sub mini tubes on ebya..

[lockedout]

http://search.ebay.com/search/search.dll?query=miniature++tubes&ht=1&sosortproperty=1&from=R10&BasicSearch=

sub miniature tubes on ebay

[eliktronik]

Could anyone enlighten me as to what these could be used for??

[Hal]

very small guitar amps

(no joke)

[Mike Burgundy]

Go here:
http://tdsl.duncanamps.com/tubesearch.php
and see for yourself! Great resource.

[zachary vex]

Could anyone enlighten me as to what these could be used for??

who knows?  lotsa strange tube numbers going on there.

if you get into tubes smaller than the ones i use in the nano head, you'll find that the heater is tied to the cathode, which limits the wiring of cathodes in your circuit because they all are common to the heater supply.  the submini types are best, same size as my favorite 6021W.  there's a bunch of different gains available, as well as pentodes and triodes, singles and duals.  the subminis developed at the end of the fifties are based on downright amazing technology.  many of them are almost as long-life as solid-state devices.

[Peter Snowberg]

A historical note:

Those tiny little sub-minis were developed in England and the US during WWII for use in proximity artillery shell fuses. Some of the structures are actually strong enough to take the 30,000 Gs of acceleration which is what the shells see when fired out of a piece of field artillery.

The actual fuse circuits are still not very available to this day. Use of the shells was delayed for a long time in Europe because the Allied commanders didn't want to the Germans to see a fuse if a shell duded. Now that's secret.

The circuit involves an RF oscillator, an antenna, a firing capacitor, a battery (wet electrolyte cell activated by breaking a glass ampoule as the shell is fired), and a tube called a thyratron. Today we call solid-state thyratrons by the name SCR.

Firing the shell started up the battery, which then heated the tubes and started the oscillator running. That would transmit RF out of an antenna in the nose of the shell. A good SWR on the antenna (Standing Wave Ratio: a measure of how much power is going out the antenna) and good balance kept the transmitter outputting just below the thyratron's trigger threshold. As the shell got near the target, some of that energy would be reflected back to the antenna where it pushed the thyratron into triggering, dumping the capacitor into a primer, and then kaboom.

After the war, millions and millions of these fuses were made. The tooling was available so as soon as the technology was reduced in secrecy after the Korean War, the tiny tubes became the new darlings. There were even tube hearing aids getting made and then all the sudden the transistor became useable and the super sub-mini tubes went out of production almost overnight. The larger (but still tiny) tubes like the 6021 survived a lot longer and tubes were used in artillery fuses until the 80s.

Another useless tidbit.

We have the military industrial complex to thank for making the ZVex NanoHead possible today. I think that's called a peace dividend.

-Peter

[petemoore]

Fascinating 'of the day' state of the art technology !

[Ansil]

a batt operated stompbox preamp,  think, a real tube screamer.

[bwanasonic]

A historical note:

Thanks a lot Peter! Very nice historical note!

Kerry M

[zachary vex]

A historical note:

Those tiny little sub-minis were developed in England and the US during WWII for use in proximity artillery shell fuses. Some of the structures are actually strong enough to take the 30,000 Gs of acceleration which is what the shells see when fired out of a piece of field artillery.

The actual fuse circuits are still not very available to this day. Use of the shells was delayed for a long time in Europe because the Allied commanders didn't want to the Germans to see a fuse if a shell duded. Now that's secret.

The circuit involves an RF oscillator, an antenna, a firing capacitor, a battery (wet electrolyte cell activated by breaking a glass ampoule as the shell is fired), and a tube called a thyratron. Today we call solid-state thyratrons by the name SCR.

Firing the shell started up the battery, which then heated the tubes and started the oscillator running. That would transmit RF out of an antenna in the nose of the shell. A good SWR on the antenna (Standing Wave Ratio: a measure of how much power is going out the antenna) and good balance kept the transmitter outputting just below the thyratron's trigger threshold. As the shell got near the target, some of that energy would be reflected back to the antenna where it pushed the thyratron into triggering, dumping the capacitor into a primer, and then kaboom.

After the war, millions and millions of these fuses were made. The tooling was available so as soon as the technology was reduced in secrecy after the Korean War, the tiny tubes became the new darlings. There were even tube hearing aids getting made and then all the sudden the transistor became useable and the super sub-mini tubes went out of production almost overnight. The larger (but still tiny) tubes like the 6021 survived a lot longer and tubes were used in artillery fuses until the 80s.

Another useless tidbit.

We have the military industrial complex to thank for making the ZVex NanoHead possible today. I think that's called a peace dividend.

-Peter

that's really interesting information.  i have a schematic for the proximity fuse circuit you're talking about.  it came with my first few sample tubes.