I just recently made a change to my office's sound system. My old setup: Minijack-to-RCA out to a 8 channel mixer, from there RCA out to some M-Audio studio monitors and minijack out (via the mixer's headphone port) to some other monitors with a sub. I also ran my iPod into the mixer, via 1/4" TRS. The mixer, Sub and M-audio are all powered (no ground). I got some big Bose speakers so that I can get the full range (high from the small monitors, mids from the M-audio, and lows from the Bose) and needed a way to power them. So, I dug up a aiwa receiver (simple, six input stereo, also not grounded) and ran the RCA out from my mixer into the receiver, looped the M-audio speakers through the receiver's OUT, and powered the Bose with aiwa's amp. The top-of-the-range speakers remained connected via the mixer's headphone out. Everything seemed to work okay and I was pleased with the range I was getting. Today I plugged in my external monitor, a cheap :Hansol 15" LCD. It's grounded. Buzzzzzzzzzzzzz! I cant, for the life of me, figure out why the monitor is causing feedback, when my old system worked perfectly fine. The only thing I can think of is since all the audio cables and the VGA and power for the monitor run together (they say not to do that...) that that would be causing a problem, but it was like that before and was okay. Help?