[Elecraft] KPA500 Voltage range?

[Andy Durbin]

"My kpa500 has the taps set to provide 71-72 VDC no load and drops to 60 at 500 watts."

Do you know how your house line input voltage varies?   Mine can be as high as 122 and as low as 118 and the local transformer is less than 50 ft from my house.

 I see unloaded KPA500 voltage over 80 with tap selected to keep loaded KPA500 voltage at or above 60.   If your loaded voltage does not drop below 60 for all bands, all antenna loads, and all used output powers, I see no reason to change the tap.  Band, loading, and power output all have a very significant influence on efficiency, PA current, and voltage drop in the PA HV supply.

Spot check values:
Line voltage 122.0
Unloaded HV 81.4
TX 500 W, 6 m band, SWR 1.15, HV 60.3

Andy, k3wyc