>Hello all,
> My friend and I are contemplating a monoband amp based on the
>3CX3000A7 tube. A look at the Eimac spec sheet shows 410 Watts drive for
>AB2 Cathode driven.
>
>This doesn't seem very practical if you only have 100W of drive. On to grid
>driven AB2 specs. They show a very conservative output of 1.13KW with 11.5W
>of drive. Surely it can be driven a bit harder than that. The output figure
>for cathode driven is 7.26KW! What are the limiting factors of a grid
>driven amplifier using this tube. I mean if you are going to burn over 350W
>just to run the filament, surely you would want to see more than 1.13KW out.
>
>We would like to try and put 100W on the grid. What sort of input circuit
>would we need? Does anybody know the zero signal plate current? Would we
>need neutralising?
>
>Our alternative is to use a driver stage like a 4-250A or the like but we
>feel that it would complicate things.
>
>Any good ideas would be greatly appreciated.
>
>To any Aussies on this reflector, we know the max legal in Australia is
>400W pep. We would never put this thing on the air. We would just like to
>see if we can get it up and running. So spare us the lectures.
>
>73 de Alek.
>
>
Im not familiar with this tube but I cant see why it shouldnt put
out maximum power with the 100 watts drive, around 8 kW that is.
You can also increase plate voltage and run it GG and it will
put out 8 kW with 100-150 Watt drive. Forexample a 4CX5000 in GG
with 9 kV on plate will put out more then 7 kW with 150 Watt drive.
73 Jim SM2EKM
Ps: Or get a driver like an SB200 or something small like that.
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