W140 replacing Becker 1432, keep tuner?

[sixto]

I'm going to replace the Becker 1432 head unit in my 93 300SD. I'd like to keep the Bose amp and speakers. Should I wire the new head unit's outputs through the tuner or bypass the tuner and wire the inputs and control signal into the amp?

Thanks,
Sixto
93 300SD

[Hit Man X]

You're in for a LOT of work to rewire it all. Is your current 1432 bad?

Many had CD changer output too if you're after that. You could always upgrade to a later Becker from the 140s too.

[sixto]

I want in-dash MP3 and an aux input.

This seems like less work than other options since I can avail of the DIN cable for music and power signals for the amp. And the existing fader. I don't listen to the radio much so I'll get an antenna that doesn't have a mast. Leave it behind the dash somewhere.

It will be a lot of work to fit a 1492 or newer unit since the cables are all different. The 1432 has two 4-pin connectors, an antenna signal connector and an 8-pin DIN connector. The 1492 and newer units have the VW style connector that looks something like this -

http://www.discountcarstereo.com/images/pie/vw_8pin.jpg

Sixto
93 300SD

[Hit Man X]

I've only taken apart cars with the 1432. The seperate box in the trunk is odd along with the door amps. Wasn't aware all the wiring changed for the later 140s.

Wonder if you could use the existing preouts on the new HU to power the current Bose amplifier? Is the 140 setup how the 400Es are or do they have a ton more speakers?

[sixto]

There's an adapter that drops speaker level outputs to the level the Bose amp needs. Pre-outs don't provide enough of a signal even at 4V or 5V.

The W140 has 4 6.5" woofers in the rear deck, a full range in each rear doors, mid and high separates in each front door and a center channel by the rearview mirror. Dash speakers are for the phone.

Sixto
93 300SD

[Hit Man X]

Sounds like a good vehicle to rewire if you wanted to go all aftermarket.

How large is that Bose amplifier?

[sixto]

Maybe. It has the fuel tank between the trunk and cabin so any subwoofing will probably have more effect outside the car than inside.

Amps-wise, I don't know. Physically it's the size of a 603 IP. I think the system is set-up at 0.5 ohms impedance or something like that so a little power goes a long way. Makes it difficult to go with aftermarket speakers.

Sixto
93 300SD

[Hit Man X]

Odd setup. I've never listened to one cranked up real high, so I can't comment. But I bet it's a hell of a lot better than the Becker stuff in the 126s.

[sixto]

A payphone handset sounds better than the stereo in a W126

Sixto
93 300SD

[Hit Man X]

LOL. The setup in my SD was comical at best... but I suppose in 1985 it was hott-stuff. I was suprised how much better the '86+ stuff sounded. The '88+ was probably decent.

[sixto]

The 10-speaker set-up in my 91 300SE was okay. The problem with the Becker Silverstone CD changer was that it took a minute to go from one disk to the next and it wouldn't play home burned CDs. It didn't play a few store-bought CDs. I fitted a Sony RF changer I had from another car and the sound was just as good to me as the Silverstone.

Sixto
93 300SD

[Hit Man X]

That's why I tossed the 754 from my SDL, the FM reception was total garbage.

Even the strongest stations barely came in with the mast all the way up. Now I have an HU with 6v preouts

I've been meaning to ask ya, how is the rear legroom in the SWB 140 compared to the LWB 126?

[sixto]

I didn't measure but you see more rear footwell in the LWB 126. 140 is wider, though.

Sixto
93 300SD

[Peter Guenther]

Be prepared for a lot of work, The setup in your 93 goes like this, the dash unit in the front that has the Cassette, and control function. The tuner is in the trunk at the base of the wheel well, there is a large din that connects these two. If you have the CD it is first routed thru the CD before it goes to the tuner, the CD gets its power thru a "Y" from the tuner. The antenna goes to the tuner, most likely it has a splitter that allowed the analog phone to use the fendr mounted antenna. The 7 channel amp in the trunk drives 11 speakers, 2 on each side in the front doors (4 ohms I think) in enclosures, one each side in the rear doors (4 ohms I think), a tweeter behind the rear view mirror (who knows), and two speakers on each side on the rear deck (2 ohms each tied in series) for bass. The tuner outputs go to the Bose amp (top of wheel well driver side) which is controlled by the fader on the console, and the right to left is controlled by the dash contol unit, The two outboard speakers were for the Cell Tel audio and served no other purpose and were powered by the Cell Tel and fed by one pair terminated in the trunk area. The radio was muted by the Cell Tel. The antenna was raised by either the radio or the Cell Tel.
I think you have a interesting journey making sense of the speakers and the associated wiring

[sixto]

I think I've made sense of it based on info from Scott and alldatadiy.com. All I have to do (!) is tell the amp to turn on and provide it with music. I know the wires to tap into. Question is, do I feed the tuner unit or the amp directly? And what is the turn on signal (+12V, +5V, ground, something else?)?

If my portable MP3 player has enough of an output for the amp, I don't even need a stereo unit. I'll enjoy heat from the stereo cavity through the winter and cap it in the spring

How do you set left-right balance with the 1432?

Thanks,
Sixto
93 300SD