Axiom Home Page Forums General Discussion Technical Questions Humming from EP350

Okay Kokil, continued(if you're still reading this). So the problem was in fact that the sub amplifier was grounded at two different points and their electrical potential was different enough to cause a hum current to flow between them. If you want to keep the sub in your preferred spot(without running an extension cord)there're at least two solutions: break the ground which runs through the sub power cord by using a "cheater plug"; or break the ground which runs through the shield of the sub cable to the other equipment. If you use the cheater plug the sub isn't grounded through its power cord but is still grounded, as Bren mentioned, through the shield on the sub cable. This is considered to be a less reliable ground and there's a fairly remote danger involved, but the call is yours.

If you want to keep the ground through the sub power cord and cut the one through the sub connecting cable, besides performing surgery on the cable, you might pick up a ground loop isolator such as this one at RadioShack to connect between the end of the sub cable and the input on the sub. You'd also need an RCA plug-to-plug coupler such as this one to connect the cable plug to the isolator plug.

Hi BrenR and all,

This suggestion is fine if you're on conventional cable. But this will not pass High Definition digital cable signals (5 MHz to 1.5 GHz) without degradation. The Axiom cable ground-isolation transformer will pass all HD signals with no degradation, which is why we introduced it.

http://www.axiomaudio.com/groundisolator.html

I did abunch of tests with various models until we found one that passed all the HD signals untainted. Note, this transformer and other isolation types cannot be used with satellite dish receivers.

Regards,
Alan

True. I keep forgetting that some people get that new-fangled HD stuff.

Bren R.