[Amps] Low power output from 4-400A linear

[Steve Thompson]

Bruce Lanning wrote:
> Several years ago, I built a GG amplifier using a pair of 4-400A. The grid 
> and screen are grounded at the tube socket.
> 
> I feel that the power out is quite low. Below are some of the operating 
> parameters:
>  Measured power out: 855 watts
>  Power input: 1216 Watts
>  Ep:3200 Volts
>  Ip: 380 Ma.( at max output)
>  Ig: 250 Ma.
>  Eg: Bias 00
>  Static Ip: 120 Ma.
> 
> I am using the B&W Pi-network, model 850A output tuning inductor
> .
> I have checked the tube filament pins for a poor solder joint.
> They both looked OK, but I resoldered them to no avail.
> 
> Maybe someone out there could throw some light on my problem, or if I even 
> have a problem...
Efficiency and grid current are both high - suggests it's saturating 
hard so you could just try loading it heavier. You'll lose some gain, 
but should get more output if you crank up the drive.

Steve