Someone (sorry!) said:
>> >I also note that Svetlana now makes an 812 tube. Not sure how they
>> >compare to 811's, but recall they are a hotter version of the same.
>> the 812 is similar, but has a substantially lower Mu.
>I was really thinking of the 813. Don't think Svetlana is making
>that, though.
Yes, 812 would be hard to drive(lower gain). 813 is beam power tube (tetrode),
not triode. Maybe it could be connected grid to screen and run in triode
mode, although
it may be easy to overdissipate the grid in such a circuit. Is there
experience here with using 813 in triode connection?
I have an old power oscillator (sort of an ultrasonic driver) that I got
from GSA auction years ago, and it has a pair of 813's in it. It drives 10
Khz at 300 watts or so, and had a nickel magnetostrictive transducer at one
time, to separate blood cells! (according to the paperwork from Raytheon).
Since it is in a rack chassis and has the screen and plate power, I was
going to do an HF amplifier with the thing, many moons ago. now it sits in
dust and bugs in "the shed", next to the diathermy machines (another
subject!).
John
K5PRO
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