[AMPS] 4-1000A Project

[Tom Rauch]

Hi Bill,

> Bill Orr stated in his article on Tetrodes used in grounded grid
> amplifiers (about 170 watts) but at 5 or more KV it is less than 70

I agree with that.....

> watts for full output and about 50 for full gallon (1500 watts). Also

.....but that seems overly optimistic. I could NOT get 1500 watts 
out with any cathode driven 4-1000A with 100 watts of drive unless 
HV was nearly 6000 volts.

A 3CX1200 has a lower driving impedance, and more gain, and 
barely makes 1500 watts at 3300 volts with 1000 watts of drive.  

> a 1KVA variac is small not only due to the fact that the plate input
> power for 1500watts output CW would be over 2KW but that the current
> drawn by the power supply is many times the RMS value for a Capacitive
> input filter. Not so much a problem with a inductive input filter.

Yep, I'd use that 1kva variac for a filament supply. It's too small for 
an anode supply even in a 500 watt output PA.
73, Tom W8JI
W8JI@contesting.com 

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