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Identify this tube...__

knockbill

knockbill

Lunatic Member
I have a pair of these with almost no lettering on em,,, I put them in the freezer, and think I can make out 6A**
not sure what the other letters are tho... I'm thinking some kind of twin triodes, but its just a guess... The glass part is 3 3/8" high, and they have an octal base...
Thanks for any insight...
 

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Thanks, I believe you are correct,,, I'll try em in teh tester... Any audio use for these? They are GE tubes, however seems RCA developed them, and they aren't in my RCA manuals...
 
Found this quote on radiomuseum site... Guess I need to do a little more research...
"Used as a regulator tube in dc power-supply units, as a booster tube in the scanning circuit of television receivers, and as a push-pull class A output tube in high-fidelity audio amplifiers."
Thanks for teh replies...
 
That's what I've been reading... There are presently Russia made 6H13C/6AS7s (Winged C) and others are making them...
Time to look for a schematic, I think!! Little headphone amp may be interesting...
 
RCA promoted the 6AS7G as an "audio tube" in RC-18 (1956-1957) and provided audio ratings and suggested operating points in the data section in addition to TV and regulator apps. Intention was a traditional OPT coupled design. They even provided a complete design for a High Fidelity PP integrated amp in the "circuits" section. This after an RCA engineer co-authored an article in "Audio Engineering" (6/54) describing a transformerless power amp featuring the 6082, a 26.5V version of the 6AS7.

While convenient because it contained two power triodes in one envelope, it was extraordinarily difficult to drive because of the low gain and never caught on as an audio output tube and almost disappeared into tube obscurity...until it was rediscovered as useful in "modern" OTL designs.
 
Steve O said:
RCA promoted the 6AS7G as an "audio tube" in RC-18 (1956-1957) and provided audio ratings and suggested operating points in the data section in addition to TV and regulator apps. Intention was a traditional OPT coupled design. They even provided a complete design for a High Fidelity PP integrated amp in the "circuits" section. This after an RCA engineer co-authored an article in "Audio Engineering" (6/54) describing a transformerless power amp featuring the 6082, a 26.5V version of the 6AS7.

While convenient because it contained two power triodes in one envelope, it was extraordinarily difficult to drive because of the low gain and never caught on as an audio output tube and almost disappeared into tube obscurity...until it was rediscovered as useful in "modern" OTL designs.
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Aren't the cathodes tied together, or is that another tube I'm thinking of? So many good tubes are being discovered now, look at the 3DG4, they must have used those in Sherman tanks or something. :)
 
Well, the posted links show some ideas,,, may be worth trying a channel on a breadboard just for S&G,,, Learning is Fun!
I also have some 829Bs, can build a PP amp in one bottle with those also...
 
jaymanaa said:
Aren't the cathodes tied together, or is that another tube I'm thinking of? So many good tubes are being discovered now, look at the 3DG4, they must have used those in Sherman tanks or something. :)
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They are separate,,, I was hoping they would be a 6SL7/6SN7 replacement in a globe bottle just for looks, but it don't seem that's the case...
These were in a huge box of G tubes, mostly 1625s, 807s, and 6BG6s, and lots of cool rectifiers, 6R4s, 6AR4s, 5U4s, 5Y3s, I grabbed at a hamfest last week for next to nothing....
 
I have a couple of those myself. Always had meant to build a headphone amp around them, but I don't actually own a set of headphones so there was never the motivation to do it. Seems like it would make a nice tube for it though if you had high impedance cans.
 
Just tested teh pair I have, seem to be fine... Going to build a SE stereo amp using one of them and a 6sn7 driver... this one needs an OPT, tho... don't know if I have a 600R OPT in stock,,, we'll see what happens...
 
knockbill said:
Just tested teh pair I have, seem to be fine... Going to build a SE stereo amp using one of them and a 6sn7 driver... this one needs an OPT, tho... don't know if I have a 600R OPT in stock,,, we'll see what happens...
Click to expand...

Just tacked this together, its kinda of a cool looking tube... Still have to find a suitable OPT for it...
 

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600 ohm is awful close to what PA speakers run. If you can find a suitable line matching transformer and cap-couple it to keep DC off the transformer it might work out OK for small coin.
 
The 600R is on teh secondary isn't it? I have a bunch of 70V transformers, but they are 70V to 4 thru 16R I think?? never worked on PA speaker systems, other than that Bogen/Challenger... but I had to scrounge an OPT for it...
 
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