Axiom Home Page Forums General Discussion Technical Questions Ground Loop Isolator - Thoughts?

I need to get one to get rid of my subwoofer hum.

Copy and paste the link below to see one that I've found on Ebay.

http://urlsnip.com/043197

Thoughts?


.

Link police...

http://urlsnip.com/043197

I'm not familiar with that product -- the Scosche line seems to be aimed at car audio -- but assuming it is an isolation transformer intended for audio use it should work OK.

That's what I was thinking. Car audio or home audio, it SHOULD work for both.

I tried somthing like that from RadioShack to get rid of the hum from my sub, it didn't work for me.

Check out my experiences with ground loops, and the solution I found, here:

http://www.nextlevelav.com/forum/showthread.php?t=733

The punchline: the EbTech HumX worked like a charm.

link

Okay, I think that I've got it figured out.

I lopped the ground plug off of an old extension cord to test the sub, and voila, that worked. No more hum.

Question: If I buy a power supply loop eliminator, do I just plug the subwoofer into in, or should I plug in the whole power bar that is suppling my system (audio and video).

Moorthy,

CUTTING OFF OR OTHERWISE BYPASSING THE GROUND OF A 3-WAY PLUG IS DANGEROUS!

Many people do defeat the ground prong of a three-way plug to address ground loops. ALL these people increase the risk to themselves, and members of their household, of electrocution.

There are safe, low-cost solutions - the Ebtech HumX is merely one of them.

No worries, it was just for a test.

I've already removed the "doctored" extension cord.

Okay, where can I get a Ebtech HumX ????

I've searched to no avail. The US distributors that I've found do not ship to Canada. I just love that.

Is there a similar product sold in Canada ???

Have you found the source of the ground loop? I would look to correct what is causing it in the first place.

I would second Wid's comment. If you isolate the cause, you may not need anything else. I think that Alan has an article on this website, somewhere, on ground loop isolation.

One of the most probable causes is from the cable TV line. Try disconnecting it and see if the hum goes away.

I did remove the coax cable from my receiver, and that freatly decrease the hum from REALLY bad, to noticeable.

That, was step 1.

After that, using an extension cord, it plugged the subwoofer into two other different circuits, but that didn't work.

The only thing that did work was to plug in the sub WITHOUT a ground. Knowing full well that that is not safe, I'm looking to get an isolator.

Getting one, at a reasonable price from a Canadian distributor, would be ideal.

M, since breaking the loop at the sub power cord works, but you don't want to risk the sub amp possibly developing a short and not being grounded except through the sub cable, try breaking it at the sub cable. Pull the sub cable out of the input far enough so that the center conductor still makes contact but the outer grounding shield doesn't; see if this stops the hum. If it does, try to fashion a little strip of plastic or even paper to keep the grounding shield from making contact even when it's fully inserted. If it works, cheap. If not, there have to be Canadian sources which sell isolators.

Or roll your own cable... get two RCAs and some 75ohm cable of your choice, connect pin to pin, and the shield on one end only. Voila... hum-less sub, and a cable to the perfect length.

There are even crimp-on RCA connectors if your soldering isn't up to par.

Bren R.

Moorthy, what kind of sub do you have? If it is an Axiom EP500 or 600, have you tried removing the Chassis Ground screw on the back plate?