Please Please someone help

[Jonny Hogan]

Could you give me your advice on the following ?

I'm experiancing the dreaded alternator whine through my speakers (i'm using

infinity components up front and back and a sub in the boot of my E36 M3

Convertible - i have a

dedicate alpine amp for the comp's and JBL mono amp for the sub).

I've tried a number of diagnostics to get rid; changing power supply,

checking and double checking all wiring ets but the noise persists. There is

absolutely no noise when the car's engine is turned off. I would say that my

alternator has always been noisy though and i've noticed that the whineing

noise increases markedly when i switch on my headlights etc is there

anything that this particularly points to?. Could it be that me alternator

itself is actually causing the noise and is faulty and or on the way out

(i'm not having any problems with flat batteries though)?

Your advice would be most, most appreciarted as my beloved car's in bits

again //content.invisioncic.com/y282845/emoticons/frown.gif.a3531fa0534503350665a1e957861287.gif

Jonathan

Click to read more...

 

[gl0ck 10+ year member]

Rca Filters?

 

[crow 10+ year member]

Try running each amp individually to see if you can isolate the problem. Check the ground connections from the amps to the chassis to be sure it is attached to clean bare metal. If it is hooked to a seat belt bolt or some similar spot or there is paint on the area you grounded to you may not be getting a good connection. Check the ground to the head unit as well. You could also try running a different set of RCA cables to see if there is a problem there.

As glOck said, you can also try a ground loop isolator. I've tried one before with kind of mixed results. They are fairly cheap though so it might be worth a shot.

http://www.crutchfield.com/S-7M1DRA5f30w/cgi-bin/ProdView.asp?g=181150&I=127SNI1

Good luck! Noise in the system is a drag.

 

[Jonny Hogan]

Crow, thanks for your response. I've tried running the amps seperately but they're both making a noise - the noise always increases markedly when i connect the second amp!

I've heard that it's worth trying seperate phono cables so will give this a crack and see where it takes. What exactly is the situation with grounding the head unit though?

It's really so frustrating - i took time off work to do the thing right and dilligently ran new speaker cable to each of the 4 coponents and back to the amps using the best connectors i could afford. All the Phonos and ground and power cables are qulaity items too so i must be missing something somewhere !!!! The strangest thing is when i origionaly connected the system up to see if it was all working ok everything was fine, it was only when i put it all back in properly that the noise started.

if you could give me your thoughts on these points also i'd reallly appreciate it = thanks ahain mate - J

 

[jmanpc 5,000+ posts]

http://www.caraudio.com/forum/showthread.php?t=198477

 

[crow 10+ year member]

The link above has just about everything to look for. Another link to check into for all types of car audio info is http://www.bcae1.com/

If the ground for the head unit isn't solid, it could be the source of the noise, which is then being amplified down the line.

I mentioned the ground for the head unit from my own experience with my last truck. It came with a factory head unit that I later discovered was wired using whatever pieces of scrap wire they found lying around the shop. I recall the power wire consisted of several 12" sections of wire spliced together, some black, some red. //content.invisioncic.com/y282845/emoticons/mad.gif.c18f003ab0ef8a0d9c27ca78d77a6392.gif

You just never know what corners were cut unless you do the install yourself. It might not be the source of the noise, but it is worth checking out.