>
>
>> Hi Douglas this is a very bad idea. The IMD performance of any tetrode
>> is dependant on good screen voltage regulation. The dynamic regulation
>
>
>That 's true.
>
With good quality zeners, the screen regulation is ok. Cheap zeners are
not a bargain.
>> of the plate supply is pretty bad and this obviously causes problems
>> with screen regulation if a string of zeners are used.
>
>Why? There is no reason it should cause problems if you wrap
>around the zeners with few transistors.
>
>The series resistance of a string of zeners might be too large
>compared to the dynamic resistance of the screen, but if you have
>enough voltage feeding the shunt regulator (at least twice the
>screen voltage under full load) to properly current limit the screen
>the zeners won't waddle around enough to hurt.
>
>Just don't use zeners as the shunting device. Use some transistors
>so the current gain lowers the shunt impedance. That way you can
>use low power zeners, and regulation is good.
>
Unsliced bologna. A string of 5w / 20v zeners can handle anything up to
a pair of 4-400Cs (800v).
>
>
>
>
>
>
>
>
>John Nelson
>> GW4FRX wrote some excellent articles on this in the 80s.John frequents
>> this forum so he may wish to comment.Meanwhile try this link for a
>> solution http://www.ifwtech.com/g3sek/boards/tetrode/tetrode-1.htm and
>> some background info.
>>
>> Regards
>>
>> Conrad Farlow G0RUZ
>>
>>
>> --
>> FAQ on WWW: http://www.contesting.com/FAQ/amps
>> Submissions: amps@contesting.com
>> Administrative requests: amps-REQUEST@contesting.com
>> Problems: owner-amps@contesting.com
>>
>
>
>73, Tom W8JI
>W8JI@contesting.com
>
>--
>FAQ on WWW: http://www.contesting.com/FAQ/amps
>Submissions: amps@contesting.com
>Administrative requests: amps-REQUEST@contesting.com
>Problems: owner-amps@contesting.com
>
>
- Rich..., 805.386.3734, www.vcnet.com/measures.
end
--
FAQ on WWW: http://www.contesting.com/FAQ/amps
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Administrative requests: amps-REQUEST@contesting.com
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