Hum in the system

Thanks for all your responses. I was on the phone with MSB tech support and their suggestion (after we had tried a couple of other things) was to use a cheater plug. That worked.

A quick follow-up. It turned out that the hum was caused by a faulty power supply. MSB sent me a new power supply and voila!, no hum. I don't need to use the cheater plug any longer, which I am really glad about. Again, thanks for the suggestions.

You can buy a cheater plug from any hardware store - it is essentially a 2-prong plug, with a 3-prong socket on the other end into which you can plug your component's 3-prong plug. It is NOT intended as a device to drop the ground - it has a little metallic tab that you are supposed to screw into the wall plate - of course, if you do that, you will not have dropped the ground so people tend to bend the tab back, away from the wall plate and thus effectively drop the ground. Hum caused by hooking up a TV or VCR to your amp or receiver is cause because the cable is grounded separately from your power line - this causes a ground loop hum. In order to get rid of this hum, you have to isolate the cable ground - the safest way to do this is to buy Mondial's MAGIC box - which stands for Mondial Antenna Ground Isolation Circuit. Essentially, you connect it to the cable outlet in the wall and then run another cable from the Box to your TV or VCR as the case may be. This will get rid of the Ground loop caused by Cable TV, guaranteed. Note, that the Magic Box only has inputs and outputs that accept the standard coaxial TV cable - it can only isolate hums caused by cable tv - NOTHING ELSE - as some people seem to mistakenly believe.