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Who's running a Becker?

Started by 1980sdga, 06 June 2011, 06:04 PM

1980sdga

How did you figure the pinout? I figure it would be hard to screw anything up tinkering with it.

1980sdga

Before and after:





I know, I need to clean her up  :P  I still have the passenger side torn apart from working on the AC. I figured it would be a good time to change radios.

The stereo sounds OK in the car. The old Jensen radio I was using was overdriving the speakers a bit and the Becker seems to be a better fit with the stock speakers. I pulled the fronts and cleaned them up a bit. No cracks or anything so I'm just going with them for now.

I still need to work out speaker polarity (Any easy way to tell + from -) and hit the fader switch with some contact cleaner because it's scratchy.  It did wonders for the radio!  (I've used the Radio Shack cleaner/lubricant spray for years and it can work miracles on older switches, pots, etc.)

The ipod input is AWESOME and I love the look of the old Becker!

I'm considering trying to refinish the wood around the AC controls to get rid of those cracks...

jbrasile

Great Jon!

Amazing how these old Beckers just look the part....

If the cracks on the cc panel are not too deep you may get away with just sanding enough to remove the cracks and applying clear coat.

I am not an expert on wood repair and have never done this myself but one of the guys who does this type of work for me avoids removing all the lacquer whenever possible.

Have fun!

Joe

carl888

#33
I have nothing to contribute except to say that I love them!!

(But if you have any questions about installation or rebuilding them, feel free to ask)

















1980sdga

What's the car in the last pic? Is that a prancing horse on the steering wheel?

I dug into mine far enough to add the aux. in and clean/lube it.  I didn't do anything with the tape deck because I was afraid of messing the whole unit up.

Great pictures!  Part of the allure (To me at least) of the Beckers is the fact that they came in some of the legendary supercars from across the pond  8)


Casey

They do look nice and have chrome which is definitely a nice touch.  I have to say I really don't like the newer ones, but the Mexico and Mexico Cassette look really classy.

carl888

Quote from: 1980sdga on 09 June 2011, 08:51 AM
What's the car in the last pic? Is that a prancing horse on the steering wheel?

I dug into mine far enough to add the aux. in and clean/lube it.  I didn't do anything with the tape deck because I was afraid of messing the whole unit up.

Great pictures!  Part of the allure (To me at least) of the Beckers is the fact that they came in some of the legendary supercars from across the pond  8)



Yes, early 308 GTB from June 1976.  And I agree with the look of the Beckers in period cars, to see one in a Ghibli or Daytona is just lovely.  They do seem to work best with a bit of timber around them I think.

Sounds wise, remember these units are 40 years old.  The amplifier is 7 watts per channel, and it is NOT designed to drive low impedance loads under 4 Ohms.

If you wish to take it seriously, start by replacing all the electrolytic capacitors in the amplifier section.  The amplifier is not bad, it's a basic class B unit, unlike the class G or H rubbish you can buy these days!  If you wish to keep going, you can do the electrolytics in the unit itself.  The MKP series plastic capacitors should be fine.  Aligning the tuner section is a bit of an art, you'll need some very specialised test equipment, and an understanding technician.

With 7 watts, you'll need to find some efficient 8 ohm speakers if you are using 4 speakers.  I notice some of the modern speakers like JBL are claiming a 2 ohm impedance these days, crazy.

The tape section is pretty easy to work on, new belt, lube the motor and align the head (Assuming you, umm, play tapes :)

I have a service manual for a Mexico, I can post it if you like, I'll be home in a week and could do it then.




1980sdga

I would like to see the manual!  I don't plan on doing any work to the tuner but it was interesting to look at the inside of it. I assume that the section with the "slugs" that slide inside tubes is the tuner section?  Weird that it had 5 of them...

I may be interested in replacing the caps as well as a speaker upgrade in the future!

koan

Quote from: 1980sdga on 10 June 2011, 06:31 AM
I would like to see the manual!  I don't plan on doing any work to the tuner but it was interesting to look at the inside of it. I assume that the section with the "slugs" that slide inside tubes is the tuner section?  Weird that it had 5 of them...

That's part of the tuner and it's called permeability tuning. It's where the inductance of the tuned circuit is varied rather than the capacitance which is the usual way. Permeability tuning has some advantages, can't recall what they are though, it was considered up market.

I'd like to see the manual too Carl.

koan
Boogity, Boogity, Boogity, Amen!

carl888

No problem, I will be home in a week and I can scan the manuals then.

I think the advantages of permeability tuning is its superior frequency stability.  Not that I'd know, my cursory understanding of circuits stops with triode coupled amplifiers from the 1940s lol.

Something else just occurred to me, the Australian FM de-emphasis time constant is 75 microseconds. I think Europe is 50ms. I wonder how that manifests itself in terms of sound quality if you use a 50ms unit in a 75ms location?  Anyone know?   

koan

Quote from: carl888 on 11 June 2011, 05:06 AM
I think the advantages of permeability tuning is its superior frequency stability.  Not that I'd know, my cursory understanding of circuits stops with triode coupled amplifiers from the 1940s lol.

Are you talking about Lee De Forest's new three-electrode vacuum tube? ;)

Quote
Something else just occurred to me, the Australian FM de-emphasis time constant is 75 microseconds. I think Europe is 50ms. I wonder how that manifests itself in terms of sound quality if you use a 50ms unit in a 75ms location?  Anyone know?   

We adopted the US pre- and de-emphasis time constants in AUS standards and not the UK/Europe values. I think the result would be slightly emphasised highs.

koan





Boogity, Boogity, Boogity, Amen!

TJ 450

Quote from: koan on 11 June 2011, 07:02 AM
We adopted the US pre- and de-emphasis time constants in AUS standards and not the UK/Europe values. I think the result would be slightly emphasised highs.

koan

That would be correct... less attenuation.

The joys of noise. 8)

Tim
1976 450SEL 6.9 1432
1969 300SEL 6.3 1394
2003 ML500

koan

I doubt it makes much difference in practice, electronic components of that vintage had a tolerance of +/- 20%, with that spread of values the 50uS and 75us curves would overlap anyway.

Some electrolytics back then were +20 -50%.

koan
Boogity, Boogity, Boogity, Amen!

carl888

#43
Quote from: koan on 11 June 2011, 07:02 AM


Are you talking about Lee De Forest's new three-electrode vacuum tube? ;)






Yes, that's the one!  I think he sold that patent for the triode for a pittance





1980sdga

You guys will definitely get more out of those manuals than I will.