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.
--------------------------------
>
> Greetings,
>
> After digesting the material that I have collected and the responses
> from an earlier post (tnx, Skipp), I think the best way to go for my
> homebrew amp is to run the 4-400's in class AB grounded grid.
>
> I have dug up a couple of construction articles. One is from the
>1982
> ARRL Handbook. In chapter 6, it describes "An Economy 2-kW
>Amplifier"
> that uses these tubes grounded grid. It doesn't, however, have a
>tuned
> input network.
>
> I'd like to add one. But before I do, I need to know what the
>approx.
> input impedance is for a pair of 4-400's in grounded grid. If it
> matters any, I plan to run 3000 ~ 3500v on the plates.
>
> Thanks in advance!
>
> 73,
> Charlie N9CO
>
> --
> FAQ on WWW: http://www.contesting.com/ampsfaq.html
> Submissions: amps@contesting.com
> Administrative requests: amps-REQUEST@contesting.com
> Problems: owner-amps@contesting.com
> Search: http://www.contesting.com/km9p/search.htm
--
FAQ on WWW: http://www.contesting.com/ampsfaq.html
Submissions: amps@contesting.com
Administrative requests: amps-REQUEST@contesting.com
Problems: owner-amps@contesting.com
Search: http://www.contesting.com/km9p/search.htm
|