Alternator whine

[LIGHTBEING 10+ year member]

Sometime during taking my trunk apart, removing my amp, replacing it and putting the trunk back together, I got some engine/alternator noise.

So when I remove the RCA's I don't hear it anymore - so it's safe to say it's not the HU?

It's either the RCA's or ground loop?? What exactly is a ground loop - just a bad ground?

So either replace the ground location or the ground cables???

Thanks

Jordan

Click to read more...

 

[PhatTonyDeMarco 5,000+ posts]

Sometime during taking my trunk apart, removing my amp, replacing it and putting the trunk back together, I got some engine/alternator noise.
So when I remove the RCA's I don't hear it anymore - so it's safe to say it's not the HU?

It's either the RCA's or ground loop?? What exactly is a ground loop - just a bad ground?

So either replace the ground location or the ground cables???

Thanks

Jordan

Wrong. If you remove the RCA's and the problem stops, that would tell you the problem is at the head unit or it is being picked up along the RCA cables.

Check the entire length of the RCA's for pinches, bare wire, and anything else that might introduce noise.

To further isolate the problem, replace your RCA's but do not 'hide' them inside the vehicle, just let them run across your interior so you can be sure there is nothing affecting the cable. If the problem persists, you have a head unit problem to deal with.

 

[LIGHTBEING 10+ year member]

Wrong. If you remove the RCA's and the problem stops, that would tell you the problem is at the head unit or it is being picked up along the RCA cables.
Check the entire length of the RCA's for pinches, bare wire, and anything else that might introduce noise.

To further isolate the problem, replace your RCA's but do not 'hide' them inside the vehicle, just let them run across your interior so you can be sure there is nothing affecting the cable. If the problem persists, you have a head unit problem to deal with.

So it's not a ground problem? I'll try and get to it this weekend.

 

[60ndown 10+ year member]

if you had no noise before moving the amp, id guess its something you did ,'while moving the amp' did you screw the amp into the metal of the car?=bad juju. try moving the ground.or clean the paint from where the ground is attached,or remove the screws holding the amp.

 

[LIGHTBEING 10+ year member]

if you had no noise before moving the amp, id guess its something you did ,'while moving the amp' did you screw the amp into the metal of the car?=bad juju. try moving the ground.or clean the paint from where the ground is attached,or remove the screws holding the amp.

No the amps are in a false floor, screwed into wood. It would seem it was something I did, but I'm not exactly sure what? My ground is under the false floor and it goes to a huge distro block.

 

[helotaxi 5,000+ posts]

Disconnecting the RCAs breaks the ground loop which is why the noise goes away. Double check your ground connections, all of them, including the one going into the amp itself.

Did you replace old amp with the same modelo r was it an upgrade to a different brand? Some amps are simply more susceptible to ground noise than others.

 

[LIGHTBEING 10+ year member]

It was an upgrade to a different Brand - Here is something I didn't mention. The amp that I upgraded was my sub amp - SS VGA1600.2 to a US MD2D - I kept my comp amp - SS Reference 700S. Now, I discounted and dismounted the 1600.2 and just left the RCA's taped up until I got the new amp - MD2D. It started, right then, so I figured it could have been the RCA's that were taped up touching something ? possibly

I also unplugged the RCA's going to my 700s - just to test the signal - then plugged them back in - I also should mention that I was testing them with a DMM - and didn't exactly know how to so I was kinda playing around with the different test settings on the DMM.

The next day I get in my car and I hear the noise - just figured it had to do with the disconnected RCA's and I was hoping when I got my new amp in, it would stop......

 

[helotaxi 5,000+ posts]

Which amp are you getting the noise on? Was the amp on or off when you disconnected the RCAs?

 

[LIGHTBEING 10+ year member]

The 700S - it was on

 

[LIGHTBEING 10+ year member]

morning bump - just checking to see if anyone noticed anything I did wrong in the above post. I won't be able to get to it til this weekend so the more feedback the better.

Thanks again