New head unit install in W140 92 300SD

[dieselsteve]

#1- what a great forum!!!!! Scott form LJAudio THANKS FOR THE GREAT INSIGHT AND INFO!!!

i HAVE 1992 300SD(W140) It has no CD and the rear speakers have no sound out. ( probal y amp, was squeling and poping and now dead

I have a Sony CDX-C7050X HU with a 10 dISC CHANGER CDX-747X that I had in my old 87 SDL mercedes.

I want to install this head unit and CD changer in the 92 and add a new subwoofer amp to drive the rear subs ( Will upgrade speakers at some point). Use stock system for all doors and center channel.

I now I need to extend the Antenna and the control wire for the antenna to the front. AND I will need a 4 channel line level converter to go from the Sony to the BOSE amp.

Questions:
1. the HU has 50Wx4 and front and rear pre-amp out with separate sub pre out. Which way should I go with the line convertor- from speaker down to line or line to correct level. the HU can goto 4Volts output.

2. What else do I need?

3. Where should I pull 12V for the HU from? same place as the BEcker?

4. Does any one ahve the pin out for the channels ( Left rear, etc.) that go into the amp form the A2 module of teh Becker? The diagram form teh ETM doesnto break this out.

Thanks in advance.
Steve
1992 300SD soon to be rockin'

[SCLJA]

I use a soundgate device to run from your sony's speaker level to a balanced high level input to the stock amp.The 4 volt signal is not enough to drive it (this is two channel input to the stock amp). There is a three conductor plug coming off of the 1532 tuner module in the trunk that is the input to the stock amplifier. This is where you will tie in to the stock amp. the center pin is a common ground anthe two outside pins are the + inputs to the amp. As far as getting power you should run a new constant power wire for the the sony radio as the stock one is designed for @5 amps and the new radio will require at least double that. The rest of your wires can be found behind the radio. Check amp turn on as you might need to run one along wiith the antenna wire. Good luck! And I do appreciate your compliments.

Scott@lajollaaudio

[dieselsteve]

Scott,

Then I only need a 2 channel line level converter? vs. a 4 channel?

The stock amp only has 2 (L&R) coming into it?.

Thanks
Steve

[SCLJA]

You are correct 2 ch.

Scott

[dieselsteve]

Scott,

Where should I put the converter?
My thought is to put it as close to the low level inputs as possible. The signal will be at the lowest level for the least amount of time/distance to reduce possible noise interference. Logical?

Are they adjustable?

What level do I set it for?
I have access to an O'scope and a DMM ( Fluke 87 and Fluke scope, and a 20Mhz o'scope)


Thanks again!!!!
Steve

[SCLJA]

I would put the adapter in the trunk as you said, as far as setting up the adapter I would hook it up and then adjust it so your volume control at max just starts to clip. Then test it and make sure it works good if not adjust it some more. Make sure you get an adjustable one!

Scott

[dieselsteve]

Hi All,

Jsut a big trhanks to all involved, Scott at La Jolla , Mike Y for electrical diagrams.

Installed my Sony HU and CD changer, use the Bose amp,

Sytem rocks!! Sounds MUCH BETTER then the 1432 I had in there before, especially the CDs!!!!!!

Dave Mathewsa and PInk Flord are awesome!!!


I only have 2 of the 4 subs firing. The BOSE has a sub channel out.

$800 CDN to fix just the amp $200 for a new amp to drive just the subs and HU has a sub out and is adjustable !!

Thanks again!!
Steve

also , I coudln't get enough drive at full volume to clip the amps.
I set the impedence amtcher to about 2/3 of the way. I had it at 3/4+ and the volume was WAY to load with the deck at low level.

Does this sound OK? our should I get it to clip?