New russian tube based superhet runs on 9v

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New russian tube based superhet runs on 9v

Postby Doug Coulter » Sun May 29, 2011 12:57 pm

For those who appreciate the truly arcane -- and innovative, see this link friend Joe Sousa sent me the other day:
http://www.radiomuseum.org/forum/sputni ... radio.html

This is a full superhet AM radio made from Russian rod-grid beam tubes, a very bizarre type of construction (no grids!) that uses beam forming and steering with rods instead of grid wires. This opens up some interesting unconventional circuits, and Joe took this one all the way. For the places where odd higher and negative voltages are needed, he uses the local oscillator to generate them for the rest of the circuit.

He's sent me a few of these, and I have a use for them in mind. Few other things could work as sensitive in-tank preamps for weak signals and live in a fusion device. But these will...
Posting as just me, not as the forum owner. Everything I say is "in my opinion" and YMMV -- which should go for everyone without saying.
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Re: New russian tube based superhet runs on 9v

Postby Joe Jarski » Mon May 30, 2011 2:39 pm

Great link! Interesting tube construction - I bet those little guys are pretty durable. I'm going to have to revisit that site a few times. There is a lot to read and I'm still stuck on studying the tubes - haven't even gotten to the radio yet. 8-)
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Re: New russian tube based superhet runs on 9v

Postby Doug Coulter » Tue May 31, 2011 10:53 am

Joe Sousa is an engineer's engineer. We met over our shared interest in Philbrick opamps and lore. I like the way he thinks -- sideways. He maintains a site for Philbrick information too. As you can see, he does nice work, and documents what he did throughly. Though he designs chips for a living, he putters with tubes, and like to use them in all sorts of odd connections rather than the examples you see on the data sheets. In the case of these particular Russian tubes (from MIG avionics) you can use the rod grids either tied together as a grid, or differentially as a way to steer the electron beam around inside the tube and he's taking advantage of that in the above radio.

I saw a design he did for a low voltage tube audio amp that used tubes far from the data sheet specs. To get an audio output tube to work at low voltage, he made a Darlington connection with another tube and drove the grid of the output tube far positive to make it draw current even well below the supposed lower limit of plate voltage. Normally a no-no (because you can burn up the control grid doing that and for other reasons), but it worked fine.
Posting as just me, not as the forum owner. Everything I say is "in my opinion" and YMMV -- which should go for everyone without saying.
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Re: New russian tube based superhet runs on 9v

Postby Kirk McLoren » Sun Mar 09, 2014 10:23 pm

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Re: New russian tube based superhet runs on 9v

Postby Doug Coulter » Mon Mar 10, 2014 11:10 am

Yes, very much. Thanks! You obviously "get it". I'll send Joe a copy too, and maybe we can get him posting here again...at the very least, I'm sure he'll appreciate it. I will stick this in our library as well, for future reference, once I get the chance.
Still adding the new guys - a few a day, because it's about half adding new guys, and half wiping out the random trash who sign up in an instant when registration is open so I can validate the ones we want as the board admin. I have no clue why we're so attractive to the 'bots (I can almost understand the random crazies looking for platform to spew conspiracy and pseudo-science, since everyone else ejects them too), but it seems we are "hot" right now.
Posting as just me, not as the forum owner. Everything I say is "in my opinion" and YMMV -- which should go for everyone without saying.
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Re: New russian tube based superhet runs on 9v

Postby Doug Coulter » Thu Mar 13, 2014 4:36 pm

Joe sez:
I read the low voltage triode article. It is all OK, although the
general notions of starved operation, which means low plate current
at high voltage and high mu, is not what is at work here. But he does
acknowledge the usual definition. This is simply low plate voltage
operation and the curves suggest less mu than usual. Perhaps the best
thing about this is that it makes it possible to play with audio and
tubes at low voltages. He also did a very good job with dealing with
contact potential at the grid, thus coming to the correct conclusion
that the 12AU7/ECC82 is best. One thing he ought to try to knock down
the contact potential is starving the heater; he certainly only needs
a tiny portion of the available space charge, and right now the
excess space charge is flooding the grid.
By the way, thanks for the kind words in your forum.
-Joe
Posting as just me, not as the forum owner. Everything I say is "in my opinion" and YMMV -- which should go for everyone without saying.
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