>
>Eimac short form catalog gives typical operation in AB1 as 300W o/p with
>2000Va and 400Vg2. Seems to me (and I have used a lot of 4CX250 types)
>that 600W from a pair is all you can really expect and maintain linearity.
>Of course if linear operation is not required - eg for CW - then the tubes
>can be driven harder, more towards Class C, and then you can expect a
>little more out. But the maximum grid dissipation is only 2 Watts so that
>could be a bit risky!
>
True enough, John, however when the grid is driven from zero grid current
in AB1 to substantial grid current in Class C, input SWR rises abruptly -
and that causes grief for the radio that is used to drive the amplifier.
Compared to Class C, Class AB1 costs one about 1/5 of one "S" unit on the
"S" meter. In my mind the bottom-line is that Class C has too many
trade-offs. . If one needs more suds, 'tis better to use a larger tube
in AB1 than to beat up a less-capable tube in Class C.
- later, John
Rich...
R. L. Measures, 805-386-3734, AG6K, www.vcnet.com/measures
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