From goffmac747@aol.com Sat Dec 09 22:00:09 2006
Subject:Re: Sort of OT: Electrical 60hz mains hum elinination without risk.

The ground problem may not be in the mains plugs but in the patch cord connections, 1/4", rca, what have you. Again too many paths to ground. Reason why companies like RANE use a system where the patch cable has one ground connection lifted within the cable itself on one end. Something they ask the user to do with an ordinary connection. Also try checking if any metal chassis of your boards are touching other metal chassis. In a live situation a simple metal power junction box touching a metal electrical conduit pipe caused a ground loop and when that connection was broken the hum stopped in the P.A.