I need help with hum

My Bryston does not have digital ins like a HT processor. The hum definitely seems to be from cable TV, because I initially hooked up just the DVD player to test it with CD's and it worked fine. As soon as I hooked up the TV the hum started. I'll see what I can find at Radio Shack. The Mondial Magic box is $150 on Audio Advisor, I'd like to fix this much more cheaply. Thanks to everyone who responded.

It's the ground on the cable.

There is a bunch of info on this over at AudioAsylum.

The problem is that there are two separate grounds - one for the power and one for the cable. They are often at different potentials which causes current to flow (so you get a hum).

Check the forums at AA for possible solutions.

Here is a link that will help you resolve your immediate problem http://www.hometheatertalk.com/ubb/Forum1/HTML/003322.html