Ground Loop Video and advice.

http://s1343.photobucket.com/user/fkmc123/media/IMG_1696_zps39c20b57.mp4.html

Any idea why this would be happening and a solution to fix? The two interconnects are L/R RCA's coming from my receiver to a Preamp. The power cable is from the preamp to a Richard Grey 1200C. Any time the power cable is not touching the two RCA's there is a ground loop. Or if I touch the RCA's the loop stops but not all the time. I've tried lifting the Preamp, with no change.

Thanks to anyone who can help.