engine feedback

[DaMoNe6969]

havin problems installing a simple stereo in my new car.. Its a 95' BMW 325i..

as soon as I hook up the RCA's to the amp, I get engine feedback through my back factory speakers.
The battery of my car is in the trunk, so I have the amp wired directly to the battery, + and - so they arent no where near the RCA's..

Would grounding the Amp directly to the battery cause this??

The amp is powering a 10" sub and is not connected to the factory rear speakers

[PaulD]

more than likely, you're RCA's are running close to a noisy source

[dave92cherokee]

At some car stereo shops you can get a RCA ground loop isolator which hooks inline with the rca cables and has a grounding wire that you just connect to a good chassis ground behind the radio and will eliminate almost all noise.

[CBFryman]

ground loop isolator and alternator wine are different problems. get the RCA's away from any noisy source.

If that doesnt work, the only otherthing yo ucan do with out ocmprimising SQ/ouput isto find a diode and place it inline with the Power Wire. This will filter out all non DC current to the amp.

[PaulD]

Originally Posted by CBFryman

ground loop isolator and alternator wine are different problems. get the RCA's away from any noisy source.

Not really, alternator noise is often inducted into a system with ground loop problems. This is when the reference ground for the signals in the headunit are at a different potential than the reference ground for the signals in the next stereo unit down the "RCA" chain. A ground loop isolator is a transformer on the RCA lines that breaks the physical connection.

[kram5527]

Keep the RCA's away from power lines that source current. By transformer action, the alternator ripple can be induced in the RCA lines even if the power line is not tightly magnetically coupled to the RCA's.

[pimprolla112]

^ do what. There is a simple answer and it was already posted hes most likely getting interference from within the cars chassis. Whether its a ground, power wire, signal wire for something else.

How do you magnetically couple the RCA's to the power wire.

I did install a ground loop isolator on my older car for the speaker amp, it had horrible feedback, fixed the problem slightly still had some feedback but the way this one was it sounded like the damn car was reving with the amp to an exact tune. It was horrible. It was a combination bad ground, bad rca path and not enough experience. My first install.