[s-cars] stereo upgrade

[Aaron Ryba]

> I have the popping but not the ground problem.  Did the ground problem come
> when you put the in line converter in?  The best ground I can find is the
> wire that goes to the original head unit...it is a very good ground.
> --Calvin

No, the problem was there before I installed the line converter.Not sure about it before new head unit since
the original head unit was code locked. Since my Alpine head unit has only 2v preamp outputs and not the 
required 4v to run the preamp/RCA/patchcords-style connections through into the line converter 
(as required by the converter) it is all speaker line-level wires from the deck to the 
converter to the factory (repaired) wiring. 

> My 200 had very bad ground loop feedback with an aftermarket head unit 
> hooked up to the Factor Bose amplifiers. The problem turned out to be that 
> I had grounded the line-level shields to the chassis ground when I 
> repaired the harness (it was butchered). Removing that ground connection 
> and using only the RCA grounds solved the problem for me. Depending on how 
> the line-level shields on your head unit are grounded, you may also need a 
> ground loop isolator.
>  	-Kurt
 Well, I was thinking the factory line-level shields might be a problem however the Bentley
wiring diagram shows that those line-level shields for both front and rear are connected
directly to the common chassis ground through wiring harness #133 which is also connected
to a ground connection wiring harness #33 behind the instrument panel along with the ground
connections for the Speaker Power Supply relay J225, 2 grounds for the head unit T8/2 & T8/8,
and the ground connections for all three amps. 

Maybe this ground connection needs a bit of repair or possibly some of these have been butchered
to be grounded independantly. From what little I know about ground noise it is caused from feedback
through multiple ground connections. 

I bought a ground loop isolator and hooked it up to the head unit power supply and nothing, noise persists. Since I
can't use the RCA preamp connectors I couldn't use a RCA style ground loop isolator like radioshack sells which
I assume goes between the head unit and the amp. This one I got is actually a power supply ground loop isolator
with an in, and out and a ground wire. I tried it with the main power supply line to the head unit, maybe I need
to try it with the ignition/accessory turn on lead to the head unit?? Or would I need one before each amp as well?
It just seems a bit odd like the factory wiring is not quite back to factory yet since not that many other people
running the same setup as me have had this problem. I would rather fix it right than bandaid patch the problem with
an isolator.

My line-level converter has a ground in and out so maybe grounding that may help!!???

>> -----Original Message-----
>> From: s-car-list-bounces at audifans.com
>> [mailto:s-car-list-bounces at audifans.com]On Behalf Of Aaron Ryba
>> Sent: Thursday, March 01, 2007 8:25 PM
>> To: s-car-list
>> Subject: Re: [s-cars] stereo upgrade
>>
>>
>> I am running a new alpine head unit to the stock amps and speakers through
>> the stock wiring using a fabricated connector.
>> The volume/gain and pop turn on problem was solved with an in-line converter
>> for about $25.
>> The problem I am having now is bad ground noise. I have tried grounding the
>> head unit directly to the chassis but no change.
>> I assume there is a bad ground in the harness somewhere for the three amps
>> in the stock "BOSE" system.
>> I had to piece back together the factory wiring since a previous owner had
>> cannibalized the stock common ground speaker wiring to use as speaker leads.
>> Has anyone had this bad ground noise problem with a new head and stock amps
>> and speakers? Maybe it is just my crapped out wiring.
>>
>> Thanks,
>> Aaron Ryba
>> 95 S6 138k






 
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