Confused with tube radio

debe said:

Here in Australia there was car radios in the early 60s that had 12V valves in the front end & Germanium transistors in the audio stage. They seemed to work well.

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Would they have been OC16 (or similar?), sort of like a short fat bolt, with base and emitter wires coming out the thin end of the bolt, and obviously bolted to a heatsink. They were usually single ended, and used an output transformer, quite common in old 'almost' pre-transistor car radios. I used to have a couple in the spares draw at work - along with a wide collection of vibrators.

Nigel Goodwin said:

I used to have a couple in the spares draw at work - along with a wide collection of vibrators.

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Out of the context of valve radios in cars, that could be interpreted - well - "differently".

Diver300 said:

Out of the context of valve radios in cars, that could be interpreted - well - "differently".

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More fun at work!

Very similar Nigel, Threaded stud in the middle, B & E were pins.

debe said:

Very similar Nigel, Threaded stud in the middle, B & E were pins.

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I'm just going from memory, from transistors I haven't seen for many decades, but I seem to recall the OC16 had a couple of insulated wires sticking out?, so sounds similar but not identical.

A quick google finds a picture

Dick Cappels said:

Hey, with only 12 volts of plate voltage, how much grid bias can you have and still get any plate current?

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i built a tube preamp using subminiature tubes. it didn't work well with 12V B+. upping the plate voltage to 24 worked ok though. the tubes were rated at 100V plate voltage, so the gain, while adequate for the application (tube fuzz distortion pedal/ tube preamp), it wasn't nearly what it could have been with 100V on the plates. i thought about putting in an inverter/voltage multiplier to get 100V, but with 24V, there was enough gain for it to work.