[200q20v] Re: Help needed on non-Bose (Avant) radio replacement

[Calvin & Diana Craig]

Tom,
I just got done installing a JVC deck with a Sony 4x75 watt amplifier and I
am using the factory speakers all the way around.  The reason you aren't
hearing anything when you hook up is because the remote/antenna signal from
the radio has to be transferred to the amplifier that is under the rear
seat.  Let me explain to you how the rear speakers are wired up from the amp
out to the doors.

There are two 6 pin connectors that go to the rear amp.  One connector has
the power to the amp, the remote signal, and the line level inputs (2.0
volts).  The other connector has the outputs to the speakers.  The 6 pin
connector has two rows of three pins.  each row of three pins goes to one
door.  The 3 pins are the + to the low freq. speaker, a common ground to
both the high and low, and the + to the high freq. speaker.  You can
identify which 6 pin connector it is by measuring the resistances that
should be about 4 ohms...if you measure from one positive to the other it
whould be 8 ohms since they are in series with the grounds tied together.
You can simply cut the amp out of the circuit and run your two pairs of
wires back to the 6 pin connector from the deck.  Each side can be hooked up
to one pair of wires.  On each side you should tie the - from the deck to
the common negative, the positive from the deck to the positive of the low
frequency driver, and also tie the positive through a NON POLARIZED
capacitor of about 7 to 10 microfarads to the positive of the high frequency
driver.  Determine which speaker is which by just hooking up directly to
each ones at low to moderate volume levels.  You don't want to drive the
high freq. driver without the cap. in place at high levels because the low
frequencies may harm the speaker.  The capacitor will block these from the
speaker.  Make sure you get a NON POLARIZED cap. and make sure it is at
least a 20V rating, if you ever drive more power through the speaker you
will have to go up on voltage rating, but 20V should be fine for up to 100W
or so.  Then just hook the front speakers up directly like normal.  Since
they are only 3.5 inch drivers I usually put about a 150 uF cap. in series
with them just so I can jack up the bass input to a sub without any harmful
effects, but it's not necessary under normal circumstances.

Although this presents a little less than a 4 ohm load, which I am sure is
what the deck recommends as a minimum, in my experience it doesn't hurt
anything.  At any rate, because of the natural frequency rolloffs of the
drivers, combined with the cap, it probably nver drops close to the
theoretical low of 2 ohms.  If you have any questions don't hesitate to ask.

Also, if you want your door chime to work when you open the door with your
radio on you have to wire the remote wire up to the old connector that used
to plug into the back of the radio.

--Calvin Craig
Parker, CO
'92 S4
'91 200 TQ
'89 200 TQW
'72 Formula Firebird