I have an Alpine CDA-7998 headunit and I'm running it to a 5 channel amp in the trunk. I've had noticeable alternator noise coming just from the front left speakers (can't hear anything in the other speakers from the driver seat and none of my other passengers can hear anything from those speakers either).

I think the noise is being picked up from my RCA cables. I unplugged the antenna and the noise is still there. I then unplugged the RCAs from the amp with the engine on and no noise, when I unplug them from my headunit (and leave them plugged in on the amp) there is now noticeable noise at all speakers.

I'm running my power cable down the passenger side and my RCAs down the driver's side of the car. My RCAs are the Monster Cable 6 Channel MicroXLN, which are suppose to be good at suppressing noise.

Will changing the RCAs to a higher end twister pair design fix my noise problem? Any RCA recommendations? Could the noise be from something else other than the RCAs?

Thanks,
Michael

 

One more thing. I'm running my CD Changer Ai-net cable down the passenger side (same side as the power cable) but I don't think this is a problem since the alternator noise is still present whenever I use the in-dash cd player or the radio.

I would like to avoid spending $300+ on new RCAs if there is something else that can be done. Thanks.
Mike

 

unplug the rca's from the amp. do you still hear the noise?

 

I don't hear the noise when I unplug the RCAs from the Amp. I do hear the noise when I unplug the RCAs from the headunit.

 

Run your RCA cables away from your power cables. Put some extra shielding on them like wire loom. Also make sure that there are no power cables close to the RCA connectors at the amp.

 

You may have a grounding problem. You may have a ground loop, which is allowing the coupling of the alternator whine into your signal. Check your connections to ground, both at your amp AND your headunit - make sure they are solid and not obscured by any body paint. (Use a star washer under each grounding bolt head to cut into the surface if you haven't already done that.) Also try connecting a thick, low-resistance wire (spare hunk of 4 or 8 ga.) directly from your headunit ground to your amp ground to approximate more of a 'single-point ground'. (ALL of your equipment should optimally be grounded at one common, single point - grounding to the body is a compromise that we can usually get away with, but not always...)
You may want to try a different set of RCA cables as an experiment, but I'd work on checking out the other stuff first.