update on alternator noise over speakers

[Frank de Kat]

>Message: 1
>From: "Tim Sidders" <tpsidders1 at netzero.net>
>To: "Roa, Greg" <groa at Cinergy.com>, "quattro list" <quattro at audifans.com>
>Subject: Re: update on alternator noise over speakers
>Date: Fri, 8 Dec 2000 09:49:07 -0800
>
>
>I have disconnected the RCA's, and the noise goes away....These are $40.00
>Rockford Fosgate cables which are supposed to be very good. I guess this is
>telling me that the problem lies in the RCA's, maybe if I move the remote
>turn-on so it doesn't run along the RCA's this may solve my problem.....

Before you throw out you shielded cables, you may want to try this..
Move the head's ground to be at the SAME PLACE as the amps's ground, and of
course, make sure they are both good.
WHen you do this, make sure that the head has no additional grounds through
it case or anything. (Hard to do, if mounting in something that has metal
that touches the head around the mounting hole!) You may have to pull out
the antenna from the head unit too, to test this, at the antenna cable
usually goes to ground at the body end of the antenna cable...
 
What can be happening is that the grounds are not electically at exactly
the same potential. (A SMALL voltage difference can exist between the
grounds. Small, but significant!). 
The amp sees this small voltage diffence as 'signal', along with the proper
signal, and amplifies it. If you disconnect the RCA, both the signal & the
'ground' problem go away, because there is now no input to the amp.

You could test easily enough, by disconnecting the head's present ground,
and run a long wire cross country to where the amp ground is, and connect.
If it fixes the problem, install it properly. If it does not work, you've
not wasted much time.

Regards,

Frank de Kat 
fdekat at sentex.net   
Dundas, Ontario, Canada

Audi 4000CSq (x2 !)
http://www.sentex.net/~fdekat
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