beejohn

So I just installed my system. My friend gave me his old 4x75W alphasonik amp, so that's what I have hooked up. connected to the stock head unit.

Ran RCAs on right side of car, Power on the left side of the car.

So, ONLY when I have my rear speakers connected do I get an alternator whine coming from the speakers. I know for sure it is an alternator whine because when I turn the AC on the noise becomes much more audible.

With the AC off you can still hear the whine of the alternator as the RPMs increase, but ofcourse not as loud.

Why is there no alternator noise when only the Front speakers are connected!?!?

i'm also using the blaupunkt adapter for rca outs. and i grounded the rca outs to the headunit, this reduced the noise slightly. but mostly it is still there.

i'm pretty sure it's not the amp either, because I switched the Fronts to ch. 3 and 4, and the rears to ch. 1 and 2. still the same exact problem.

shaners256

originally I ran the RCA along the left side of the car with the power cable. Then, I switched the RCA cable over as a test to run just along the center console and it still had the whine.

I did buy a noise reducer from WalMart to see if that would work. It did take most of the noise away when I had the RCA running alongside the power cable, but not all of it. Now that the cable is running alongside the center console, it is not as noticeable, but it is still there.

I have a blaupunkt aftermarket HU.

AudiDreamr

Radio Shack sells a noise filter to reduce alternator whine. It plugs inline with the RCA's- if you have the RCA's running parallel to any other power, you will get the whine- especially when it's under load! Do the fronts whine too when the rears are connected? You may find additional (more helpful) resources in the audio forum.

beejohn

hmm, i think what you are talking about is a ground loop isolator.

will try one out, see if it makes a dif. thanks

AudiDreamr

Every time I've gone to a car stereo place or even an auto parts place looking for a ground loop isolator, they give me one that goes on the top of the ignition coil or something. The one I am referring to is inline with the RCA's, not the power system.

eug (MK V)

Did you ground the wires?

RedBlackYellow

i have an inline isolator in my RCAs and no buzz sound!

1999Audi

http://audizine.com/forum/showthread.php?s=&threadid=53136&highlight =amp

or do search there