited by cmo on 10/14/02 17:43.08.