Thank you so much for taking the time to document this so clearly. I have seen bits and pieces here on the forums, but you have really put it all together. As for the HU, I doubt you will get much better sound out of the Nak, since at that point, it will be limited by the capabilities of the Bose Amp and speakers. I would think the Alpine would give you great sound.

Thanks again! :thumbsup:

 

Thanks for the post..

Thanks for the post, since I will be changing out head units on my '95 S500, a little bored and to add system Bluetooth.

I ordered the Eclipse CD7200, which has 8V pre-out, and built-in full Bluetooth (rather than wiring a system add-on module), a slick USB interface (you do have to add a iPod module for full iPod usability, then wierd ass equalization )Alpine's new mic system much better) etc..

So trade off's, but still the deck with full Bluetooth system functionality is under $400.

You can shop the harness and accessories on-line, ABT offers Metra accessories at sharp prices including prepaid US Mail.. the harness was $12, antenna converter like $8, and a good ground loop isolator I picked up from another website for $12 (and its a gold plated $30 upgrade model)..so like $32-$35 bucks for the all the adapters..

 

Glad I could post something meaningful!

Just going to 4V preamp or higher would almost be a requirement. I can turn my Alpine volume to max with clean music and it gets very loud but doesn't clip or distort. I think it has more room to go higher. It is sounding very good to my ears this morning. XM is also improved since I am going from a tape adapter to AUX in. I noticed better channel separation and overall fidelity with music.

A couple of notes: the aftermarket HU will require you hooking up the amp turn on wire instead of the antenna power wire since the stock system requires both. The stock wire allows the antenna to go up AND power up the amp. If you hook the ant. wire only, then the Bose amp will power only during radio operation, not CD or other music sources.

I may shop around for those pieces on line and save since Fry's has a liberal return policy...

 

job nicely done! thank you for taking the time to share. This is now on my to-do list.

 

Something to consider and at this point I do not have any drawn conclusions about the swap:
Excellent BOSE Info

 

I read that about the way the Bose system is designed. For the most part I agree with the amount of time they spend integrating the Bose technology into our cars and how it would be difficult to improve upon that sound. However, the stock tuner is a total piece of crap, IMHO. The CD player sounds fairly good for most of the music I play. This upgrade to the HU, would probably fill out the rest of the system and provide some cool features (BT, USB, iPod). I will see if I can find the specs for the tuner, but I remember them being quite poor, very low S/N ratio and weak freq response.

 

Hi
Thanks to share your Radio change experience,i realy enjoyed this post , infact i have already order'd all the Parts you mentioned here , In Australia all those Parts cost together 143 AU$ .
2 X SNI-1 = $60.00
1 X AD010 = $ 8.00
1 X 70-1786 = $75.00
Total $143.00
All these are at
Digital Logistics Group Limited - specialist importers and distributors of quality Audio and Consumer Electronics products

for anyone here in Australia .
Thanks again MOS500

 

Hey, i am about to install Pioneer DEH-P6900UB and I got all the parts.
I just realized that i need 2 Ground Loop Isolators.
Frys ran out of Metra 40-VW12, and got myself VW10. is this OK ?

Let me know.. thank you and can't wait to finally have radio again ... mp3 playing with 11 bose speakers..

 

Wow excellent write up.

I bought my car with an Alpine deck installed, factory bose amp and speakers are still there, amp has a repair sticker for full rebuild on 06.

Stereo worked fine this morning, polished the car washed etc and now there is no sound from the front speakers at all and the rears put out a tiny bit when turned all the way up, front speakers don't even hiss slightly like the rears do when the amp/system is on. There is a very very faint sound from the fronts when turend up all the way.

So front, almost no sound at all, rear has a little bit more and do their little pop when the systen is turned on, like all the speakers normally do, fader wheel does nothing now in this condition. What did I do? all of the sudden?

 

Amp may be going bad again. When mine went bad, it hissed popped and squealed. More so when it was wet out? Yeah, what the????
You didn't mess with any wiring so I don't know, has to be an electronic malfuntion somewhere. Pull the deck and look for loose conections.
Yours being a 93 does not have a wire harness adaptor available. I think starting in 95 you can get them since the Becker was gone then. You have to cut into the radio harness to get it to work.
Start there and make sure all is still connected properly.

 

Everything is properly connected, front and back. Pulled fader wheel, no change when removed from circuit. Opened the amp too, no smells or burns, What I don't get is that the entire system was perfect but just a few hours before, then after removing the last bit of wax, cleaned up got in the car, bam, the whole system was dead. Being that there is still signal going to the rear speakers a slight bit proves the wiring for the L/R feed is not compromised. Both relays in the amp click when system is powered on. Car was not left on during the polish/wax session.

The thing is that really makes me say WTF is that usually, well in my case, when an analog system like this goes bad it will usually give warning, I had no such thing, no hissing or poping what so ever, actually the system was great, just recently replaced the blown center fill speaker and really got the full sound. It just seems to get only three or so years out of an amp that was fully rebuilt is garbage. I see where the repairs were made and such, each of the 7 channel boards was removed and labeled. The Richardson, Texas place did the work.







I made a recording in the cabin, the existing bass is heavy naturally, hopefully this helps me to decribe.

http://www.supload.com/listen?s=XR6Ydn

 

Maybe the head unit is on the fritz! If you have one laying around, wire that up and see if that may be it. Being your using the Bose amp, the signal still goes thru the tuner in the trunk. Maybe that's a problem??
If none of the above turns out, bypass all that and install a seperate amp like I did and run it thru the factory speakers. IMO - the best way to go. I bought my 6 channel Infinity for about $90 used and it blows the factory Bose amp away!! Wnat to upgrade amp to an older A/D/S someday but for now I am 110% happy with it......could use different subs though.

http://www.benzworld.org/forums/w140-s-class/1385821-rear-bose-amp-integration-adapter-w140-7.html

 

Looks like that's the way to go.
The tuner box is not there in my car anymore, the bose amp has been rigged to turn on with the remote lead then accept a simple 2 channel L/R line signal. I just wish I wouldn't have to loose my center fill, but you said an 8 ch amp would allow for a full setup right?

The headunit is fine I hooked up a few more sources into the line signal with the same results. It's an alpine unit, maybe 2-3 years old, and good one at that.

My biggest reservation is cutting anything in the stock wiring, so I would need the pins for the bose conector to apply to the output of the new amp.
And of course that amp needs to be very configurable.
High and Low pass, and selectable frequencies in order to get a good sound from around the cabin, and for it to deal with odd BOSE impedances.

It makes sense, I could pay 200USD to have the amp repaired again with no assurance it would last, or spend that or less and get a far more reliable and powerful amp, with option to expand that system thereafter, with perhaps surround sound, or dash speakers in the telephone speaker pots by the windsheild. Now just to find that pinout diagram for the older bose/becker plug.

Hey thanks BTW.

 

Unplug the main connector from the amp and here is the pin configuration:

1 Circuit 30, F4-16
2 Ground (W6)
3 Right rear speaker (H4/8) (-)
4 Left rear speaker (H4/7) (-)
5 Right rear door speaker (H4/4) (-)
6 Left rear door speaker (H4/3) (-)
7 Right front door speaker group (H4/2) (-)
8 Left front door speaker group (H411) (-)
9 Right NF signal (+) from A213
10 Circuit 30, F4-16
11 Ground (W6)
12 Right rear speaker (H4/8) (+)
13 Left rear speaker (H4/7) (+)
14 Right rear door speaker (H4/4) (-)
15 Left rear door speaker (H4/3) (+)
16 Right front door speaker group (H4/2) (+)
17 Left front door speaker group (H4/1) (+)
18 Left NF signal (-) from A2/3
19 Control voltage from A2/3
20 Fader switch (R26) (-)
21 Fader switch (R26) (+)
22 Fader switch (R26)
23 -
24 Right NF signal (-) from A2/3
25 Center fill tweeter speaker (H4/11) (-)
26 Center fill tweeter speaker (H4/11) (+)
27 Left NF signal (+) from A2/3

I bought some spade electrical connectors and pressed them into the slots on the plug as can be seen in the pic in the other thread, then ran them to the amp.
Actually didn't sound bad with the center tweeter gone. Couldn't really tell. But look for a set of low ohm tweeters. I chose MB Quart cuz of their soft highs and I think they are like 6 ohm or something goofy. The phone speaker location would work great.
My amp is in bridged mode @ 2ohm to work well with the low ohm Bose and has worked fine.
As far as 6 to 8 channel amp about the only ones to find are Infinity, Memphis, older A/D/S & JL Audio. The 8's are hard to come by and when you find them expect to pay about $400 min. used.

 

That, is wonderful info, thanks!

I decided that I'll simply run two 4ch amps, much lower cost but still appropriate for the application. Once this is done, I'll take pics and post it up.

 

remove aftermarket head unit

Hey! I had Circuit City install the Jensen UV8 unit into my 98 slk 230. They overcharged and wanted an extra $50 to plug in 1 extra wire to connect MP3 players. I thought this was ridiculous so I held off but now I want a go at it. Can someone please tell me how to release the aftermarket radio so I can get to the back and plug this one A/V cable in? Thanks!

 

I don't have a lot to add to this thread, except that I've just replaced the Bose head unit with a Sony, Model MEX-BT3700U. I have a portable GPS, and I've no need to play DVD's, so I decided to go with this model for its bluetooth, front USB port, compatibility with iPod and iPhone.
I read the comments above, the pictures were great, but I had another problem. The previous owner chose to remove the phone unit, and cut off the cables near the rear of its compartment on the dash.
I removed the compartment to try and figure out if it was going to be possible to reuse the built-in microphone and avoid running the cable for a new one. After a couple hours with no success snaking a cable from the dash to the rear of the head unit, I decided to remove the glove box, and found a way to get the cable through, plus, i found the existing mic cable behind the glove box. I pulled the mic cable so its end was more reachable and attached a new cable to its cut end, and plugged the other end in the new head unit. I connected the rest of the cables to the new unit, was able to pair my iPhone, stream stereo music through bluetooth, and I made a phone call, and the built-in mic worked great!

I used it for about 5 hours straight today, listening to music and a few phone calls, and even got some highway directions with the iPhone without having to plug it in to the USB port to charge it.
The unit was 200.00 US dollars, came with a wiring harness to plug it in to my Mercedes, and everything I needed except a bunch of small wire crimps I got locally.

Really, it works great!

I'm uploading a couple pics, one of the finished install, the other of the existing mic. I guess some of these cars don't have the pre-wired mic, I was lucky.

 

Installed CZ509

I read through this thread and printed it out to have in the car as I started to install my new head unit, a Clarion CZ509 Clarion CZ509 CD receiver at Crutchfield.com from Crutchfield in my 95 S500 W140.

I was really worried because the pre-amp output is only 2V and I was worried because I didn't have the ground loop isolators.

But hats off to Crutchfield. They provide a antennae adapter as well as a wiring harness with very good instructions.

It installed easily and sounds GREAT. No popping, all speakers are working as well. Clean, strong bass too. Paired my phone and my wife said the sound was just as good as my headset. Very happy with all the options on this for the price and the installation pieces provided by Crutchfield.

 

Does anyone have experience between 2 volt preamps and a 4 volt preamp headunit connected to the newer bose amp in a 94? Would 4 volts be too much and cause a problem such as burning out the input stage of the amp? I know from personal experience in other cars with aftermarket amps that 4 volts provided a stronger signal and was louder but also know you have to mach it to the amp input stage specs. What is the bose input?

 

94+ bose amp uses 4-5v differential signal inputs, rca's are not recommended, otherwise you would need extra ground loop isolators, all you should need is a scosche bose integration adapter.

The head unit is a kenwood excelon kdc-x797. The salesman told me it was a 4 volt preamp. Could it possibly be because I grounded the output convertor to the chassis ground on the harness?

you should be using a vw harness with a bose integration adapter, like this.
with the vw harness you need to either switch the pins in the adapter, red and yellow wires to match the mercedes wiring or just wire red to yellow and yellow to red.

 

So I just wired up a new HU as described but the volume is very weak. I picked up an eighty watt output converter still very faint a best. Any ideas please...been working on this for two days with no luck! This is in a 96 E 320.

 

If you used the RCAs, then the HU you are using has low voltage and is not a 4 or 5 volt preamp. The OEM setup uses the amplifified signal (dirty) from the weak headunit (5-7 watts rms) to feed the bose. Using the RCAs puts gives the Bose a clean signal but must be high voltage. If ~2 volts, you would need to turn the volume all the way up for decent output. 4 volts will give the volume you want.

 

The head unit is a kenwood excelon kdc-x797. The salesman told me it was a 4 volt preamp. Could it possibly be because I grounded the output convertor to the chassis ground on the harness?

 

I also used an output convertor I picked up at best buy. I couldn't find the oem 2 locally. It doesn't have the red or yellow wires. Only has the speaker wires and ground. Should I return this one and get the other?

 

Did you connect To the RCAs on the back of radio or used the speaker outputs? If using the speaker outputs, the adapter should have a gain setting to match components.
MBCluster.com Mercedes W140 Instrument Cluster Repair Homepage

 

Thanks for the post! Helped me start the installation of my Clarion HU which appears very similar.
I’m having an issue with the CD or AUX mode though, for some reason when I switch to those modes, I get no sound at all from speakers. Radio mode is working. I also have the popping you mentioned needing the Schoshe products for while in the Radio mode but that popping doesn’t happen with CD or AUX, it’s making me wonder if those modes are not telling the stock amp to turn on and power the speakers.
Did you or anyone have similar issues with Radio working but not other modes? Any solutions? Thanks in advance!

 

Some HUs have separate wires for antenna activation and external amp activation. Mercedes uses one wire for both. Use the HU wire for the external amp activation and it should work.

Jon

 

This is just along the lines of what I was wondering could be the case, thanks Jon!