I am guesstimating that it is around 4 watts, I have not been able to find any data sheets that state what it is🙁 If anyone knows what the value is I'd love to know🙂
I don't recall seeing any dissipation data for 01A and 26 either, maybe also 10Y. Anyone have those data?
Summary of 5V Triodes
I put this together a few years ago. But don't recall finding any data at all on plate dissipation max. Some may find the rest of the information useful.🙂
I put this together a few years ago. But don't recall finding any data at all on plate dissipation max. Some may find the rest of the information useful.🙂
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The 10 & 10Y are not the same as the 71A at all. A physically larger tube with a much larger heater. The 10Y has a low loss base made for RF use.🙂
Of course not the same.
Information was provided in response to query about Type 10 in post #4.
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I have often wondered about PdMax of 01A, 12A and 71A, filament is the same and plate structure is the same size but haven't seen anything so far in print form detailing max ratings.
Information was provided in response to query about Type 10 in post #4.
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I have often wondered about PdMax of 01A, 12A and 71A, filament is the same and plate structure is the same size but haven't seen anything so far in print form detailing max ratings.
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I've always figured the designers of these old tubes were at first working on detting more current from the filament coating and getting higher voltage capability - perhaps that means a better vacuum? So they quoted the maximum current and the maximum voltage. There was thus no point in specifying max power dissipation, since no other acceptable operating point could have greater dissipation.
Incidentally, the Type numbers were not consecutive (again, to the best of my knowledge):
01: from GE, 1920, 01A 1922
11, 12 Westinghouse, 1922. The beginning of oxide emitters?
12A Westinghouse, 1925
71A Westinghouse, November 1926
26 (Not sure) 1927
50 Westinghouse, May 1928
45 Westinghouse, March 1929
My speculation is that Westinghouse copied the 01A but with an oxide filament, which doubled the transconductance, and called it the 12A. Once that was done, they just traded mu for plate resistance, perhaps by changing just the grid pitch, to get the 71A. Both have the same heater specs, same transconductance and the same maximum voltage. Then went back to the 12A and put in a low-voltage filament, calling it the 26. With that experience, they went for low-mu power with the 50 (filament power and maximim voltage match the 10 made by GE) in 1928 and the 45 a year later.
Incidentally, the Type numbers were not consecutive (again, to the best of my knowledge):
01: from GE, 1920, 01A 1922
11, 12 Westinghouse, 1922. The beginning of oxide emitters?
12A Westinghouse, 1925
71A Westinghouse, November 1926
26 (Not sure) 1927
50 Westinghouse, May 1928
45 Westinghouse, March 1929
My speculation is that Westinghouse copied the 01A but with an oxide filament, which doubled the transconductance, and called it the 12A. Once that was done, they just traded mu for plate resistance, perhaps by changing just the grid pitch, to get the 71A. Both have the same heater specs, same transconductance and the same maximum voltage. Then went back to the 12A and put in a low-voltage filament, calling it the 26. With that experience, they went for low-mu power with the 50 (filament power and maximim voltage match the 10 made by GE) in 1928 and the 45 a year later.