Shield on or off makes no diff. to my problem. My noise comes through
all inputs.

David... I looked at the diagram you sent. I noticed that power,
signal, and chassis grounds were isolated from each other by caps.
Seeing as I can power ground my head unit via the antenna ground, I'd
say something is different in my situation :)

having amp ground and power, and headunit ground and power at the same
spots makes no difference. grounding amp to battery directly (not car
chassis) makes noise louder.

I'm fed up with this problem. I'm going to work on something a bit
more satisfying :)

alistair

On 13-Apr-11, at 5:20 PM, David Beierl wrote:

> At 07:49 PM 4/13/2011, Richard Koerner wrote:
>> Hmm-mm, my 85 has the grounded "can" around the distributor,
>> too.  Makes it very difficult to remove/replace distributor
>> cap...annoying...I have fought with it for several minutes rather
>> than easy snap off, snap on.  I replaced my radio with a newer one
>> from a Honda Civic; maybe that radio has better filtering and
>> suppression than the original radio so that I can delete the
>> can....will give it a try anyway.
>
> If you don't listen to AM it won't make the slightest difference.  If
> you do -- try it out.  It certainly is a nuisance.  As to the better
> filtering etc...see if you can find an antenna trimmer.  If you do,
> set the radio to an empty spot or a very weak station around 1400 kHz
> and trim for loudest.  If you don't, don't expect any more attention
> to filtering than to antenna trim.  If there's a trimmer it may be
> labeled Ant Trim -->  or not at all; it may be a very small hole with
> a tiny screwhead deep inside or it may be a biggish pan-head screw
> that clearly pinches a couple leaves together as you tighten it.  The
> flat one will be near the antenna jack; the other might conceivably
> be a hole in the front panel (but there won't be one...).
>
> Yrs,
> d