The Forum

Garage => Interiors & Exteriors => Topic started by: s class on 16 September 2009, 03:28 AM

Title: Becker mexico - amplifier upgrade
Post by: s class on 16 September 2009, 03:28 AM
Hi,

I have a becker mexico pinstripe that I bought off Cam, and I'd like to get it going.  It is lacking the external amplifier, which is no big deal really as I'd like to use something modern.  So I need to know the pinout of the DIN cable that comes out of the radio - can anyone help?  Well, if goes further than that really, the cable has been cut already, so I actually need to know which colour wire is which in the multicore cable. 

I could of course just fire it up and play around.  I'm guessing there will be one or more grounds, and a left channel + and -, plus a right channel + and - .
Title: Re: Becker mexico - amplifier upgrade
Post by: TJ 450 on 16 September 2009, 05:11 AM
That was unfortunate timing... I just had mine out for an input modification. I am dissatisfied with the sound, as the shielding on the cable is insufficient... I can hear all sorts of interference. Needless to say, I will be removing it again and experimenting with different cabling.

Has the cable on yours been cut at the unit? What's what should be apparent when you separate the conductors. I think the signal cabling consists of a pair of shielded conductors within another layer of shielding.

My previous complaint with these units was a harsh, gritty treble and glassy midrange... I'm confident that all these issues lie in the cabling, as despite the background noise, the sound out of my unit now is remarkably free of distortion and goes quite loud with the W123 speakers. Thus, it would be worthwhile removing the original cable altogether and sourcing something better, or better still, mount some RCA jacks on the back of the Becker so you can use some modern cabling to your new amplifier and simply plug it in.

Tim
Title: Re: Becker mexico - amplifier upgrade
Post by: s class on 16 September 2009, 05:41 AM
Quote from: TJ 450 on 16 September 2009, 05:11 AM
...... or better still, mount some RCA jacks on the back of the Becker so you can use some modern cabling to your new amplifier and simply plug it in.

That is rather clever, embarrased I didn't think of it. 
Title: Re: Becker mexico - amplifier upgrade
Post by: s class on 16 September 2009, 05:43 AM
Well, step 1 will be to get it working.  Step 2 will be the amp connection (probably RCA as you suggest).  Step 3 will be the koan-style input modification, though I will be mounting the connection at the back.  My intended use for the extra input will be an external CD changer.  I don't know too much about whats on the market - can one buy units that have a stereo line out? - and presumably some form of remote control?
Title: Re: Becker mexico - amplifier upgrade
Post by: s class on 16 September 2009, 05:44 AM
Quote from: TJ 450 on 16 September 2009, 05:11 AM
My previous complaint with these units was a harsh, gritty treble and glassy midrange... I'm confident that all these issues lie in the cabling,

Is this with the original becker amp, or some other unit?
Title: Re: Becker mexico - amplifier upgrade
Post by: TJ 450 on 16 September 2009, 05:50 AM
That's with the original amp, as there is no form of noise filtering. I fitted an RF choke like I seem to recall seeing on Koan's amp.

I mounted a full size stereo TRS jack on a dongle out the back as per Koan's instructions too.

Tim
Title: Re: Becker mexico - amplifier upgrade
Post by: Papalangi on 16 September 2009, 10:27 AM
A quick search came up with this which unfortunately is not quite what you wanted,
http://www.crutchfield.com/p_130FM1289/Pioneer-Premier-CDX-FM1289.html?tp=133

I've searched using "universal cd changer" and "add on cd changer" and so far only come up with FM modulated units.

This one is cheap at $109 from http://www.onlinecarstereo.com/CarAudio/ProductDetail.aspx?ProductID=18393
Michael
Title: Re: Becker mexico - amplifier upgrade
Post by: s class on 22 September 2009, 07:07 AM
OK, I have been playing with the Mexico.  I had about 50mm remaining of the umbilical cord, and I stripped it back, and then stripped the constituent wires.  I found about 4 coaxes, and several other thin wires.

I powered the unit up and probed the outputs with an oscilloscope, and subsequently discovered that at least half the wires in the bundle don't go anywhere, and pulled out easly.  I was left with the screen (ground), a thick +12v supply and two coaxes - left and right audio presumably.  So in the end it was quite simple. 

What I see on the audio lines with the oscilloscope is not what I expect, but admittedly I didn't have an aerial connected.  So the next step is to give it an antenna, and perhaps put the audio into an amp and speakers so I can hear what's going on. 

I fitted a new belt to the cassette mechanism, but it is still not engaging.  More investigations needed. 
Title: Re: Becker mexico - amplifier upgrade
Post by: Papalangi on 22 September 2009, 11:17 AM
I don't know how much if any info this guy will share but he does sell a cable that plugs into the DIN socket on the back of the radio to add an input.  They used to be for the Mexico's with cassette but now he lists them as only for radios without cassette.

http://www.koenigs-klassik-radios.de/_py_accessories/c-28-0-0-0-0-0/

Michael

Title: Re: Becker mexico - amplifier upgrade
Post by: TJ 450 on 22 September 2009, 12:35 PM
I was led to believe that those DIN inputs were mono, but there may be exceptions.

I don't know what you had the scope on s class, but it may have been out of band noise or similar in the audio signal. The extra conductors may have been for shielding purposes.

Tim
Title: Re: Becker mexico - amplifier upgrade
Post by: s class on 22 September 2009, 01:25 PM
I think the DIN input is indeed mono - intended for use with the VK5 kurier. 

TJ, I expected to see the audio signal (which is presumably mostly noise at this stage) increase and decrease with the volume control, but that was not the case. 
Title: Re: Becker mexico - amplifier upgrade
Post by: koan on 22 September 2009, 05:04 PM
Quote from: s class on 22 September 2009, 07:07 AM

I found about 4 coaxes, and several other thin wires.


Doesn't sound right, shouldn't be that many connections, some one may have got at it.

That DIN socket on the back for the "Radio Traffic Adaptor" needs a shorting plug with pins 1 and 2 jumpered for the radio to work normally.

I've read somewhere the sockets are mono early and stereo post Mexico.

I have a circuit scanned in if it's any use.

koan
Title: Re: Becker mexico - amplifier upgrade
Post by: Papalangi on 22 September 2009, 06:43 PM
I think there are two socket on the back of the Mexico but could be quite wrong.  The Europa II sitting in front of me has an input for a traffic adapter and an stereo input for a record player or tape recorder.

This place claims to have service manuals in PDF but I've no idea if they are telling the truth. http://www.becker.manuals-in-pdf.com/becker-c-242.html?page=1&sort=20a

If you can get FM modulators there you could record a test tone and play it back through a modulator to identify left VS right.

Michael
Title: Re: Becker mexico - amplifier upgrade
Post by: s class on 23 September 2009, 04:28 AM
My mexico has the DIN socket on the back, with the shorting plug still present.  I also have an additional "mini" DIN socket, the purpose of which I dont know. 
Title: Re: Becker mexico - amplifier upgrade
Post by: Big_Richard on 23 September 2009, 04:56 AM
indeed, there is a mini din connector of 8 pins, i just looked at my old one. What does this connect to ?
Title: Re: Becker mexico - amplifier upgrade
Post by: Papalangi on 23 September 2009, 08:45 AM
Here is the diagram for the Mexico,
(http://www.beckerautosound.com/Classic/Mexico%20installation%20instruction.jpg)

Here is the diagram for the Europa II,
(http://www.beckerautosound.com/Classic/europa%20II%20stereo.jpg)

Here is the diagram for the Gran Prix,
(http://www.beckerautosound.com/Classic/UMRICHTER%20STEREO%2069%20TO%2071%20WITH%20SCREW%20ANTENNA%20TRIGGER%20CONN%201.jpg)

(http://www.beckerautosound.com/Classic/Europa%20Stereo%20MU%20back%20panel.jpg)

At least I hope the links  work.

Michael
Title: Re: Becker mexico - amplifier upgrade
Post by: jpstuckey on 23 September 2009, 03:34 PM
The body donor car that we bought already had a fancy Alpine setup installed and all original wiring deleted, so I did the same oscilloscope dance as S-class and wired in a pair of RCA jacks.  Sound quality is good, but volume level is modest in spite of amp output.  I set the gain all the way up on amp, but it is obviously still a bit lower than original Becker tin box.  What I would really like to have is a bit of bass; anybody found something that works without being aesthetically objectionable?

John
Title: Re: Becker mexico - amplifier upgrade
Post by: koan on 23 September 2009, 11:08 PM
Quote from: Patrick Bateman on 23 September 2009, 04:56 AM
indeed, there is a mini din connector of 8 pins, i just looked at my old one. What does this connect to ?

Marked on the circuit as "Measuring socket/Remote Control Socket",  just earth (pin1) and 4 wires (pins 3, 4, 7, 8)  connected. Can't immediately see what it's for, seems to be connected AM and FM detectors. Might allow a remote control box to tune and  band select.

Don't recall seeing it on the back of mine but that doesn't mean it's not there, no longer have photographic memory (?)  <- smiley for failing memory.

koan
Title: Re: Becker mexico - amplifier upgrade
Post by: s class on 24 September 2009, 12:05 AM
koan, that would make sense.  WHen installed in centre-divider 600's and 6.3's, these beckers were equipped with a second unit in the rear compartment that provided a volume control and seek/tune functions. 
Title: Re: Becker mexico - amplifier upgrade
Post by: Big_Richard on 24 September 2009, 05:42 PM
wow, an optional input for a record player - I've always wondered if there were ever a design to play actual vinyl records in a car with some level of stability. Nowadays there are record readers that use non contact laser pickups versus the traditional stylus for many thousands of dollars, but they didnt exist back then!

Title: Re: Becker mexico - amplifier upgrade
Post by: OzBenzHead on 25 September 2009, 03:34 AM
Quote from: Patrick Bateman on 24 September 2009, 05:42 PM
wow, an optional input for a record player - I've always wondered if there were ever a design to play actual vinyl records in a car with some level of stability. Nowadays there are record readers that use non contact laser pickups versus the traditional stylus for many thousands of dollars, but they didnt exist back then!

PB: I do remember a record player in a mate's car back in the late '60s.  Can't recall the brand or name, but it played 7" vinyl -- albeit rather skittishly on most Oz roads.  It was aurally painful and wasn't a market success, at least in Oz.

Here is a heap of them:  Link (http://www.google.com/search?q=car+record+player&ie=utf-8&oe=utf-8&aq=t&rls=org.mozilla:en-US:official&client=firefox-a).
Title: Re: Becker mexico - amplifier upgrade
Post by: Big_Richard on 25 September 2009, 04:05 AM
awesome, that's very interesting OBH  8)

being born in the 80's means i missed out on a lot of cool things like that ;)

I never really owned records my self, my older brother and sister did - All i had were "compact cassettes" and then "compact discs" Oooohh ahhh!  ::)

the invention of highly efficient compression algorithms such as the MP3 format, has rendered physical  "recordings" of any type practically redundant. Everything can be done electronically without ever exchanging anything physical at all. Today's kids have it all at the click of a mouse ;)



Title: Re: Becker mexico - amplifier upgrade
Post by: OzBenzHead on 25 September 2009, 07:36 AM
Quote from: Patrick Bateman on 25 September 2009, 04:05 AM
[...] highly efficient compression algorithms such as the MP3 format [...]

Have you tried AAC format, PB: "lossless" compression? Doesn't clip the extremes like MP3 does (files are marginally fatter than MP3, but not by much).

Examples:
Song length -- 3 m 20 s
1. AIFF -- 33.7 MB (one of the two uncompressed "full fidelity" formats)
2. WAV -- 33.6 MB (the other uncompressed "full fidelity" format)
3. AAC -- 3.2 MB (a.k.a. M4A and 'Apple Lossless')  "high fidelity" -- to almost all adults' ears sounds full, not clipped
4. MP3 -- 3.1 MB (very lossy at upper and lower ends -- very noticeable through good reproductive equipment)
and I shan't even start on OggVorbis or other formats.  ;)

Title: Re: Becker mexico - amplifier upgrade
Post by: Big_Richard on 25 September 2009, 09:00 AM
I think i need to try this AAC format, sounds very promising. Although, I'd hardly consider the audio equipment in this house high end - the only amplifier here was produced in the mid 70's  ::)

out of interest, i have tested my audible hearing range with a tone generator, i can easily hear up to 21kHz. The lowest i don't know - since that would be limited by the responce of my povo speakers/amp.  8)
Title: Re: Becker mexico - amplifier upgrade
Post by: Papalangi on 25 September 2009, 03:17 PM
I used to make "mix tapes" all the time to play in my 1972 Renault 12 Estate.  I had one Led Zeppelin tape that had a skip in it.  One day while playing real loud at school, it started skipping.  I counted four (the number of times it had skipped during recording) and whacked the side of the car.  The music stopped skipping!

I got some of the oddest looks form my friends.

Michael
Title: Re: Becker mexico - amplifier upgrade
Post by: s class on 24 May 2010, 03:05 PM
Finally, I have the Mexico working after attention by a Becker specialist here.  He got the tape transport sorted, repaired the power supply to one board that wasn't getting any juice, and got the seek function to work (mostly - more on this later).

I have identified the L and R output co-axes, and am busy mounting RCA jacks on the rear. 
Title: Re: Becker mexico - amplifier upgrade
Post by: s class on 07 June 2010, 06:56 AM
The RCA jacks are mounted.  I must organise a picture.

I have found out that the VK5 traffic adaptor has a little mono/stereo toggle switch on it.  Which is interesting. 
Title: Re: Becker mexico - amplifier upgrade
Post by: TJ 450 on 07 June 2010, 10:19 AM
Sounds good S Class (pun not intended 8)).

I recently fitted a modern head unit in place of the Becker in the 6.9, while I was driving the car daily. I also fitted a separate power amplifier a few months ago, along with a 10" Cerwin-Vega subwoofer in a sealed enclosure painted in Mission Brown. The sub is located directly behind the driver's seat and actually integrates quite nicely with the front 4" dash speakers.

What I intend on doing now is performing this modification to the Mexico, so as to make use of the 50WPC power amplifier and mount the modern deck back in the 450. There is no stereo in the 450 at the moment.

Previously, I just had a TRS socket hanging out the back of the Mexico as a trial.

Tim
Title: Re: Becker mexico - amplifier upgrade
Post by: s class on 08 June 2010, 03:46 PM
I supported the radio in a milling machine to make the holes precisely.

(http://i54.photobucket.com/albums/g85/mercedes_s_class/becker/DSCN2751.jpg)
Title: Re: Becker mexico - amplifier upgrade
Post by: TJ 450 on 08 June 2010, 07:36 PM
A job well done. They look like good quality sockets too.

Tim
Title: Re: Becker mexico - amplifier upgrade
Post by: s class on 09 June 2010, 12:20 AM
TJ, I didn't specifically look for gold plated etc etc plugs, I selected them because I wanted ones that were insulated from the chassis.  The mounting location I selected was absolutely the only one with sufficient space inside.  I've seen a few mexicos, and there are some variations, and so potential mounting locations vary.