Thats being rather polite about it (-;
Carl
KM1H
71% overall efficiency is remarkable for a class AB1 amplifier.
On 10/22/2012 12:10 PM, Val wrote:
Jim,
ACOM1000 and ACOM2000A are without doubt the most popular amplifiers
based on GU74B. Many thousands of them are working under the following
conditions at1000W output:
Plate 2350-2400V
Screen 340V
Anode current 510-580mA
Bias between -45 and -65V for 220 mA idling current (the EBS keeps the
bias between -65 and -75V for idling current of 70 mA when no RF drive)
Normally the grid current is well below 10mA where the grid protection
trips.
73, Val LZ1VB
Could somebody advise me as to the resting plate current and operating
ctrl
grid bias voltage they are using on a GU-74B (plate voltage is 2500V,
screen
grid 300V)? Also, does the tube draw grid current? I realize that in
AB1, no
grid current should be drawn, but the tube characteristic curves predict
about 15mA grid current at full output (1000W output, 600mA anode
current
(per tube) and 250W resting dissipation. I am interesting in what
builders
are actually getting, and not information from data or spec sheets.
Tnx and 73,
Jim W8ZR
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Vic, K2VCO
Fresno CA
http://www.qsl.net/k2vco/
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