Now that brings back memories ! When I was still at school I was always keen to acquire peoples electro-mechanical junk to play around with and to dismantle to see how it worked.
A vibrator type car radio was amongst those, and I remember cutting off the vibrator can and fiddling for hours trying to get it to operate reliably. When it ran OK the radio, which used octal base valves, did work. It was in a large metal box intended to be fitted in the engine compartment and the two controls connected by mechanical flexible cables to a small control head. Goodness knows what car it was from!
A later generation of car radios I recall used "special" valves which would operate with 12 volt ht supply. I think these were the RF valves, and those sets had solid state audio stages. I discovered that near equivalent contemporary TV valves (intended for use at conventional ht) would still operate in these sets.
