hum in system, ground loon? 60hz?

Maybe you do, maybe you dont. How loud is it? First, make sure your interconnects are all on tight, then try a cheater plug. Then move the cables around. Im not sure exactly about the cables but I am sure someone will respond with how to do that. Then, tell us what preamp and amp you have. Lots of them alone or in combination produce a low level 60 hz hum/buzz audible close up but usually not at the listener's chair. Good luck.

Thanks Paulwp, I have a Bat VK50SE and a Bat VK60. Electraglide AC cords and Transparent and cardas interconnects. Hum occurs with any source. It's not very loud and doesn't change with volume control. I can't hear it from my listening position, but can within 4 feet or so...

My suggestion would be to go work from the speaker backwards. Disconnect everything but your speaker and power amp, short your power amp inputs. If your hum is still there, it's the power amp. Try lifting ground in that case. Work your way back through pre-amp and source.

A note of caution here; there is a reason why this stuff is grounded, it is for your safety, so be careful.

You don't have anything hooked up to it that touches a cable line do you. No video souce whatever. I found out that anytime I connect any video device, even a DVD player to a tubed preamp I got a ground loop hum. I tried the Mondial magic box and floating grounds on all different pieces. It improved but the only way to totally eliminate it was unplug the video device from the back of the preamp or switch to a solid state preamp. I know many of you will be dissapointed to learn that I finally chose the latter. If no video source touches your preamp, I don't know, but you could try floating the grounds.