Engine whine and ground loop fixes... take two

thank you for this thread!!! been trying to figure out why my kenwood kdc-x794 was whining. tried a bunch of things, then came across this thread and grounded the rca's with wire. worked like a charm! just wish i had seen this earlier... before tearing everything apart... haha

 
Hey guys - just read through this thread after getting my system installed in a new car.

Had it done by a shop.

Head Unit: Alpine 7897 - old school unit - but it rocks.

The shop definitely ran the power and grounds on different sides of the car (saw it myself when I showed up half way through the install).

I have 2 batteries (1 stock and 1 audio) - wired in parallel because my old isolator will not work in this 2012 Avalon.

Noticed the engine whine right away.

The Alpine 7897 has the rca outputs that 'dangle' out of the back of the unit. Is the ground trick still applicable?

I saw a pic in the beginning part of the thread that looked like it.

Is this trick something to even try with an Alpine HU?

 
Disregard. Ground loop was solved by running a new and larger ground from my head unit, to the body of the car. Sanded the paint away, self tapping screw and lock washers made for a solid grounding point. No more alternator whine!

 
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Ok I have a Pioneer x1500.

I fixed the alternator whine by wrapping the RCAs. Does this also apply to the sub rcas? My subs do not work now. They have their own ground running with the cables Which I attached to the main ground wire on the wiring harness.

THanks

 
Just want to confirm that running the power and signal too close together CAN cause this...to anyone thinking it's BS.

I recently bought a truck with a sloppy install, so I decided to clean it up and when I finished I had the dreaded 'whine'..and didn't introduce any new equipment to the system. So I pulled up the carpet again and separated the signal and power wire (I ran them right next to each other for a good 3ft) and problem solved.

I've also had luck grounding the RCA's to the head unit on another install.

Thanks CarAudio.com community for all the help and info!

 
Hey y'all. Found this thread via Google search and figured I'd post up my situation and see if anyone has helpful advice.

Problem Description: Soft background hiss/whine when engine is running that is noticeably louder than the normal amp hiss (which goes away when I turn the gain down). It is not a high-pitched whine that goes up and down as I rev the engine. More like the sound of a low-rpm motor running at the same RPM regardless of the engine RPM. There is a slight variation with engine speed but its not the screeching whine I've heard before in other cars.

Install notes: Pioneer AVH-5600BHS HU, Infinity 474a amp, Infinity reference speakers front and rear. Knukoncepts Basik RCA cables. Klarity 14 gauge speaker wires. 4 gauge battery lead, 4 gauge ground to clean, scraped attachment to body. RCA cables run up opposite site of car from power.

What I've Tried: Unplugging RCA from the amp stops the problem. So does puling the RCAs from the HU. Interestingly, only 3 of the four RCA cables (and therefore speakers) is exhibiting the noise. I can pull the front 2 channels and one of the rears, have pure sound coming from the remaining speaker without background noise. As I plug in the remaining leads, they will each have the background noise.

No effect/improvement: Isolating the amp from its mount. Swapping RCAs to different channels. Running separate RCAs directly between HU and amp

Made problem worse: Grounding the amp body. Grounding body of HU with separate lead. Wrapping wire around RCAs on back of HU and grounding to the HU body (per the first post on this thread). Each of these made the ticking noise noticeably worse.

Not sure what to do next. What is puzzling me is that one of the channels is NOT having the noise, yet is wired exactly like everything else. FWIW, that channel doesn't exhibit the noise regardless of which cable I use, so the problem follows that signal channel, not the RCA...

Any suggestions short of using a pair of GLIs? (by the way is there such a thing as a "good quality" (or better quality) GLI, or are they all bad in terms of attenuating signal and flattening dynamic response?

 
I have the same issue. When I have just one pair of RCAs plugged in, there is no noise. But as soon as I plug in the other set, there is noise. Doesn't matter which goes first. Seriously puzzled. Did you ever resolve this?

 
I have the same issue. When I have just one pair of RCAs plugged in, there is no noise. But as soon as I plug in the other set, there is noise. Doesn't matter which goes first. Seriously puzzled. Did you ever resolve this?
you have a piece of equipment inducing noise into your system due to a bad ground, faulty internals, etc

 
Amps are grounded separately on sanded down metal (floor under seat bolt front, floor under seat bolt rear). HU separate ground wire to firewall. Was told that I should ground my amps to battery instead of floor due to way new cars are made. Suggestions. I have a 2009 Sienna. BTW. Thanks mitchell0715.

 
Amps are grounded separately on sanded down metal (floor under seat bolt front, floor under seat bolt rear). HU separate ground wire to firewall. Was told that I should ground my amps to battery instead of floor due to way new cars are made. Suggestions. I have a 2009 Sienna. BTW. Thanks mitchell0715.
I wouldn't ground to the battery unless you know your car has a body with terrible resistance, and even in that case I'd ground to the engine or frame then run a ground from your frame up front to the battery. If your car has no frame id ground it to the engine then upgrade your engine ground to battery.

Start a new thread so we can assist you better, include what amps, headunit, etc you're including. keep it concise but provide as much info as possible and you'll get my help as well as a few others.

the short story for what i think your problem is, is that there's a difference in ground impedence between your amps and the excess difference is being transferred through your RCAs when the second piece of equipment is plugged in

 
Another Pioneer sucker.....installed new amp...WHINE.....with the help of adulbrich we narrowed it down to a few things. Tried in order of "how easy" and it was probably the 4th thing on my list.....GROUND THE RCA PLUGS!!

A huge thx to adulbrich, I have been tearin his inbox up and he doesn't hesitate to help, as well as others.

Awesome forum.....yall have been nothing but help!! I appreciate all the replies in other posts.

Okie

 
After re-installing my setup, I noticed alternator whine at low volume. Checked the grounds on both amps, making sure they were as short as possible. I'm using Streetwires Musica100 and 200 RCA cables along with OFC Streetwires power & ground wires BTW.

Come to find out, it was the MTX 250x amp. Swapped it back to the Alpine 3547 and noise was gone. In some cases, it's a component causing the noise, other than a headunit.

 
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