Amps
[Top] [All Lists]

[AMPS] Is screen potential important?

To: <amps@contesting.com>
Subject: [AMPS] Is screen potential important?
From: 2@vc.net (measures)
Date: Thu, 30 Mar 2000 12:14:00 -0700
>
>Rich said:
>
>" With any tetrode,  to obtain linear suds, one can vary the grid v. Or one
>can vary the screen v. -- but Not at the same time.   In other words, When
>the grid potential varies, the screen potential must be fixed, and vice
>versa. "
>
>WHY NOT?
>
It's not polite to shout. 

>For a linear amplifier to result, the plate current simply must be linear to
>grid drive.  

ok

>We know from the Eimac curves of the 8171 that gain changes
>with screen voltage.  

The 8171 is quite similar to the 4-125A, the 8973, and other tetrodes.  

> Logic tells us that for any particular grid drive,
>there must be a certain screen voltage that will yield the desired plate
>current (to achieve linearity).  

.  There is no certain screen voltage.  This screen potential is always 
1500v unless you need to make less suds.  .  My guess is that c. 250v on 
the screen would be needed for 1500w out.

>  That necessary screen voltage will vary with drive, 

not in a linear amplifier. 

> but can be plotted and will be a curve.  If the G2DAF design
>achieves the desired curve, then that condition of linearity will result.
>
>Your statement is simply wrong.
>
any port in a storm

>There are a number of other factors that would remain, even if the original
>G2DAF design satisfies this requirment of linearity.  

''this requirement of linearity''  does not fly. 

>......
>
>If any amplifier is to be rejected, it ought to be rejected for the right
>reasons.  This is called science.

No amplifier has been rejected.  Some generate less splatter than others. 
 
>
later, Colin

-  Rich..., 805.386.3734, www.vcnet.com/measures.  
end


--
FAQ on WWW:               http://www.contesting.com/ampsfaq.html
Submissions:              amps@contesting.com
Administrative requests:  amps-REQUEST@contesting.com
Problems:                 owner-amps@contesting.com
Search:                   http://www.contesting.com/km9p/search.htm


<Prev in Thread] Current Thread [Next in Thread>