6ta1

hi,

I have an 04 996 with the cdr23 and MOST system with the bose amp in the front trunk.

My car has a lot of weight out (~150lbs) and I was planning to remove the amp and connect directly the front speakers to the cdr23.

issue is, although the cdr23 has a standard ISO speaker plug, there is no signal going to it right now. I am assuming that the internal amp is de-activated to use instead the bose amp

is it something that would have to be changed by the dealer using PIWIS?
Like tell the car that there is no more bose amp and that the internal amp of the head unit should be activated?

I guess this is a fairly rare issue since most people would just upgrade the head unit, but I cannot find any after market head unit that would look OEM in the 911.

Any ideas?

jeneric996

You can simply unplug the Bose subs at the box. There is a connector and wire behind the box. You'll save about 13 pounds.

The amp will be harder:

Remove amp and unplug at connector.

Recommend buying a factory Bose harness for a easier plug-n-play.

I think you'll have to run speaker wires from the head unit to the connector. Find the leads at Bose amp connector to the dash and rear quarter panel speakers. These run at around 4 ohms each.

6ta1

thanks, but your missing my point.

the issue I have is that the speaker plug at the back of the head unit get no signal, and I am assuming this is because the head unit is expecting the most amp.

so my question is: how do I make the head unit work without the most amp

jeneric996

Oh.

I think you'll have to replace the headunit because of the fiber optic wire the goes between the headunit and amp. I think the two are dependent on each other; this was one reason these units didn't need a security code.

During my research, Nakamichi headunits were the closest ones that look stock.

pfbz

Not sure, but my guess is that the internal amp on the CDR doesn't require any additional enabling... Perhaps you need to remove the optical cable to switch on output on the Becker?

Security code is a separate issue, though I think the radio is 'activated' not through the fiber cable but rather through one of the other wires going from the radio to the PCM module. Again, easy to check... Disconnect the fiber line from either the radio or amp and see if the radio wakes up and gets past the 'Porsche" display, even though you obviously will have no sound.

Yet another issue might be speaker impedance... I believe the Bose system uses some funky low impedance speakers in different locations. They might be too low impedance to drive with the CDR23 directly and you might need to replace them, plus they might just sound terrible without the typical Bose mega-equalization.

For best sound, lowest weight, least hassle, a replacement aftermarket radio and four replacement speakers is probably the way to go.

If you really want the full OEM look and can't get your radio to work with the internal amps or security issues, you could buy a pre-MOST Becker radio on ebay or here: http://www.beckerautosound.com/plug_...e%20index.html

I went with an aftermarket Pioneer unit (DEH-X9500BHS, install details here) It's a great stereo for little $$ and it at least allows me to color-match the buttons and display to the Porsche color. I also needed some Bluetooth and USB features that I wasn't going to get with any Becker.

Obviously I have more going on here than just a simple radio swap, but this at least shows the Pioneer in situ.

pfbz

By the way, here's a wiring diagram of the CDR in case its helpful... I think it is Pin C6 or C1/C2 (can-bus) that communicates radio the security code to the PCM, not the fiber cable, but not 100% sure.

pfbz

And more CDR23 documentation...

6ta1

thanks for the good info

you are correct, the "code" comes from the smal yellow plug. Radio turns on just fine without the fiber optic connected

good point. I had not really thought about that. I think the dash and door speakers are 2 ohms put in serie so that will be an issue. I had planned to put 6.5" in the doors but I will have to change also the dash speakers. The idea is to connect the dash speakers to the front output and the door speakers to the rear output of the head unit (rear speakers are out for a long time now)

yes, my dream is to find a cd-less head unit that would match the interior. (cd-less means less weight :-))

yes but... way too expensive and I want usb

not bad, still wish it was matte black instead of shiny, but that's the idea

this is a good idea. I will try

Zapna

My understanding is that there is no amplifier in the CDR-23, even though there are pins on the back of the unit, just like there are pins for an aux in that isn't enabled and cannot be. You can call Becker though and easily confirm. The Bose speakers are 2 ohms and powering them from an integrated (amp) head unit is impractical. They will have to be changed.

I really like pfbz's installation, other than the shiny look of the radio and the silver ****. I was considering using an iPad anti-glare protective screen and cut out pieces to fit over the shiny clear plastic bits and coat the **** with plasti dip. pfbz, do you have an opinion on how practical that is with that head unit? Its hard to tell from the pics and I haven't had time to try to track one down in person.

6ta1

ok, that would be a bad news.

the clarion fz150 would look OEM if it had the option for orange lights