[Amps] How to read the 3-500Z spec sheet?

[Bill Dzurilla]

Hi,

I'm looking at the spec sheet for the 3-500Z at
http://www.scottbecker.net/tube/sheets/088/3/3-500Z.pdf

At the top of the second pages, it gives numbers for various parameters at different levels of high voltage (3000, 2500, 2000, and 1500).  Are these voltages at load or no-load?  And how do Single-Tone DC Plate Current and Peak Envelope Useful Output Power correlate with key down plate current and output?

The reason I ask is because I picked up a homebrew 6m amp with a single 3-500Z, which uses a power transformer from an SB-200.  Key down power output is 400w.  Assuming the amp's meters are accurate, no-load plate voltage is 2300v, and plate voltage under full load is 1950v.  Plate current with no drive is 100ma and plate current with full drive is .52a.  About 40 watts of drive produces the full 400w out.  Further increases in drive, up to 100w, do not increase output.

Judging from the spec sheet's 2000v table, my guess is that the amp is performing as well as it can with this power supply.  I know that a converted AL-80B with a single 3-500Z can produce 900w or so on 6m, but it has a 3000v p/s.

Do you think it would be OK to run this amp at the full 400w in WSJT (continuous carrier) modes?

73, Bill NZ5N