[AMPS] Re: New G2DAF amplifier information

[measures]

>
>Rich says:
>
>>Can you accept what is on the constant-current curves? 

>Yes - but what has that got to do with it?

When the curve deviates, the resultant signal feculates.  
>
>Quote again from Pappenfus et al. 'Most power tubes have a more linear plate
>characteristic operating Class AB2, however.'
>
My guess is that he is not all that familar with constant current curves. 
 Eimac rates two tetrodes for Class AB2 grid driven linear service.  

>	>I do not agree.  Modern transceivers need a 50-j0 ohm load.  With
>grid 	>current, the load Z on the exciter goes bananas
>
>
>Not necessarily so. It depend on the relative ratio of grid swamping to non
>linear grid current loading. 

Tossing off the effect of rapidly decreasing grid resistance as grid 
current flows does not wash. .    

>   Additionally, you appear to assume that the
>input impedance of grounded cathode AB1 stage is constant and high.  

[chortle] 

>This is
>not necessarily so - because of Miller effect.
>
>If the driver has adequte NFB to reduce its output impedance, the effects
>are minimised.
>
I know of no commercial radio that works well with other than a 50-ohm 
load.

cheers, Peter

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


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