[jpk]

My recently acquired '94 has the Porsche cassette stereo and the hi-fi sound option. I'm planning on replacing the head unit with something that'll play CD's, likely a Becker Monterey or the Porsche labeled CDR-210 if I can find one.



I was hoping somebody could explain the amplifier and speaker setup for me. As I understand, there are a couple of amps, one under each seat. Do these handle all of the speakers, or is something driven off the amps in the head unit itself?

Do the amps require a line level signal (RCA or more likely a DIN connector)



Any help or suggestions will be appreciated. TIA.

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[flash]

what you have realy depends on which speaker setup you have now - there are 3 different ones for the hardtop, and 2 for the cab



how many speakers do you have? 6,8 or 10?



6 speaker setup uses no amps - 8 uses 1 and 10 uses 2



however, the amps (if you even have them) are hardwired in, not RCA, so no easy integration

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[Mark]

[quote name='jpk' date='Jun 27 2006, 10:01 AM']My recently acquired '94 has the Porsche cassette stereo and the hi-fi sound option. I'm planning on replacing the head unit with something that'll play CD's, likely a Becker Monterey or the Porsche labeled CDR-210 if I can find one.



I was hoping somebody could explain the amplifier and speaker setup for me. As I understand, there are a couple of amps, one under each seat. Do these handle all of the speakers, or is something driven off the amps in the head unit itself?

Do the amps require a line level signal (RCA or more likely a DIN connector)



Any help or suggestions will be appreciated. TIA.

[right][post="23371"]<{POST_SNAPBACK}>[/post][/right][/quote]



I may have a cdr-210 available, I am in the same boat as you and bought one but have not decided whether I will install it or not. I am guessing not and will make up my mind in a few days.

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[jpk]

OK, I think I answered my own questions. I found the wiring diagrams for the radio. I have the 490 option with 10 speakers.



It looks like the rear speakers have amplifiers built in, and the door speakers are driven off the amp under the right seat. It doesn't show a second amplifier.



It also looks like everything gets a high level (speaker level) signal from the head unit. I'm guessing that one of the Becker units or the CDR-210 should plug right in.



Does anyone know what model in-dash CD player was avaliable in the 968?

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[mitch968]

My '92 968 had the Porsche CD-2 (made by Alpine), which is a single CD/AM/FM head unit. I replaced it due to a lost security code and the CD player no longer works. I still have it in hopes of repairing one day, but most likely that'll never happen.

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[flash]

ok - i just looked at the diagram - sheet 9



i see one booster amp, though it is labeled "right" - very odd - appears to be a goofy daisy chain wiring scheme, because only wires to the right channels go to it, but then spires go from one rear speaker to the other



odd

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[jpk]

That's what I was looking at also. The lines coming in to the top of the radio are the power leads. The connections on the left side are the antenna signal and a DIN connector for the CD-changer. From the bottom, on the left side are the outputs that run straight to the rear speakers, both left and right. The connections to the right are the front speaker signals that go to the box labeled "booster right".



Notice that power leads run to each of the rear speakers (follow the lines coming out of pins 30 and 31 at the top of the radio) The red line that comes in to the radio at pin 30 is carrying power from fuse #39 in the central electric (fuse box). It branches 3 ways at the box with the number 1 in it. The other line (pin 31 at the top of the radio) splits off at a junction marker #316 and goes to ground point 2. This also continues down parallel to the power lead, splits at junction #2, and both of these go off to each of the rear speakers and the booster amp.



Notice also the amplifier symbol on each of the rear speakers.



The only wires common to the booster amp and both rear speakers are the power leads and the wire coming out of pin S on the radio (bottom center) That's likely a power on signal to turn on the other amps.



The leads going from the radio to the booster amp are labeled S, FR (front right) and FL (front left). The leads going directly to the rear speakers are RL (rear left) FL GROUND (looks to be a common signal ground - it's dotted over to the booster amp also) and RR (right rear)



I've been looking for specs on the OEM radio units themselves without much luck. Looks like they were made by Alpine. The question remains as to the level of the signal comming out of the radios - wether it's a line or high level output. If I had to guess, I'd say these were line level outputs, with thier own connector plug (red)on the back of the radio. There looks to be a seperate plug (brown) for the speaker level outputs (looking at the diagram for the radio without the M490. option). I guess it's time to pull the radio to find out what they look like from the back...

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[Darryl]

jpk - I share your frustration when trying to read the schematic! When I purchased my car, it had an aftermarket Alpine cassette head unit with a 6 disc changer in one of the rear cubbies (I found that later <img src="/forum/images/smilies/968/mellow.gif" class="smilie" alt="" /> ) I wasn't sure if I had the amps or not but figured I must based on the option code(s) but I wasn't up for taking the seats out just to satisfy my curiosity. I now know there is an amp under my passenger seat but can't seem to find one under the driver's. I also have the 8 way power driver's seat with heat, so it is very cramped under there. Perhaps it is a four channel amp and we only have 1?



At any rate, the molex connector with the red and brown wires going to pins 30 and 31 is easy to find and IIRC, there are two reds that share that connection point and go who knows where. They must power the amps from those leads.



With regards to line level or speaker level, I would have to guess it's line level BUT when I connected the new CD based Alpine, I found all the correct colors of speaker wires right there waiting for me and never had to mess with any of the amp connections or get at them for any reason. They just seem to be there and work! The schematic does not appear to show any type of audio signal from the head unit to the amp!



Perhaps the PO or the install place that did the Alpine cassette added some sort of plug and play wiring harness/adapter from the factory setup, but my new setup was pretty easy to interface. All of the colors matched this schematic perfectly. I replaced all of the speakers and the head unit and all is well. Hope that helps even a little!



- Darryl

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