[Amps] 3-1000Z Filament Voltage Question

[Dennis Sokol]

I have a BTI LK-2000 using a 3-1000Z operating on 160. I can get 1250 watts out with 2700 volts and 750 ma key down. The tube seems to be limited in current draw. I have seen more power out at a different QTH with higher line voltage.

I have measured the filament voltage at full load to be 7.08 volts.
This is a bit low from the spec of 7.13 to 7.87 volts. Is the low filament voltage a possible cause of reduced power out?

There is a 208 volt tap on the filament xformer but I would have to put in a dropping resistor in the primary to bring the voltage down to 7.5 volts.  Is it worth the effort? Am I hurting the tube with the lower filament voltage or am I extending the life?

Thanks and 73,
Dennis W0JX Milan, OH