In article ,
Bob Eager writes:
On Sat, 05 May 2018 09:01:04 +0000, Andrew Gabriel wrote:
Reminds me, parents used to have a valve car radio.
It started in an Armstrong Siddeley car (don't know if it was original
fit, or if my dad fitted it).
When I worked at Technical Trading (q.v.) the shop manager (Chris, I
think) had an Armstrong Siddeley.
Dad transferred it to a 1965 Vauxhaul
Victor. The dashboard part had the tuner and preamp valve stages, which
was connected with a thick umbillical cable to a box in the passenger
footwell which had the power output stage and transformer, and the HT
generation and rectifier valve.
That is just how I remember Chris's radio, so perhaps it was standard
fit.
I just did some googling, and this is the floor unit:
https://www.radiomuseum.org/r/radiom...mplifie_4.html
It looks like it has some type of standard interface which can be used
with many tuners. I searched but although there are pictures of hundreds
of 1950's radio tuners, I can't find the one we had, which I remember
very well.
(I also remember the strange hinge arrangement on the doors, and the
preselect gearbox)
So did dad's. This might have been standard on Armstrong Siddeley.
Wikipedia says they used Wilson pre-select gearboxes. Apparently,
Wilson started off designing tank gearboxes in WWI, and developed
the first gearbox allowing tanks to be driven by one driver,
instead of needing two drivers shouting instructions between them.
The HT generation was driven by a plug-in vibrator which was basically a
changeover relay operating as a buzzer in a metal can with sound and
vibration absorbing material around it, driving a centre-tapped primary
of a step-up transformer. The vibrator was worn out and the box usually
needed a kick to get it started.
I remember those things. Also used in various military sets. I had a box
of them, 'won' from the Royal Marines in Portsmouth.
https://en.wikipedia.org/wiki/Vibrator_%28electronic%29
The top picture is similar, but the vibrator had no mechanical
connection to the case, and pushed into some foam or felt (I forget)
which insulated the vibration from the can. Also, it was 12V.
The circuit diagram is what I remember too, except it had a valve
diode and not a voltage doubler rectifier as shown in the picture.
--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]