What am I hearing from this amp?

I recently bought an Anthem MCA5 series II amp to add to my Integra 8.2 receiver and Kef ref 2~2 speakers. With the receiver connected to the speakers,the speakers are dead quiet with any setting on the volume knob. I added the amp from the pre-outs of the receiver with my 5 speakers hooked to it. At -55db from the right front channel I could hear a slight hiss 9" away from the Uni-Q driver(mid and high). I could hear a quieter hiss from the left front channel. All other channels were dead quiet. I unplugged all the interconnects leaving the speakers hooked to the amp. I then heard what sounded like air moving from the same speakers, but the hiss was gone. I could switch the spkr connects and the sound would move to whatever was connected to the front right and left channel. Is this a ground loop hum? or something else?
The amp went to Anthem and they say nothings wrong with it. Any suggestions or thoughts would be appreciated.

Are you hooked up with cable TV? If you are, disconnect the feed and listen again.
I did try disconnecting the cable feeds and power cord and still had it.
A hiss heard from 9 inches away is normal for most gear. If it was very noticeable from 9 feet away you might have a problem. There's lots of things in life to worry about, but this isn't one of them.
I would say that when you don't hear the "hiss" from the receiver and hear it from the receiver/amp combo it is just the added amplification. The hiss probably present in the receiver but not noticable until the amp amplifies it.
Also it may be a RFI/EFI in the cabling between the receiver and amp that you're picking up. Try a sheilded cable
Thanks for the input all.