When I re-wired the rear speakers on Dixie, in conjunction with a sub and
amp under the back seat etc, I just pulled a set of higher quality wires
down through the floor, along the tunnel and up through the back of the
closet.

I think I drilled only one new hole to get into the closet from below.  And
I didn't have to dismantle the interior.   :)

On 7/14/07, David Kao <dtkao0205@yahoo.com> wrote:
>
> Mark:
>
> There are two types of power amplifiers among car stereos. One has single
> ended
> output, the other has differential output. Single ended has one hot wire
> and
> a grounded one that is truly grounded to the metal chassis. For the
> differential
> type both wires are hot and never grounded. When the signal in one swings
> positively the other will swing negatively. It's like push pulling.
> It is capable of much higher power output. But you can not share a common
> grounded wire. Each channel (left and right, and front and rear) has to
> have
> its own pair of wiring. Never ground (connect to metal chassis) any of the
> two wires. That will cause damage to the power amplifier of the stereo.
> The power transistors will burn out almost instantly.
>
> David
>
>
>
> --- Mark Hersh <markhersh@MSN.COM> wrote:
>
> > The internal debate on the engine swap (Subie or diesel?) has reached an
> > impasse so it seemed time to do make progress with a few little
> > improvements.  Some PO had removed the rear closets, and we were able to
> > acquire those last year.  "Monty" had AC originally but the hoses had
> been
> > hacked off in the engine compartment and of course with no closets the
> > evaporator(?) was missing.  The closet we found had no AC component
> which
> > was just as well, but had the rear stereo speakers. (remaining AC stuff
> has
> > been removed except for the condenser).
> >
> > Today I removed the in-dash stereo and found four unused wires whose
> colors
> > matched up with the wires hanging out of back end of the AC duct (the
> one
> > above the slding door) and sure enough, a continuity check reveals they
> are
> > the same.  Great!  Right and left and ground.
> >
> > According to Bentley and my continuity check, the ground for those
> speakers
> > is a common ground, that is, the two wires (left and right ground) under
> > the dash must be spliced together somewhere and only one wire is run
> > through the duct to the back shelf, where a branch runs off for the left
> > rear speaker ground.
> >
> > The problem is that the stereo install/operation guide (PO supplied at
> > purchase) specifically warns against using a common ground for speakers
> and
> > says that each speaker must be hooked up to the ground wire coming out
> of
> > the plug/harness/birdsnest coming from the back of the stereo.
> >
> > I pulled off one of the vents and the front end of the duct work (just
> > above and behind front passenger seat) and see the wire bundle heading
> into
> > the mysterious region above the headliner.  Or is that just a detour
> before
> > it heads down the pillar between the passenger door and sliding door?  I
> > don't think so because I looked in some vent and also a rubber plug and
> saw
> > no wire bundle.  I didn't get underneath.
> >
> > First, I know nothing about car stereos.  WHat would happen if I
> commonly
> > grounded the rear speakers as did VW in 1986?  Blow up the stereo or
> > speakers, I imagine is the worst that could happen.
> >
> > Second, how in blazes do I get a single strand of 18-20 gauge wire back
> > there?  It wouldn't be too much trouble to get to the front end of the
> AC
> > duct, but then between the headliner and the metal... and how down to
> the
> > under-dash?  Does that bundle run down the passenger side
> windshield/door
> > pillar?
> >
> > Any suggestions/help appreciated.
> >
> > Mark
> >
>
>
>
>
>
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--
Jake
1984 Vanagon GL
1986 Westy Weekender "Dixie"
www.crescentbeachguitar.com