I have recently added a second zone to my home theater setup using the multi-room feature of my Marantz SR-7000 receiver. I have the Marantz connected to a Parasound HCA-855 amp, to a pair of B&W WP-1 speakers. When I turn the Parasound on, and then turn on any of my source equipment (DVD, CD, VCR, etc.) that are connected to the Marantz, I hear a loud buzz through the second zone B&W speakers. The odd thing is that when I turn off the source equipment, the buzz continues for about 20 seconds and then disappears. The tone and volume of the buzz are also affected by whatever is playing on the source equipment (flipping the channels on the TV clearly alters the tone). I suspected a ground loop, but disconnecting the CATV has no effect. My interconnects are decent (Audioquest Sidewinder, XLO Twinax) although they do travel past several power cords (at right angles as best as i can manage). I have no problems with any of the other equipment when the Parasound is turned off. All are connected to a Monster surge strip to the same outlet (other than a powered subwoofer that is not the problem either). Any ideas? I have tried a search but can't seem to find a thread that replicates my problem.