[Amps] Parasites (parasitics)

[2]

> ...>> >>
>> >> **  loading the parasitic after the fact is not possible.  The trick is
>> >> to reduce gain at the anode's specific damped-wave ringing frequency.
>> >
>> >Probably a dumb question.. in 4-1000 amps the "parasitic" or oscillation
>> >that occurs was in the 90 or so MHZ region.  It seemed very easy to
>> >cure that by moving that "resonant" freq out of the VHF "high gain "
>> >region ( or is it called self resonant freq of the tube ?) down to a
>lower
>> >freq just by inserting a coil of wire in the plate lead.  No resistor
>needed
>> at
>> >all, just keep the "resonance" above 35 MHZ or so, so that it did not
>affect
>> 10
>> >meters.
>> >What am I missing that this is not used more ??
>>
>> **  How much L was added?
>> Was it grounded-grid - or grid-driven?
>>
>Sorry about that .. did not measure the L.. but 3 turns of number
>12 wire 1inch diameter is what memory tells me.  Grounded grid.
>Eimac plastic sockets.  Was very repeatable in all the amps I built
>and several others that had problems.

**  tnx, Merv.  With g-g config, the 4-1000A's pesky screen resonance at 
c.25MHz would not cause much a problem since the control-grid would still 
shield the input from the output.  How much anode ps potential?

>Covered 160 to 10.. (with a shorting bandswitch a must I must add)
>Merv


-  R. L. Measures, a.k.a. Rich..., 805.386.3734, AG6K, 
www.vcnet.com/measures.  
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