Argh nagging ground loop issue

[stangman67 10+ year member]

Well this buzz is resilient! I have had ground loops in the past and have been able to solve the problem. Highs amp is a new jvc, custom comp set, Kenwood HU. All quality knu wiring. Rf rca's. Diagnosis I have done.

Symptoms- audible buzz when music is playing. Buzz is constant volume, does not increase with volume

1. Ipod directly to amp inputs works great, no buzz whatsoever.

2. Tried 2 different sets of rca's and they yielded the same results- rca's are run on the opposite side of the power wire

3. Regrounded the hu to multiple places, all yielding the same results, BUZZ!

4. Amp grounds check out fine, this is not the issue since the amp works fine with an ipod directly hoked up, speaker wires are fine for this same reason.

I have not grounded the rca's yet but I guess that will be next. I am tempted to just say **** it and use a ground loop isolator but a large part of me says that is not the right thing to do.

Any ideas?

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[fasfocus00 5,000+ posts]

the ground loop isolator may or may not work, it's a make or miss thing. have your tried using a DMM to figure out if your ground is giving a uniform result for both your HU and amp? ground the RCAs and see what that does? do you have any signal processors between your amp and HU?

 

[stangman67 10+ year member]

Yes I checked continuity on the grounds, all checks out just fine. I have no signal processors at all, directly from the hu to the amp. I'll try to ground the rca's, if that doesn't work I will go pick up an isolator, even though I don't want to. I need tunes for the road trip tonight and tomorrow.

 

[CHEMMINS 10+ year member]

Does the buzz freq go up when you rev the engine?

 

[stangman67 10+ year member]

Nope, happens with the engine off too, so not alternator whine.

 

[CHEMMINS 10+ year member]

Deck grounded properly?

 

[stangman67 10+ year member]

Read my original post.

 

[CHEMMINS 10+ year member]

Try a line output converter to run the rca's. Intrested to see if the rca connection in the deck is hoopitied.

 

[stangman67 10+ year member]

Eh not worth the money to do that. I'll get a ground loop isolator and if that doesn't work I'll have to look into a new deck or something.

 

[CHEMMINS 10+ year member]

Take the deck to the local shop, hook it to their board....

 

[stangman67 10+ year member]

Grounding the rca's fixed it.