>Me and my mates at the LA8G club stn have got our hands on a brand new
>3CX2500 F3 / 8251.
>
This is a medium Mu triode. It is intended for (non-linear) Class C
service. In Class AB1 grid-driven linear service, the available power
output would be small indeed because not much peak anode current is drawn
with 0v on the grid. In Class AB2 cathode-driven linear service, due to
lack of Mu, considerable RF driving voltage/power is needed at the
cathode. IMO, it would take roughly 1000w to fairly drive a 3CX2500F3 in
cathode-driven service.
>Our intention is to build a rugged 2kW output amp for HF contesting,
>particularly the lowbands are interesting.
>
>As this tube have HV supply max ratings 6kV/2.5A, our wishes should be
>possible to achieve..!
Agreed, provided you can come up with the drive.
IMO, a Svetlana 8171 tetrode would be a better choice, Johnny. The 8171
is Much easier to cool. The drive requirement is 150w. The realizable
gain is roughly 10db in Class A and 20db in Class AB1. To switch between
Class A and Class AB1, one merely adjusts the microphone gain control.
Rich---
R. L. Measures, 805-386-3734, AG6K
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