>
>I pick up 4 new 4CX250BM valves at a hamfest recently. Does anyone know a
>source of a design using 4 valves for the HF bands? Presumably they can
>simply
>be operated in parallel
? For linear amplifier service, I would put a separate vhf supp. on each
anode, use maximal screen and anode potentials, put around 1 ohm in
series with each grid, and terminate the grid with 12-ohms fed through a
bifilar input b-b matching transformer. I doubt that independent bias
adj. on each would be needed, however, checking on individual zsac is
easy if there is a small amount of (low-L) R between each cathode and
gnd. A small amount of L will probably be needed on higher bands to
cancel the grids' C.
- later
Rich...
R. L. Measures, 805-386-3734, AG6K, www.vcnet.com/measures
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