Mic Kaczmarczik's TubeInformation - The Blue Guitar

ut it has no "getter", like a 6550A. But they run 3KV
at 115 ma as a Class C RF amp. I was told they were pumped
for like 24 hours for a much better vacuum than what one would see
in a normal recieving tube.
This makes sense. Look in a power tube like a 5881, you'll see a
blue glow which to me looks very similar to the glow I see
with 2050 thyratrons, ie: the less inert gas there is left,
the less chance of an arcover.
3.Quality control. Compare a 4-65A to a 4PR65A.
They look the same, but 4PR65A is pulse rated
(from memory, specs no longer listed in the Eimac catalog)
for use with a 10KV supply. I know 4-65A won't work,
in place of 4PR65, I sold some (back when they were a
bit more plentiful) cheap to place that makes flight simulators,
where they promptly failed. (their idea, not mine!)
Since I couldn't discern the
differences by eyeballing, I'd assume even
more vacuum pumping & tighter tolerance control.
BTW: a cousin of the 4PR65, the 4PR60C, does
20KV, 1.25KV screen, and peak current of 18 amps,
peak power of 337KW. It's only 6 inches long, but
has a ..egads.. 54 watt filament!
4. Duty cycle. Hmmm, perusing my Eimac book
I see the Y-141 planar triode. 59 mm long, weighs
70 grams. Typical operating parameters: 5 KV anode,
plate current 4 amps. Output power, 11 KW.
Duty cycle, .001 %.
5.Distance between pins. Note the differences
between 807 & 6L6 re voltage rating. Again, back to
the socket-cracking problem, as noted above.
6.Plate material, at least on glass recieving tubes.
I have a T-40 Taylor here. Looks just like a '50,
but has carbon anode and plate cap.
Voltage rating, 1500 volts.
>I know they can take big K's. Has anyone actually got a case of tubes
>dying from too many K's?????
Well, it's lot easier to blow up gas rectifiers than vacuum tubes...
>Lacking the equipment to do proper tests, I wonder if anyone out there
>has done proper lab tests on 6L6's or EL34's to see what they really
>will take......
In terms of terms of plate dissipation and max cathode current,
you probably have a pretty good idea already.
Guys that build illegal CB kickers with tubes really go
nuts on that angle, one customer with a *mobile*
(musta had a double alternator) tube kicker reported
that he was running 40KG6's, at 1000V, plates glowing
with the mic keyed. Yow!
I'll bet it has been done. What's more, I'd say no tube mfr
in the old days, at least, would've shipped boxcars full of
tubes to OEM's without extensive testing.
Ned Carlson, Triode Electronics, Chicago, IL http://www.triodeel.com
Open 12:30-8 PM CT, 12:30-5 PM CT Sat Closed Wed
ph:773-871-7459 fax 773-871-7938 "where da tubes are"
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