Ground loop is eating my lunch (again)

[KeithL]

Kind of. The problem is that even a tiny amount of voltage between grounds can be a problem (and it's actually difficult to measure it accurately).

Feb 2, 2017 20:33:35 GMT -5 Boomzilla said:

Might it be easier to measure for voltage between the coax shield and the grounding pin of an inside socket?

[Boomzilla]

Thanks, guys - today's been busy & I've not had any time to mess with the system at all... So tomorrow's work day for getting it all straightened out.

[klinemj]

So, I am unclear on the basic wiring here. Can you elaborate? I get that you are running the oppo analog out to one amp and the digital out to another (via a preamp). But, is each amp going to the same speakers? Do you have a speaker switch to select which amp out goes to your speakers? If not, then what are you doing?

(Skip all the grounding detail you have mentioned already...i want the big picture first.)

Mark

[Boomzilla]

Hi Mark -

No speaker switch. Each amp has its own wires & I switch them back & forth at the speaker terminals to move from tubes to SS and vice versa. If I opt to keep this setup, then I'll build a heavy duty speaker switch, but for now, I don't mind swapping.

[bluemeanies]

Boom...I am not being vivcious here....but with all the hours you have tried to figure where this ground loop is coming from not to mention the time on the FORUM.
I have to ask.
Why especially since it's the weekend now and if you do not have anything that is of a special nature with Mrs. Boom today might you take the time even if "IT IS A PAIN IN THE A_ _ take your system apart and each time you introduce a new piece of equipment into the line you WILL determine where the ground loop is coming from in your system.
It is a proven method.
I know I have mentioned this idea prior and it did not get any accolades but it is the best solution...mentally.
If you continue with the ground loop which BTW after I found my problem and introduced COMCAST in the mix I had to purchase a device similar to the one mentioned by qdtjni.
It worked.
Start with the basics instead of wasting time on the forum trying to eliminate which seems to me to be a ongoing problem that has not improved or given you any good direction.
Just my opinion Boom and wanting to help.

bluemeanies

[Deleted]

run a speaker wire from the ground screw on the back of the pt-100 to a screw on the metal chassis of the crown...i did this when one of my inukes had a ground loop....and this got rid of it

[Boomzilla]

I work weekends. I work nights. I work whenever the client needs deliverables. My hobbies take back seat. bluemeanies - your suggestion is excellent - but by trial & error, I've already determined (99.9%) that the source of the ground loop IS the Oppo. I'll double-verify it today by unplugging the HDMI cable from the Cox box. If that's the problem, then I'll buy one of those cable ground eliminators. If not, then I'll do the "one at a time" thorough test that you propose.

Why post such a thread - because I'm not the only one with such problems, and by asking (publicly), I get good answers like yours, bluemeanies, like Keith L.'s and like qdtjni's. AND those answers remain available to others.

Cheers - Boom

[DYohn]

You really should buy the right tools for your application and stop doing things like "swap speaker wires" or avoid using proper preamps. If you really want to have a single source with two amplifiers and a single set of loudspeakers, get a preamp with multiple outputs and a speaker switch, and if you are ALSO trying to interface the same source with a home theater system, then you'll also need an A/V preamp for the HDMI. Build the system you want, do it with the correct tools.

[niuguy]

FWIW when I had a ground loop problem it was the COAX coming into my cable box. I was able to fix it by purchasing this rather pricey ground loop isolator: www.amazon.com/gp/product/B0017I3K9M/ref=oh_aui_search_detailpage?ie=UTF8&psc=1

[Chuck Elliot]

Feb 4, 2017 13:03:00 GMT -5 niuguy said:

FWIW when I had a ground loop problem it was the COAX coming into my cable box. I was able to fix it by purchasing this rather pricey ground loop isolator: www.amazon.com/gp/product/B0017I3K9M/ref=oh_aui_search_detailpage?ie=UTF8&psc=1

I had the same problem. Solved with Jenson VRD-1FF

[novisnick]

Feb 4, 2017 12:20:30 GMT -5 Boomzilla said:

I work weekends. I work nights. I work whenever the client needs deliverables. My hobbies take back seat. bluemeanies - your suggestion is excellent - but by trial & error, I've already determined (99.9%) that the source of the ground loop IS the Oppo. I'll double-verify it today by unplugging the HDMI cable from the Cox box. If that's the problem, then I'll buy one of those cable ground eliminators. If not, then I'll do the "one at a time" thorough test that you propose.

Why post such a thread - because I'm not the only one with such problems, and by asking (publicly), I get good answers like yours, bluemeanies , like Keith L.'s and like qdtjni 's. AND those answers remain available to others.

Cheers - Boom

If we look back in time, there are similar questions in the past. Today we have more modern answers.
Yamaha 3020 and an XSP-1 had the same problem.

Everyone benefits from open discussion.