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Who knows something about '89 and later stereo amp?

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Old 01-26-2010 | 05:18 PM
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Default Who knows something about '89 and later stereo amp?

I am still wrestling with what to do about my stereo system. Car ('90 gt) came to me with CD2 and no code. The system had been changed out at some point and returned to semi-stock but with an earlier model (pre '89 ) amplifier. It is evident the speaker wiring has been modified and then reconnected. The older amp has four speaker connections.
I found a used late model amp. It appears to have 6 speaker recepticles, four on one side and two on the other. Should I have 6 speaker wires to plug in? I only find four.
I finally have a line on a good CD2 with code and if I buy it I want to run it through the OE amp.
I have also considered changing to a totally different head unit (CDR220 or Nakamichi MB-VI), in which case I will have wasted the $ spent on the amp...decisions, decisions!

Last edited by Jim Chambers; 01-26-2010 at 11:09 PM.
Old 01-26-2010 | 05:23 PM
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The original amps are crap. If you can, get an aftermarket one. Even the cheapest ones are better than the OE.
can't the dealer get you the code for the locked deck?
Old 01-26-2010 | 05:34 PM
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No. After much research/2 dealers and SW Stereo, a CD 2 without a code is useless.
My problem is me.........I am by nature a "keep it original" purist. I realize a modern system will provide better sound reproduction. Fact is, I rarely listen to radio/cd's in the car anyway! Just want to have the car "right" by my definition of the word. Thanks
Old 01-26-2010 | 05:58 PM
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Jim-

I have the original amp in my '90GT, and another from a '93 GTS- I can take some pics of connections tonight and post 'em. I know they're crap, but I've got the original CD-2 for the '90 and a CR-1 and changer for the '93. Someday the 'crap' may be worth more than the latest blingy swimming dolphins headunits....

RE: the code, c'mon, there's only 7776 permutations of a 5 number code randomly ordered from 1 to 6, and you get 3 chances before it locks you out for 24 hours, right? Worse case scenario, you'll have the code in 7 years....
Old 01-26-2010 | 06:04 PM
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I thought there was a way to get the code from the numbers on the back.
Old 01-26-2010 | 06:08 PM
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Just want to have the car "right" by my definition of the word. Thanks
I fought that fight with myself for years and finally gave up.

I'm putting wrong hoses, wrong tire sizes, wrong Tb tensioners, etc on the car. At some point it's just not going to be possible so I finally gave up and went to new technology on the radio too.

I kept the old Blau and amp in a box in case I ever really want to put it back, but on this one I finally just had to give up. Frustrating for sure.
Old 01-26-2010 | 06:15 PM
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This is not a case where stock makes any sense.. all the stock amplifiers are crap, by now the speakers that werer never great have deteriorated to crap too, the head units were never really good either...

You should have a 6 channel amp and 6 channel wiring too - sounds like the wiring has been heavily modified...

If you want it to just "look stock" find some good replacement speakers (or at least refoam the originals) - keep the stock grills, find a good stock headunit and mate it to a good small modern amp that will fit in the stock location...

Complete Originality? ... ahh well - just get over it ...

Alan
Old 01-26-2010 | 06:18 PM
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Rob, I would greatly appreciate a pic or two of the installed amp on your '90. Let's see, I'm 68 so by age 75 I could have tunes! But could I hear them?

Jay, your Nakamichi install is the other option I am agonizing over. No need to use the amp (and replace my damaged head to amp cable) and at $300 it will cost the same as seller wants for a very nice CD2. And the replacement cable is another $44 at 928 Specialists! The price of being "pure". The more I type, the dumber I sound!
Old 01-26-2010 | 06:31 PM
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The price of being "pure". The more I type, the dumber I sound!
Not at all, it's just getting so difficult. If there were options that made sense I'd be all over them, but ebaying an old CD2 and hoping the code works just scared me away from that one.

Wish some of the electronic guys could find a way to work around that.
Old 01-26-2010 | 06:31 PM
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Till I get home, here's a shot of the connection schematic on the amp in my '90- looks like there are 6 speaker connections. Will reality-test and look at the actual wiring tonight.

Old 01-26-2010 | 06:39 PM
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I have the same schematic on the amp I bought. Appears there are channels for left and right woofers. That would be 5 & 6. That suggests that two of the ten speakers in the car are "woofers".
Wonder which ones.
Old 01-26-2010 | 06:57 PM
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The woofers are the bigger B-Pillar speakers. For your model year you should have 10 speakers.

The doors each have a speaker pair supplied by the Front L/R channels. Each door pair is fed from an in door crossover which splits mid-range & tweeter from bass cut channels (not much bass reproduction on the front channels).

The B-pillar woofers are on one set of rear L/R channels as essentially treble cut channels.

The other rear channel L/R pair are bass-cut channels that feed a crossover mounted on the back of the woofers (but not connected to them) that then feed the smaller B-Pillar tweeter and the rear quarter mid-range units.

The whole system has no sub-woofer capability, so really low frequency bass is just lost.

Alan
Old 01-26-2010 | 07:14 PM
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Thanks Alan. Clearly you understand the system and now I understand it a little bit. I am guessing that the PO simply wired the B pillar woofers together with the other rears at the amp. I suspect that if I go with another head unit with a 4 channel output, and delete the stock amp, I wiill need to do the same thing.
Old 01-27-2010 | 12:52 PM
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Here are shots of the amp connections on my '90:


EDIT: Schematic again:



Front-facing connections (Red to right woofer, yellow to left woofer)





And the rear-facing speaker connections:




Closeup of the 2-pin connectors:

Old 01-27-2010 | 12:57 PM
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Thank you very much Rob. Not simple pictures to take. They are exactly what I need. Now off to search for purple, green and turqoise wires. Greatly appreciated.


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