450SLC Becker Mexico Cassette install part 1 – Preparing the radio

Over the last 12 months or so, I have been focused on getting period correct Becker radios installed in my Classic Mercedes cars.    I had never experienced these radios until I purchased my one owner 560SEL back in 2020.   It was owning this car that made me realize how well they work in the car.   I’ve started to view them as part of the overall experience of owning these cars rather than just a way of getting sound.

Last year I started to source the right radios for the cars I owned.   I originally planned to start with my 450SLC, but its taken me a bit longer to sort out the radio for the car.    Based on that, I started on my 560SEC and then moved to my 300TE.    I’ve been pretty happy with these installs, so now it was time to look at the 450SLC again.

The car was originally sold with a Becker Mexico Cassette.  I still have the original manual pack in the car.   The original radio was an ‘M’ series radio.     The separate amplifier was still there, but the Becker was long gone.    I’ve been trying to work out the Becker serial numbers, and while there is some conflicting information out there, I understand that means the radio was built late 1975 to early 1976.   This seems plausible for my car given it was complianced 5/77 and delivered 7/77.   The radios were installed in Australia, not Germany, so they would have been purchased in batches and installed in cars when needed.

Mexico Cassette

It took me a while, but in the end I found a couple of appropriate radios.   Even better they were both ‘M’ series radios, so they should be almost identical to the one originally fitted to the car.   I built a test rig and was pleasantly surprised.   Both radios worked.   I was able to tune FM stations successfully.   I don’t own any cassettes so I could not test this.   However, the ‘wunderbar’ autotune feature did not.   This is a mechanical automatic tuning function and a differentiator from a high end Becker radio like the Mexico and a more mid level radio like the Europa.

Luckily a friend in the MBCNSW came to the rescue and was able to help me get the radios repaired.   My focus was to make sure AM/FM and the ‘wunderbar’ were all working properly.   I don’t own cassettes anymore so I wasn’t really concerned with the Cassette function.

When the radios came back, I was really happy with their operation.   The ‘wunderbar’ is such a great feature.

Next step was to test how I was going to get music and calls from my phone into the radio.   My default choice was the iSimple Tranzit BLU HF FM injector.   I’ve used this successfully on my 560SEC and 300TE.   As well as the FM injector option, it also has the possibility of an AUX in connection.

Mexico Cassette

The Becker radios without cassette, such as the period Europa II or Grand Prix have an AUX in port.   This is supposed to be used by the external tape deck.   Obviously a Mexico Cassette doesn’t need an external tape deck.   There is another port on the back of the Mexico which I understand is used for the German traffic adaptor.   This is mono only, as the Traffic input would not require stereo.   I purchased a mono input adaptor (normally used for the earlier mono Europa and Grand Prix), and while I could get audio through it, I wasn’t very happy with the sound.  I think I’ll use the FM injector as before.

aux port

Finally there was the the question of output.   The Becker radio outputs 2x7W at 4Ohms.   My working assumption was that with four modern speakers, it would be better to use a modern amplifier.   This is trivial with the Mexico Cassette, as it already uses a separate amplifier.  There are ready made adaptors on the market that accept the Becker amplifier plug and turn it into RCA outputs.   I tried one and it worked really well with a powered computer speaker on the Bench.    I have another one of the small Alpine amplifiers I used for the 560SEC install I can use here if needed.

Mexico Cassette

Before installing any of this in the car, I have been doing extensive testing on the bench.  Much easier than once the radio is in the car.  During most of this testing I held the assumption I would use the external amplifier.  After hearing a Europa II Stereo without the amplifier in a friend’s W108, I’m not so sure.

In any case, the Becker Mexico Cassette is ready to install.   Now to speakers.

4 comments to 450SLC Becker Mexico Cassette install part 1 – Preparing the radio

Leave a Reply

You can use these HTML tags

<a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <s> <strike> <strong>