It could be the head unit, but the whine only comes through the front
speakers (external amp supplied). I could try switching outputs to amp.

New sparkplugs (NGK B6ET) didn't change things.

I have noticed the whine changing in intensity at times, not related
to engine speed. I have it in my mind that it is alternator, maybe a
hinky diode, but that's just an unsupportable guess. I'll get David B.
to fix it when he comes by tomorrow :)

alistair

On 3-Apr-11, at 9:36 AM, neil n wrote:

> 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.