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Auxiliary Input
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The ability to have a "clean" line input
to the factory headunit is something many Saab owners have wanted for a long
time. Several have hinted at doing this, but no one has come
up with any specific details. The choices are: FM Modulator,
which gives static feedback at times and can also be more difficult
in dense (radio stations) areas; cassette adapter that gives
considerable amounts of feedback or more difficult tap its inputs;
hack the CD changer cable. The best route seems to be the
latter - hack the CD Changer cable. Also, because the Clarion
C-bus communication protocol has been replaced with newer
technology, there isn't anything worthwhile to make an Aux-in easy,
such as a purchasable adapter.
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Searching the topic brought me to several locations. The most notable was among the many Volkswagen
owners looking for the same thing - VW Switchable Aux input
The idea is to install in-line with the L/R channel inputs a switch
that allows one to choose either CD input or Auxiliary. By
doing it this way, there is no need to "hack" the C-Bus
"handshake;" a CD is attached and spinning, so the
headunit recognizes the connection. It was a result of this link that I was able to confirm my
suspicions, and muster up the courage to attempt this.
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My CD Changer was the first purchase for my Saab
since it did not have one at the time of sale: model - Clarion
ProAudio DC625. The changer came with a cable, but as most
Saab owners know, most (almost all) NG900s had the cable run from
the headunit to the boot (as was my case) regardless of whether
there was a changer attached at the other end. This spare
cable seemed to be the perfect donor to the project, so I decided to
test out this idea with the spare before I went hacking the
"good" cable. When you're ready, the CD cable
runs down the driver's side kick panel.
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With this "key" one can see that it is the
wires for L/R ch inputs that need to be tapped for the Aux-in.
However, they are a bit "hidden." They can be found wrapped up in "foil" and then
by a gray insulation. When you split open (carefully) the CD
Changer cable you will see (10) red, (5) orange, (1-4) gray (very
thick), (9) black/glossy, (3) brown, and the desired foiled-covered
L/R ch input wires. I removed probably 2-3 inches of the
covering to give me ample space to work with.
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When you isolate the covered L/R ch inputs, you can
simply snip the wires because they will be re-connected in order to
get the desired switching-effect. I actually stripped the
cover off, which allowed me to see the two wires including the
insulation. That way I could snip just the thin Green and Grey
wires without cutting the insulation. It will be apparent when
you do it.
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The basic overview is attaching the snipped end that
goes to the CD changer to one side of the double-pole, double-throw
(DPDT) switch and the end that goes to the headunit should be
attached to the middle (constant output) of the DPDT switch.
For the other side of the switch, two wires should be
connected. These will go to your RCAs and ultimately be your
auxiliary input. The "hard/tricky" part is knowing
that you need to maintain a ground to have a clean connection.
"The better the ground, the better the sound."
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I accomplished the above by soldering in wire to
extend the L/R ch inputs on both "ends." I ran wires
about two arm lengths, so perhaps several feet; it has to be enough
to get from the cable, to your switch, wherever you decide to place
the switch, and as always, I felt it was better to have too much
than not enough. I had high-end speaker wire lying around, so
that is what I used. Additional short pieces of wire was used
to connect the "ground" wire between the two maintaining
the connection that was previously there. [SEE ABOVE PIC and
BELOW PIC] An additional ground that should be the same length
as the other L/R wires needs to be connected, as this will be used
for the ground on the RCAs.
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With all of these connections made, and your wires clearly
marked (TO HU and TO CD), this "joint" can be taped up and
considered completed. The hard part is done and the only
connections left are the RCAs and to the switch.
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Separately, two wires need to be connected to RCA
inputs that I picked up from the Shack. The "line"
wire is connected to the end of the RCA plug and soldered on to
maintain the connection. In addition, a ground needs to be
connected. I chose to share the ground between the L and R
RCAs, so a short wire was connected between the two and then the
ground wire from the CD Changer cable gets soldered
here.
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Now it's a matter of connecting the six wires
properly to the DPDT switch (you do have 6 wires correct?! 8oD
) The "TO HU" should be connected to the center of
the DPDT switch; this means the connection is constant to the
headunit. Then, the other two pairs of wires (TO CD and the
newly created RCAs) are connected to the outer ends of the
switch.
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What happens is that the CD Changer is still
connected and running. Therefore, the "handshake"
that occurs when one pushes the CD button of the headunit is not
disrupted. Now, when you want to listen to the CD Changer, the
switch is positioned that way; want AUX, "flip/push" the
switch and play the MP3/DVD/etc. Easy as that. The CD
will continue to spin, so you will loose your "place," but
that's what the seek button is for, and how you get around Clarion's
(Saab's) proprietary connection; it's a trade-off. The only
downside is when the CD changes, as there will be an interrupt in
the AUX signal (quick mute). I plan to use a "blank"
80-minute disc of nothing. This will avoid any seek
issues.
sexy
leg?!
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Please be sure to fully test this prior to
"Closing" everything up. Because of the location of
my switch and soldering the connections to the back of the switch, I
had to cut the six wires and reconnect with plugs in order to feed
them through the hole I drilled for the switch. Unfortunately
I did not label correctly, and put together, pulled apart, put
together, trying to get things "working" when I know they
did work! This caused me the usual "Why doesn't it
work!!!" stress.
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The last piece is the "finishing"
touches. Where should you put your switch? Where do you
want the Aux wire coming from? I chose to use my cell phone
mount, as it is both out of the way and "stealth."
For the cable, I decided on the driver's side kick panel because I
would most likely mount my MP3 player where my old cell phone was
held, which is just off to the right of the steering wheel/top-left
of the SID/stereo.
the
switch (cell phone holder removed) 
AUX
cable coming from driver's side kick panel.
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And there you have it. Any comments are welcome, and now I do have a
spare cable I may be willing to part with. I'm not sure what it's
worth to people, but I may also be willing to make these up for a nominal
fee (no Scott, this is not intended as selling these and if enough
interest, I will take out a classified).
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Questions, Comments, Observations are of course
welcomed. Thank you to the VW sites for laying this
information out there. And of course thank you to SaabNet for
all of the additional help (outside of this)! I am happy that
I can finally contribute something original and hopefully of value
to all of the valuable members here!!!
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