Head-Fi.org › Forums › Help and Getting Started › Introductions, Help and Recommendations › Need Help With Grounding Issue
New Posts  All Forums:Forum Nav:

Need Help With Grounding Issue

post #1 of 8
Thread Starter 

Hello all, I have what I believe to be an odd grounding issue with my A/V system. I have a cable box with hdmi to my Samsung lcd. Line level audio out from cable box to Creek 5350SE amp connected to Revel M106 speakers. I have everything plugged into one power conditioner.

 

I’m hearing what I believe to be a ground-related hum/buzz that gets louder when I turn up the volume. If I UNplug the TV power cord the buzz gets much louder. If I UNplug the hdmi from the tv or the cable box the hum gets much louder. If I unhook the coax feed to the cable box the buzz goes away, but then the system is useless. If I take a wire and ground the metal end of the hdmi cable to a screw on the outlet where I’ve plugged in my power conditioner the hum gets quieter. 

 

The really annoying bit is that I can’t use my sub due to this issue. The creek has a preamp out and a power amp in that is normally connected with a jumper. I tried sending the preamp out to my sub and the line out from my sub to the power amp in, so the sub separates the bass from my monitors. Problem is the sub massively amplifies the hum so that if it’s turned up loud enough to hear the bass it’s nearly drowned out by room-vibrating background hum.

 

From what I’ve read, it sounds like the a/v line might not be properly grounded to the electrical ground as it comes into the building. Since I rent I’m not sure I have the ability to fix that. I think that putting an isolator on the coax line would fix the hum issue, but since I have digital cable, it will completely mess up my service.

 

Is there any easy way fix this? I have a feeling it’s a combination of a crappy cable box, a grounding issue and/or using a 10 year old integrated amp. I’d rather not have random wires strung from my tv into the electrical outlet if possible.  Thanks!

post #2 of 8

I have the same problem - two different ground potentials between the cable and the house wiring.

 

Get an isolation transformer for the coax.  The Jensen is the "Cadillac", but I believe there are less expensive ones out there.

 

 

post #3 of 8
Thread Starter 

Are you saying that these guys really don't interfere with digital cable? I bought a cheap one a while ago that claimed it was compatible but broke my cable service.

post #4 of 8
Quote:
Originally Posted by mrip541 View Post
 

Are you saying that these guys really don't interfere with digital cable? I bought a cheap one a while ago that claimed it was compatible but broke my cable service.


It works with mine.

 

One interesting thing though, I have a long run from the wall to my system.  Which end I put the transformer on did make a difference as far as signal strength loss.  I think they mention that in the documentation.

post #5 of 8
post #6 of 8

Has it always done this or just started? If it just started have you tried swapping cables?

post #7 of 8
Thread Starter 

Thanks for the help all. I've always had some background noise, but I actually was having even worse hissing/hum issues after recently changing my system config. Moving or even touching one particular set of interconnects would clearly affect the sound. Kinda funny, those cables are the only "audiophile grade" cables I own and they are the worst. I replaced that set and the new ones don't have the same issue, but the background hum remains.

 

I read that audioholics page and ordered a Jensen isolator. I'll let you know how it works out.

post #8 of 8
Thread Starter 

Quick update: The Jensen isolator fixed it. Wow. Would have saved myself so much trouble by not getting the cheap one the first time around.

New Posts  All Forums:Forum Nav:
  Return Home
Head-Fi.org › Forums › Help and Getting Started › Introductions, Help and Recommendations › Need Help With Grounding Issue