MP3 and stereo options

cowtown · 10-31-2004, 03:40 PM

(This is an addon to grmnxtc's stereo information in the "this forum needs pictures" thread).

I'd like to install MP3 capability in my '95 (with HIFI stereo option). I see the amp under the passenger seat, and I have an Alpine 6-disc changer in the front trunk, which I think was a 95-only item.

I've read on the other forum that the underseat amp takes a nonstandard signal that falls somewhere between line level and speaker level.

So if I want to replace the head unit with an MP3 capable unit, how do I wire it into the underseat amp? Or do I get rid of that amp and go direct to the speakers? If I keep the amp, where do I get a wire harness pinout?

I'm not really interested in upgrading a bunch of components because I'm happy with the sound quality. But I'm up for replacing the head unit.

Thanks,
Colin

maxnine11 · maxnine11's Garage

Colin, the amp under the seat is a Nokia (that i believe is a hollow box with a turd in it)

Any small amp from a brand name mfg. will out-perform it by a wide margin. The stock Nokia speakers suck too. I still have the stock hi-fi setup, but with a CDR-220 head unit from a 996. One day i will upgrade the speakers and amp.
We can only be thankful that we weren't the unfortunate buyer of the car new, who paid a LOT for the factory hi-fi option or DSP option, and recieved crap.

jhc · 11-01-2004, 11:55 AM

I recently took out the stock head unit from my 95 and installed an alpine 9811 cd/mp3 player.
It was a leftover '03 demo which I chose because it was $200 and black (most '04 models are silverish).
Most good head units will have the rca outs for hooking up your amp. The harness is easy to splice since the color codes are the same and my alpine fit the stock unit chassis.
This enabled me to unhook and sell the cd changer since you can fit over 100 tunes on one mp3-cd. The alpine doesn't skip at all (I've heard that the Nakamichi and some of the others skip like crazy). Also all AI-Net equipped Alpine head units can be connected directly to an ipod if you have one.
The radio reception will suck unless you know how to properly connect the antenna lead (which I haven't done yet).

cowtown · 11-01-2004, 12:03 PM

Thanks for the replies.

JHC, I can't tell from your writeup whether you have retained the stock underseat amp, bypassed it, or replaced it with a new amp.

If you retained the stock amp, did it accept the signal from the RCA outs on you new head unit?

I'm trying to figure out if what I read (about the stock amp's input signal requirements being non-standard) is true.

Thanks,
Colin

jhc · 11-01-2004, 12:41 PM

I don't have the hifi amp, but if its like any of the other stock porsche "stereo" equipment I would bypass or replace. The 50w Alpine is plenty especially since the front stock speakers are intermittant and fuzzy sounding.

grmnxtc · 11-01-2004, 02:33 PM

Colin,

Here's some extra info that I hope proves useful.

Firstly, I stayed with the original Amp as

1) I couldn't find anything to replace the Nokia 6-channel underseat Amp that fitted in such a tight spot and
2) I don't need a perfect acoustic environment with the top down and
3) I didn't need to spend a fortune on megawatt woofer amps and "bling-bling" that appears to be all the rage nowadays. (yep, call me an old fart that values his hearing)

That said, here's some info on the wiring that might help.

When replacing the head unit, I found the harness already had connections that matched the Blaunpunkt MP34 I wanted to fit. Note however that the PO had an Alpine CD player installed, but the wiring harness looked original.

Here's the connectivity that I had (taken from Blaupunkt manual)

The wiring is, I believe, according to DIN standards (Germans are great about standards!)

Then I figured out the wiring to the amp itself (my car has the Hi-FI option fitted) which is here (this info is not in the service manual wiring diagrams):

The other connector (long an thin) on the Amp goes to the speakers themselves. I have the wiring details at home and will post back later.

Hope that helps you or someone else.

Clive.

cowtown · 11-01-2004, 07:18 PM

Wow! Thanks for posting all that, Clive. That is very valuable information that will save hours of multimeter testing.

I guess I'm just not really that picky a listener, since the stock system sounds decent to me. I think I'll ease into things and just start by replacing the head unit. Then later I'll put a different amp in if needed.

Thanks,
Colin

plain fan · 11-02-2004, 07:04 AM

I thought I would mention that many head units sold today have the ability to increase the sound level as the noise level increases.

grmnxtc · 11-02-2004, 09:22 AM

Here's the follow up I'd promised regarding the Amp connectivity.

Code:

Pin#	Wirecolor		Function

5	Brown			Power GND
6	Brown			Power GND
10	Red			Power +12V
11	Red			Power +12V
13	White/Red		Speedo signal

7	Shielded Blue/Black 	Gnd for DSP controller
8	Shielded Blue/Red	Data for DSP controller
9	Shielded Blue/Yellow	Clock for DSP controller

16	Brown/Green		Front Left Woofer -
17	Green			Front Left Woofer +
24	Brown/White		Front Left Mid/Tweeter -
25	White			Front Left Mid/Tweeter +

19	Brown/Yellow		Rear Left -
18	Yellow			Rear Left +

20	Red			Rear Right +
21	Brown/Red		Rear Right -

23	Black			Front Right Mid/Tweeter +
22	Brown/Black		Front Right Mid/Tweeter -
15	Violet			Front Right Woofer +
14	Brown/Violet		Front Right Woofer -

The pin numbers are taken from the Service Manual wiring diagram for the 95/2 model (sheet 9).

Perform your own sanity check before re-wiring anything!

Hope that helps!

Clive.

bigbris1 · 11-17-2004, 06:27 AM

I have a Nakamichi Musicbank75 for sale inperfect working condition. For those of you who are unfamiliar w/the MB75 it's a standard size DIN headunit with integrated 6 CD changer. That's right, 6 CD's in one regular sized receiver.

For more info look on the Nak website at www.nakamichi.com & click on Musicbank CD changers.

Comes with remote, all wiring, amplifier, owner's manual, RCA filter/adapter, bezel & case to put removable face in.

I'm asking $250 shipped to 48 states.

This is only available today, email me at bigbris1@msn.com

Thanks!

cowtown · 10:27 AM

Just a followup - maybe this information will help someone in the future.

I ended up replacing the factory-installed Alpine 6-disc CD changer with an Alpine CHA-S634. This is a 6-disc changer with the same form factor, but it also plays MP3 discs. It uses "Ai-Net" to talk to modern head units, but can also interface with the Porsche CR-1, which is a rebadged Alpine unit.

The CR-1 uses an older communication method called "M-Bus". There is a switch inside the CHA-S634 that turns this older mode on. With an adapter cable (part #KCA-130B), the new changer plugs right in to the Porsche head unit.

The end result is an otherwise completely stock system that plays 6 discs of MP3s.

Now I'm looking at speakers and amps, but this CD changer seemed to be a good way to get started.

plain fan · 12-08-2004, 07:49 AM

Colin,
For fun take the average file size of one of your MP3s then divide it into the space provided on 1 single layer DVD disc. Then multiply that number by the length of the file you used in the original calculation...

Thanks for posting the Alpine disc changer number; so far I've only seen a Sony 6 disc changer listed as MP3 compatible.

autoxracer31 · 12-08-2004, 05:51 PM

mp3, get an alpine deck that plays mp3 cds (200 or more)

OR

get an ipod (200ish depending) and the transmitter (30$)

The Ipod transmitter broadcasts i think a 6 foot range on FM on 87.7 whatever your ipod has selected.

Tom W · Tom W's Garage

An iPod and the Alpine adapter for your head unit will eliminate the need for a changer completely. For a few hundred you can get a new/better head unit, $140 for the iPod adapter (and then you need the iPod if you don't have one). The few thousand songs on the iPod ensure you always have what you want to hear (and don't have to worry about changing disks). The head unit will still play music CDs if you want (or MP3 CDs).

Rob Channell · 01-16-2005, 04:46 PM

Grady,

OK, I bit. I can fit a LOT of MP3's onto a DVD disk. Who makes a head unit that will read DVD and CD formats containing MP3s?

plain fan · 01-16-2005, 08:36 PM

Rob, I think the upper end, fold out, widescreen systems designed to run a car theater can read MP3 on the DVD disc. The real limiting factor is how poorly thought out the MP3 file system is on burned discs. You can only have 8 directories, which to me makes no sense what so ever.
I'll look around and see what I can find. You would probably wind up spending near 1K just for the head unit.

Rob Channell · 01-17-2005, 04:20 PM

Thanks for the info. Only 8 directories? Yuch. I have mine organized by group name, then album, then songs. I want more than 8 albums. Hard drives rule for cheap mass storage.

Sounds like an in-car PC would be a better deal possibly. Then you could add data acquisition/ a GPS interface and software, and a host of other stuff.

plain fan · 07:03 PM

Kenwood and Rockford Fosgate offered a removable hard drive music jukebox for awhile. It looked like the size of a laptop drive that plugged into the base unit in the vehicle. It even went as far as offereing a wireless unit to allow you to transfer files from your house to your car. Unfortunately it was priced well above what the market would sustain and it arrived right around the time mp3 started to take off. If I still had the links I'd send you to a site devoted to running computers in vehicles. That is true media availability.

I did a quick search on Crutchfield and came up with these:
http://www.crutchfield.com/S-d58TeQKTbcf/cgi-bin/ProdGroup.asp?g=50800&avf=N

Not the site I remember but a start:
http://www.mp3car.com/