[Amps] How do I determine Class

[R.Measures]

On Aug 31, 2004, at 8:32 PM, Vic Rosenthal wrote:

> Jim Isbell wrote:
>
>> On pages 202-205 of the 1956 "Radio Amateurs Handbook"  (ARRL) there 
>> is an amplifier described called "Parallel Tetrodes in a High Power 
>> Amplifier"  How do I, from that description and schematics etc., 
>> determine in what class the amplifier is operating?  And what is a 
>> National MB-40-L?  I assume its no longer available but also assume 
>> that it can be reproduced.  This looks like just what I need for a 
>> linear to go with my Viking Ranger to add some boost to the signal 
>> when needed. AND still be contemporary period.
>
> The class of operation is determined by the operating conditions
> (element voltages and drive).  A pair of 4-250As, grid driven, with 3KV
> on the plate would require about -180v bias, 500v on the screen,

To take full advantage of the emissive ability of the 4-250A's cathode, 
c. 800v is required on the screen.

> and...

Richard L. Measures, AG6K, 805.386.3734.  www.somis.org