Thanks all - John's comment seems to indicate I may just have to deal with it until the new EP-600 arrives. The hum is pretty low right now and probably more noticeable because I have the volume turned all the way up on the sub to keep up with the Axioms.

Now... if the EP-600 also hums, we'll have a much bigger problem because a 'small' EP-600 hum will probably be audible from outside the house versus the current problem which is only audible when the room is fairly silent. ;\)

Epic 80-800: HG Cherry