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[AMPS] Re: Drive Level in amplifiers

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Subject: [AMPS] Re: Drive Level in amplifiers
From: (Rich Measures)
Date: Mon, 23 Mar 98 15:47:23 -0800
>One other point on drive level:
>If the point were true that input impedance varies with drive, then in 
>order to have an amplifier system that is operating properly, one must 
>always operate it at maximum drive.  
>If not operated then at maximum 
>drive, the matching network is not properly attenuating harmonics, not 
>providing the proper "flywheel" affect, etc.

- The flywheel makes things mo betta, and it's always there.  
>It is not always beneficial to run an amplifier at maximum drive.  

During ssb modulation, the drive varies widely during each spoken word.  
However, max. peak drive and max. anode-I is essential to correct tank 

>You might just want to run with 500 watts out instead of 1500.  Or you might 
>be running RTTY.  In both cases, you would need to back off on the drive.
>I know there is a difference between small signal and large signal 
>S-parameters in an active device.  The question is is 5 watts considered 
>a small or large signal condition?  Perhaps you are right in that the RX 
>noise bridge is too low a level if 5 watts in is considered large signal. 
> We shall see.  I don't really think there is that much difference 
>between small and large signal impedance variations, however.

When you hook a large signal Z-analyzer direct to cathode, you will know. 

Please consider that:  Below a certain drive level, zero grid current 
flows.  At max. drive, grid current flows.  
-  later, Jon


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

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