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Ammeter Shunts And Ground Loops

Printed From: the12volt.com
Forum Name: Car Audio
Forum Discription: Car Stereos, Amplifiers, Crossovers, Processors, Speakers, Subwoofers, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=148563
Printed Date: April 07, 2026 at 2:38 PM


Topic: Ammeter Shunts And Ground Loops

Posted By: couchflambeau
Subject: Ammeter Shunts And Ground Loops
Date Posted: March 23, 2026 at 3:56 AM

Hello all,

I'm in the process of installing a large audio system and installed a shunt on the ground side of my amplifier rack which then goes to a common piece of 2/0 wire that goes to my chassis ground in the back of the car.

Im noticing an alternator whine with the car running. I believe the shunt is rated as 200mV.

Can the shunt resistance be causing a ground loop?



Replies:

Posted By: lee.lopez
Date Posted: March 24, 2026 at 10:04 PM
I wouldn't know if that's the cause or not.

I would run a jumper wire from your head unit ground to your amp ground and see if that gets rid of it. That's worked for me in the past when even ground loop isolators failed.



Posted By: couchflambeau
Date Posted: April 04, 2026 at 5:47 PM
Certainly can't hurt.... I'll give it a try!


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