Jan.E.Holm@telia.se wrote:
>
> With 100W drive and 3kV on a pair of 4-400´s it might
> be a problem to get 1500 out, better run 4 kV on plates.
> I have a 3 tube 4-400 amp 10 - 160m and it runs excelent.
> After 20 years of service it still runs full output and
> the tubes wasn´t even new back then, I run slightly less
> then 4kV on them and they are GG. If you have the hardware
> for a 3 tuber that´s the way to go.
>
> 73, Jim SM2EKM
>
> PS: You can use the same tuned input as a SB-220 (or similar)
> uses and just tweak it.
Hi Jim,
Thanks for the reply. Your idea of a 3 holer sounds neat. I wasn't
expecting to get more than 1200 watts out from a pair of gg 4-400's. I
think that's about all you can do assuming 60% efficiency in class AB
without exceeding their plate dissipation.
I'm curious what values you used in your tank circuit. The problem that
I see with 3 tubes is the increased Cout (plate to gnd) that the pi-L
network will see. It's probably not a problem on 160 through 40, but
the Q of the network must be pretty high on 10m.
BTW, the bottles that I will be using are the pulse rated version of the
4-400, the 4PR400A (8188). I have 5 of them.
73,
Charlie N9CO
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