[AMPS] PA Recommendation Wanted

[Rich Measures]

>At 11:28 AM 6/8/97 -0700, you wrote:
>>>Rich Measures wrote:
>
>>Trying another door.........OK, I don't touch the screen V adjust.  
>>However, what can can go wrong if one uses the grid bias V adjust to 
>>adjust ZSAC in Class AB1? 
>> The benefits of using the screen V adjust to set ZSAC are:
>>1.  You wind up with the highest screen V--i.e., more RF output. (the 
>>Esc^3/2 power law)
>>2.  You don't run the nasty IMD risk of drawing grid current.  
>
>However, by adjusting the screen voltage one changes the gain of the tube 
>and risks excessive screen dissipation. 

 Mr. Subich's scenario would be possible IF the operator did not know how 
to adjust the tune and load controls in a Class AB1 amplifier, AND the 
amplifier's designer FORGOT to include screen protection in the design.   

> That is, screen voltage too low 
>and stage ouptut is low with attendant overdrive and IBM ... screen voltage 
>too high and the screen begins to act like the plate and show excessive 
>dissipation.  
>
I heard that they were branching out, but I didn't know IBM was into high 
ouptut RF amps.  
Rich---

R. L. Measures, 805-386-3734, AG6K   


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