Ground loop

[Enduro800]

Just looking for a little help here. I installed my own amp and ran the positive down the driver's side with the speaker wires and the rca lines down the passenger side. I put the ground on the rear seat post and sanded down all spots to metal, but I keep getting that engine whine from the speakers. I was told it was a ground loop and my ground was bad. Can anyone give me some tips/pictures of how they did it? Its getting really annoying.

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[Radio Guy]

Ground loops can be caused from different components in a system being grounded at different points where the ground potential is not the same. The grounds will then try to equalize and current can flow on the grounded shield of audio cables inducing any noise like alternator whine into the audio cables. The proper fix is to ground your new amp to the same point other amps are grounded in your system.

It could also be that your new amp simply has insufficient DC filtering at the power entry point allowing alternator whine into the amp. In that case a good high current DC power line filter will usually take care of the problem.

 

[Enduro800]

Ground loops can be caused from different components in a system being grounded at different points where the ground potential is not the same. The grounds will then try to equalize and current can flow on the grounded shield of audio cables inducing any noise like alternator whine into the audio cables. The proper fix is to ground your new amp to the same point other amps are grounded in your system.

It could also be that your new amp simply has insufficient DC filtering at the power entry point allowing alternator whine into the amp. In that case a good high current DC power line filter will usually take care of the problem.

I'll look at the ground situation, plus where can I get that filter?

 

[Radio Guy]

This is cheap and can clean up some ground loop problems by isolating the ground between preamp and power amp audio cables.

https://www.amazon.com/Isolator-BOS...sprefix=car+stereo+filter,aps,161&sr=8-8&th=1

I’ll have to look around for high current DC power line filters, they can get expensive and I usually build my own.

 

[Enduro800]

This is cheap and can clean up some ground loop problems by isolating the ground between preamp and power amp audio cables.

https://www.amazon.com/Isolator-BOSS-Audio-B25N-Systems/dp/B000LP4RMG/ref=sr_1_8?crid=2KRBAP5UFJVFH&dib=eyJ2IjoiMSJ9.n6NGIBcX2CjH4jmSKY_roucSvWpCQXAUyzM7cYQOc0eJPG4nVuM0AmI2uYGrjZpBnE48tckToBTvAvTKfADUr1EClqGoO4ado3Mb2ROfbRHU_lmCNyH5A2bGxNJefSZkBWTv2A5OLHbGe6C59z8JDDAOWFQ23uIvsaj-fp4St95gBVzo35mc5CCSnV2gMytFyZKwHyxNGJ5e7yCxJinnvJsoEUtbBOrQNpQM7t1xvdM.d8KwYWJnLn8cg9hGShK2lw4oYslFuWjcDDx9UT1CzsQ&dib_tag=se&keywords=Car+stereo+filter&qid=1719944435&sprefix=car+stereo+filter,aps,161&sr=8-8&th=1

I’ll have to look around for high current DC power line filters, they can get expensive and I usually build my own.

I am using three of those for the amp (5 channel) and still have the whine.

 

[Radio Guy]

I am using three of those for the amp (5 channel) and still have the whine.

I like to prove things out and only buy what’s needed to fix a problem rather than shotgun it and stick things in until it works. With that said I would recommend testing the setup by powering the amp from a separate battery or power supply and see if the noise goes away. If so it could be either excessive alternator noise on the power line or a ground loop. You can then ground the power supply or second battery to the same point the amp was when the noise is there and see what happens. All this might help determine if another grounding spot will help or if a high current power line filter is needed.

I have a bunch of power line filters here so it’s no big deal for me to add one as a test but they can get expensive and if you have to buy one just for a test and it doesn’t work out it’s not a good day.

One question I have is the amplifier chassis screwed to the metal truck body providing a ground or is it’s ground wire the only thing on the amp side that’s grounded? If the amp is grounded through a mounting screw then it will be harder to establish another ground point with the wire when trying to reduce a ground loop.

 

[Enduro800]

I like to prove things out and only buy what’s needed to fix a problem rather than shotgun it and stick things in until it works. With that said I would recommend testing the setup by powering the amp from a separate battery or power supply and see if the noise goes away. If so it could be either excessive alternator noise on the power line or a ground loop. You can then ground the power supply or second battery to the same point the amp was when the noise is there and see what happens. All this might help determine if another grounding spot will help or if a high current power line filter is needed.

I have a bunch of power line filters here so it’s no big deal for me to add one as a test but they can get expensive and if you have to buy one just for a test and it doesn’t work out it’s not a good day.

One question I have is the amplifier chassis screwed to the metal truck body providing a ground or is it’s ground wire the only thing on the amp side that’s grounded? If the amp is grounded through a mounting screw then it will be harder to establish another ground point with the wire when trying to reduce a ground loop.

I have it on a board that is mounted to the truck

 

[Pilsner]

I have the issue on a stock system. It is worse when my towing lights are plugged in.

 

[Radio Guy]

I have it on a board that is mounted to the truck

Since you have a ground loop isolator in the RCA plug preamp path my guess is the new amplifier is not very well filtered on its DC input side and a high current power line filter may may help. If you were local to me I could loan you one to try out.

 

[Enduro800]

Since you have a ground loop isolator in the RCA plug preamp path my guess is the new amplifier is not very well filtered on its DC input side and a high current power line filter may may help. If you were local to me I could loan you one to try out.

Yeah, that seems to be the problem. Definitely would be nice to be closer to get some expert help.

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