> My SB 200 produces 700 Watts PEP, with about 50 Watts PEP
> drive, and my SB
> 220 produces about 1.5 KW PEP (both amps on 20 meters)
> with about 80 Watts
> PEP drive.
I've never seen a pair of 3-500Z's driven with 100 watts
produce 1500W PEP ***on an accurate power meter*** with only
3000V on the anode.
Neither did B&W. Neither did Viewstar. That's why they ran
3500V plus on the anodes. Every manufacturer has fought this
gain problem.
It takes about 3400 volts or more to get 1500W out with 100W
drive.
This isn't to say a pair of 3-500Z at 3000V won't show 1500W
PEP on some wattmeters. I've just never seen that power on
accurate meters.
All of my SB220's, even with the grids grounded, only make
around 1200-1300 with100W drive on a known accuracy meter.
By the way, a typical o-scope is one of the least reliable
common ways to read power. First, scopes have passband
ripple. They are designed of good response to a stepped
waveform, frequency response flatness (or lack of ripple) is
secondary. Second, they are susceptible to common mode on
probe leads. Third, they don't store the absolute peaks
unless you have a storage scope and are lucky enough to
catch the peak. Fourth, any error they do have is compounded
by the fact power is a square of the measured voltage, so
the error is squared. Fifth, they are load resistance
critical.
RF power meters with peak storage circuits are the best way
by far.
73 Tom
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