In article ,
Scott Dorsey wrote:
Kenneth Scharf wrote:
On 08/13/2011 01:48 PM, Richard Knoppow wrote:

Among other applications sub-miniatures were used in
hearing aids and model aircraft controllers.


Subminiature tubes were developed as bomb fuses for use in mines and
torpedoes.

I think indeed the first subminis that came out of the Raytheon plant
were intended for proximity fuses. Those were designed with very heavy
reinforcement so they could handle heavy acceleration parallel to the
plate, and that same technology made them useful in a lot of other
low-microphonic applications.

Some of the last ones that came out of the plant were spares for the
first and second generation B-52 navigation systems, which used a
von Neumann machine made up of around 250 submini tubes.

In the meantime they went into everything from Army field radios to
weather balloons to condenser microphones.

They were just a hell of a great technology if you ask me.

I think that the first Raytheon subminiatures were from 1938-39 and
made possible electronic amplifiers for hearing aids that could be
worn in a man's suit. Beltone and Sonotone were producing amplifiers
with these tubes that were about the size of a pack of cigarettes in
1940. The proximity fuse tubes were a ruggedized development of an
already-mature product made in quantity for a ready civilian market.

I don't know when Raytheon last made subminiature tubes, but do know
that they were going into new-manufacture missile warhead guidance
electronics until the early-mid 1970's.

Sonotone did have their own line for subminiature tubes, but I don't
know whether that was set up during WWII or afterward. Their first
"transistorized" hearing aid hit the market in 1953, but it was a
hybrid that still used tubes plus one transistor in a cigarette-pack
amplifier.

Hank