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Confused with tube radio

I acquired a fada neutrodyne 175 a battery powered tube set at a flea market and noticed that it has three tuning dials. Got a few questions. How do you tune this set? Whats the easiest way to power this thing? (I know it needs all three voltages a,b,c.) Never worked on battery powered tube radios before so any advice would be appreciated.
Thanks in advance -Ray
 

Nigel Goodwin

Super Moderator
Most Helpful Member
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.

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

Super Moderator
Most Helpful Member
Very similar Nigel, Threaded stud in the middle, B & E were pins.
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 :D

OC16a.jpg
 

unclejed613

Well-Known Member
Most Helpful Member
Hey, with only 12 volts of plate voltage, how much grid bias can you have and still get any plate current? :D
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.
 

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