Sure sounds like the vehicle electrics are the cause or at least part of it
and that head unit likely ok. But to be sure....

Do you have a car radio you can hook up?

My thought: if something went slightly hinky on head unit (cap where power
goes in? Final stage amp?), and alt. etc. is supplying less than best
quality power, this might produce a sudden change.

Neil.

On Fri, Apr 1, 2011 at 5:58 PM, Alistair Bell <albell@shaw.ca> wrote:

> A  few months ago the radio in the van has developed a whine when
> engine running.
>

>
> Came on all of a sudden, and only on the front speakers which are
> powered by separate amp and go through crossovers.
>
> What I have done:
>
> -redid all grounds, signal, and power leads to front speakers,
> crossovers, and amp - no change
> -swapped in another amp - no change
> - tried alternate pair of rca jacked leads from head unit to amp,
> straight run, not crossing power lines - no change
> - new antenna and lead to head unit (old one was really bad at head
> unit) - no change
> - if i grounded amp directly to battery post instead of body, noise
> was louder. BTW, the amp ground wires are a short run twisted trio.
>
> Recently the noise has become louder and worse.
>
> Today I pulled the alternator and:
>
> -pulled brush pack and cleaned connections
> -pulled the noise reducing caps on alternator and cleaned connections
> -removed the diagnostic plug (TDC sensor lead and plug) from alternator
> -pulled distributor cap and cleaned, above and below black plastic
> shield
> -cleaned up edge of rotor
> -cleaned all the grounding points (pivot bolt area etc) on alt body
>
>
> these things have improved things, the whine is much quieter.
>
> Can anyone suggest anything else?
>
> thanks
>
> alistair
>

--
Neil Nicholson '81 VanaJetta 2.0 "Jaco"

http://tubaneil.googlepages.com/

http://groups.google.com/group/vanagons-with-vw-inline-4-cylinder-gas-engines