[Amps] 813 efficiency

[Bill Fuqua]

   One tube in the 813 class never mentioned that is real cheap because 
practically very few
amplifiers or transmitters used them is the 4E27A Pentode.
It has 125 watts plate dissipation and fits into a 813 socket.
    Anyone out there use one in grounded grid operation? Should be similar to
813's I would guess.

It just dawned on me the designation used in that tube series.

3B28 is a diode
2C40 is a triode
4D32 is tetrode
4E27A is pentode
the letter is describes how many element it has Obviously there is not an
A designation.
Wonder who came up with that one. Don't see a pattern for the numbers.

73
Bill wa4lav


At 11:09 AM 2/23/2013 -0500, Carl wrote:
>For about the same money there are still many 4-250A and 400A's available.
>
>Carl
>KM1H
>
>
>
>>Hi Guys,
>>
>>It absolutely gobsmacks me how some guys in this hobby would rather 
>>whip-out the ol' VISA card & spend literally HUNDREDS on power amplifier 
>>tubes, when the lowly ol' 813---paired with some twins, of course!---will 
>>do the job as well, and at an absolute FRACTION of the price...
>>
>>Sure the tube has high interelectrode capacitance, & has been around 
>>since before WW2: but so what? It's nothing that a bit of 21st century 
>>technology can't master...and who cares about age? After all, I myself am 
>>60 years old here, & hardly consider my existence to be "redundant"! Hi Hi
>>
>>~73~ de Eddy VE3CUI - VE3XZ
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