Re: vintage radios again

[Simon Favre <simon@domain.elided>]

Radios in the 50's had vacuum tubes powered by multivibrators. The 
multivibrators made a buzzing sound that was pretty annoying. They were
also located outside the chassis, or accessible through a hole so you
could easily pull and replace them. They needed to be replaced more often
than turn signal relays, and more often than the tubes themselves. I
would hesitate to put one in an Alfa, even one from the early 50's.

At some point around the late 50's or early 60's, transistor car radios
appeared. The first ones were built with Germanium transistors. They 
were better than the tubes, but not much. They were more reliable, and 
needed no multivibrator to generate 150 volts for the plate circuits.
One of these would be more acceptible in a 50's Alfa, IMO.

I have a Blaupunkt Frankfurt that's supposed to be '63-64 vintage. It's
supposed to go in my Giulietta, but hasn't made the trip yet. ;=) This
one is Germanium, and has a separate amplifier/power supply unit that
hangs off the back. It also has a jumper block to allow use in 6 or 12
volt systems, either + or - ground. It also has AM/FM/SW, but I've never
picked up anything on the SW. It's actually supposed to be on a Marine
band. It has 2 knobs and 5 buttons for station presets (A-A-F-F-M).

BTW, if you're trying to repair one of these early radios, the first
components to be considered suspect are the capacitors, not the 
transistors. Electrolytic capacitors dry out. The ceramic ones can go
bad too. That's what took me several years of fiddling to find out on
the Blaupunkt.

Here's a real auto trivia question: Were any car radios made that had
vacuum tubes and FM? For how many years? I know there were home stereos
with FM and tubes, but car radios? FM stereo appeared about the same time 
as the start of the transition from tubes to transistors, if memory still
serves. I remember building kits with tubes and kits with transistors in
the early to mid 60's.

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