[Amps] output of SB220 typical TSPA

[Tom W8JI]

> Joe,what was the filament voltage with that kind of line 
> input? Excessive
> filament voltage allows more than normal emission with 
> thoriated tungsten
> fils...At least for a while! 73, Jim K7RDX..

Jim,

A single tube will easily make 1200 watts or more  with 
enough drive at 3000 volts, and you don't have to run the 
filament extra hot to do it.
There isn't any doubt at all people are seeing 2kW or more 
from a pair when they bang them with 150 watts or more at 
3kV or more.

The problem is with claims that a pair in g-g run 1500 watts 
or more out with 100 watts of drive and about 3kV on the 
anode. It really won't happen, even if you put 10 volts on 
the filament. The problem is power gain, and the gain is 
largely set by the ratio of cathode driving impedance to 
anode load impedance in a g-g amp. The only way to get more 
gain is by running more HV so the anode impedance is higher.

73 Tom