[Amps] Question re GU-74B grid current

[Val]

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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