Grounding Hum

It's Monster Cable interconnect cable, if that helps. Besides taking the cable apart, is there a way to tell if it's shielded?

I finally (3+ days) figured out. I pass along this update in the hopes that it helps someone else out. The source of the hum wasn't grounding at all. It was airborne RF given off by a Kodak camera dock in a distant room. All I can figure is that the electrical circuit for that device went through a wall behind my stereo system.

A big thank you to all those that responded.

Never mind what I said in the previous post. The buzz returned. After venting my frustration, I went to turn the volume up on the preamp, so I could the noise while I went around the house searching for the source. When I went back to the preamp, I inadvertently touched the faceplate, thereby grounding it, and the hum stopped. My conclusion is that the preamp itself is having a grounding problem, that only be heard when the phono input is selected. So the issue becomes one of grounding the preamp. Any suggestions? I don't want to have to act as the ground myself...

I didn't read back in this thread...but have you tried the phono input with the phono unplugged...and plugged in? Is there a difference? You might have a loose ground wire in the cartridge assembly/connector. Can you try with the cartridge removed?