I am experiencing something like that in my speaker testing setup, since I am still waiting for my equipment to arrive from Outlaw.

I have a Bedini Class A amp connected to an old Nad which I am using to test my speakers and found I was getting a "noisy grill" effect as well.. (even though none of my speakers actually have a grill)

They are all on the same circuit and seem to be having some kind of inconsistant EM problem, cause if I move them around a bit, etc, it stops for awhile. I am also having problems with the pots in the NAD, so that could have something to do with it as well, but its just old and I am not going to fix it.

Does you EQ have pots or is it all digital?