I wouldn't worry much about the interference but the power draw on the outlet. It is better to plug the big Denon to a dedicated outlet so it does not have to share with other big consumers such as a large screen plasma TV. The AVR-4520 has a fairly large power supply, large enough to deserve a 15A circuit all for itself if possible. Again, at volume position 65, that AVR should not clip, not for the kind of music you listen to anyway, but if you load the 15A circuit up too much especially if the feed to the receptacle is long, the Denon may not be getting the 120V that it needs to do its best. I would also bypass the Tripp Lite, plug the Denon directly into the outlet for best performance.
By the way, would you please do some of us a favour and change the volume scale to relative so it will read from -79.5 to +18 dB?
