10" Ground wire too long? Whine.

[Brady]

Did an amp install this weekend and getting some whine. Not really sure what to check. I have about a 10" long ground to the nearest point grounded to a bolt on a cross bar. Possibly removing paint under the bolt would help.

 

Or, could it be an issue of the RCAs and Speaker wires running next to each other?

 

Not my car, but my buddy is a total n00b on car audio, so I've been the primary installer and trouble shooter thus far, and this is only my second install ever, and it's been 3 years since my last efforts, so I'm a little rusty and not up to speed anymore.

 

He has an Alpine (don't know model number) headunit w/ sub preouts, JL Amp (don't know the series), JL woofer in stealthbox. Amp in trunk, RCAs running about 4-5 feet from head unit to amp and speaker wires running same route back. Power cable is about 2 feet away until they reach the sub.

 

Any thoughts on possibly mounting a GLI somewhere?

 

Thanks,

Brady

[PGT]

don't wuss out and get a GLI. The length of the ground is fine....you need to make sure it is a solid ground. It there's paint, that's not solid. Wire brush it. Also, take a digital MM and test the differential in ground between the CD player ground and the amp ground.

[johnAWD]

Are the RCA cables shielded? I've run 20' RCA lines before, but they were run as far away from the speaker lines as possible (rca down driver side, speaker down passenger side). Where is the power line run - inside the cabin or under the car? If inside the cabin, close to the RCAs?

 

A 10" ground wire isn't too long - just be sure it's got good connectivity to your grounding point. Verify the head unit grounding as well. I've had issues in the past with the generic head unit ground vs the antenna lead, which also wanted to act as ground.

 

How about resistor spark plugs? They've also helped me in the past with 'alternator whine'.

 

$0.02 worth.

[Brady]

Ok, I'll check those out. I believe the RCAs are grounded, but to be honest, I didn't check. The RCAs are DIRECTLY next to the speaker wires running down the center console. The power is running inside the car along the passenger door sill, about 2 feet from the cables.

 

I'm somewhat thinking that the paint is my biggest issue right now, but I'll have to start there and trouble shoot.

 

Thanks guys and let me know if you have any other thoughts.

[gfxdave99]

I'm going to jump on this thread instead of starting a new one, I have started to have an issue with some light alt whine, however it only happened after my aftermarket HU was installed..

 

Since i had tweeter do it should i just take it back and let them figure it out or are there some quick things for me to check given that it only happened after the HU install.

[Boulderguy]

90% of the time alt noise comes from incorrect or poor grounding. Rule 1 is ground everything at the same point & make it a good, clean ground (IE clean the paint off). If you can ground your headunit where your amps are grounded you'll probably kill the noise.

[IanKen]

90% of the time alt noise comes from incorrect or poor grounding. Rule 1 is ground everything at the same point & make it a good, clean ground (IE clean the paint off). If you can ground your headunit where your amps are grounded you'll probably kill the noise.

 

++1

 

Alos, do not route the line level feed from the HU along side the power feed for the amp. There's not a shielded cable made that can be zipped tied to 12 feet of power cable from the battery and not have noise induced into it.

[jim malach]

Try a full grounding kit thats what I did and the whine came right out

[mbanks21]

Have him install it properly first, than worry about grounding kits and other stuff. The power wire should be as far away from the RCAs as possible. And try a differant grounding point or clean up the ground he has now.

[Brady]

I already have the power as far away as I can without making the rca's and speaker wires twice as long as they are now (or maybe even longer!).

 

We will try the grounding point at the amp one of these days when I have time to see him again, and good point on the ground at the battery. I wasn't too impressed with the ground from the battery to the car. Maybe that could be cleaned up too.

[Boulderguy]

Moving the RCA's away from power wires rarely fixes engine noise - it would be a complete myth if it didn't occasionally work. The entire car's a big EM field, every metal surface is a power wire. You're not getting away from it. And as long as your RCA's are shielded, which they are if you got them anywhere but the flea market, they shouldn't pick up radiated noise.

 

If you want to test the theory, get a second set of RCA's - really long - and run them over the seats between amp & headunit. You'll probably still have noise.

 

All about the grounding...

[PGT]

 

I bought really expensive RCA's and used a JL Master Ground Lug and I have a hint of noise that comes and goes. Sometimes, no matter what you do, it's there. Given how tight my amp rack is, there's no avoiding power close to signal.