Never ending Alt whine

[Eldorado 5,000+ posts]

tried that....only worked for a minute //content.invisioncic.com/y282845/emoticons/crap.gif.7f4dd41e3e9b23fbd170a1ee6f65cecc.gif

then we got arrested

 

[ravendarat 10+ year member]

Just to verify, this is a whine that increases and decreases with the rpm right, not like a popping sound? Just making sure. Out of intrest, what kinda speakers are running in this system. I have actually had crossovers back feed into the system and cause engine noise because the crossovers were burried in the dash and picked up some crazy field. It wouldnt make sense being it stops when the RCA's are unplugged but at this point nothing really make sense right. And for point of reference, when I did my system I ran a 12 gauge power and ground from the head unit to the batteries installed in the rear of the vehicle to avoid problems exactly like this as I had issues with noise in the previous system I had installed in the same car. Never had a problem after so you might wanna check into that. Also verify that the ground on the battery is good being you said it stopped when you used a external battery. It could be something just that simple.

 

[Eldorado 5,000+ posts]

Yes, goes with the RPM

Its active so no crossovers. 3 different sets of tweeters have been in there so its not them

Ground is as good as its going to get. It was the same noise in the stock location with the stock battery.

 

[ravendarat 10+ year member]

What was the resistance reading on it?

 

[Eldorado 5,000+ posts]

on what

 

[supa_c 5,000+ posts]

Bump this mother because this still never got fixed...

We will be trying another amp soon to see if the problem still occours

 

[da12b 10+ year member]

GET A NEW CAR...LOL.

Did you try a ground loop isolator? It might work. Try it. You'll never know untill you try.

 

[thatsgonnahurt 10+ year member]

try a ground loop isolator. fyi a healthy alternator makes noise. problems arise when audio components are poorly designed for a car, such as having poor isolation.

 

[supa_c 5,000+ posts]

We tried an isolator, didnt do anything

 

[thatsgonnahurt 10+ year member]

The other time that there was no whine was when the HU power/ ground was isolated aswell as the amp being isolated.you found the problem, poor isolation! one question for you. what do you mean by isolating the amp? are you saying that you needed to provide an isolated 12 volts for the amp at the same time as the hu? or are you saying that the amp wasn't touching the chassis?

 

[supa_c 5,000+ posts]

everything was wired directly to the battery.

The amp is in a false floor, no metal contact at all

 

[jaco 10+ year member]

actually take the car to an alternator shop and have it tested.

i used to rebuild alternators at a shop and, when

an alternator blows a diode it will cause that wineing sound through audio.

and it will still charge fine, but not at 100%

 

[thatsgonnahurt 10+ year member]

everything was wired directly to the battery.The amp is in a false floor, no metal contact at all

wiring direct to the battery does not supply an isolated 12 volts and ground. but i find it interesting that the noise went away when this was done. it suggests that if you moved your wiring away from stock wiring the noise would go away.

an isolated 12 volts and ground means using a 12 volt battery or 120vac to 12vdc converter and not making any electrical connection to the chassis and powering the component/s off this.

i've read over these pages and noticed some great troubleshooting tips already but i'm going to reiterate some of them. when the rca cables are disconnected from the amp and the noise goes away this means the noise is entering upstream of the amp, headunit, rca's, etc.. so how does one troubleshoot these components. to troubleshoot induced noise in the signal cables move the hu over to the amp and use short rca cable's or gender changers. if the noise is gone new rca cables should be considered and you could try rerouting your present cables. if induced noise is not the culprit the noise can be coming from a hu that has poor isolation. use an isolated power supply (additonal battery that doesn't make an electrical connection to chassis) to supply power for hu. you will have to move the hu so that it does not make connection with the cars metal. if the noise goes away then an isolated power supply should be considered, but these are expensive, it may be cheaper to buy another headunit. http://www.davidnavone.com sells isolated power supplies. when using an isolated power supply it is necessary to isolate the component/s from the chassis as well as any of its wiring that may tie to the cars electrical system which would negate the benefits of an isolated supply.

 

[supa_c 5,000+ posts]

We used an isloated battery on the amp and h/u, the noise was gone. This was the only time it was never there. When we isolated the h/u only on the battery, it was still there.

We used isloated RCA's, noise was still there.

Jaco's post seems like the only logical thing to do since it sounds like something that would happen..

 

[supa_c 5,000+ posts]

actually take the car to an alternator shop and have it tested.i used to rebuild alternators at a shop and, when

an alternator blows a diode it will cause that wineing sound through audio.

and it will still charge fine, but not at 100%

hmm, sounds about right.

We get mad dimming and the amp is only 180A and not even close to full tilt.

We got it tested at autozone but the girl didnt know WTF she was doing.