On 21 Oct 2003 at 14:25, peter.chadwick@Zarlink.Com wrote:
< snip >
> If looking for low price, you probably can't get cheaper than using surplus
> 4CX250Bs, even though you have to blow them fairly hard. 4 of them will
> give a kW out with reasonable linearity: it may well be possible to put NFB
> on to improve linearity while using up some of the excess gain that there
> would be with a 100 watt driver.
Don't forget the 4x150a! A fellow at Eimac told me years ago that you could
run
them in the '250 applications, SO LONG AS YOU KEEP THEM COOL.
> (I don't believe they're any good in G-G service)
Probably fine in G-G service, if you use the proper grid supply voltages. Just
hooking
the screen to the control grid and running them G-G is a very bad idea, though.
Control grid current is a splatter-generator and a tube killer for these and
similar
tetrodes.
73,
George T. Daughters, K6GT
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