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[Amps] ALPHA 77

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Subject: [Amps] ALPHA 77
From: (2)
Date: Sun, 4 Aug 2002 19:05:24 -0700
>-----Original Message-----
>From: []On
>Behalf Of 2
>Sent: 05 August 2002 00:17
>To: Phil Clements;; Bob; AMPS
>Subject: Re: [Amps] ALPHA 77
>>> Why would one need to tune for grid-current ?  Minimal grid current does
>>> not give a correct tune.  Maximal grid-current does not give a correct
>>> tune.  A correct tune is max out with the drive needed to produce 1A of
>>> anode current per 8877 -- which coincidentally results in c. 100mA
>>> grid-current per grid, which could be seen on a 0-500 scale.  However,
>>> there is no need to measure  grid-current on a cathode-driven amp.
>>> Grid-driven, yes.
>>When I tune an 8877 amp, I tune everything for maximum power out.
>>I then tweak the PA loading cap slightly to give a needle-width decrease
>>on the wattmeter. I need to see the grid current at this time to make sure
>>it goes down and not up when making this adjustment. This slight reduction
>>in suds makes a nice increase in clean. 
>>>True, Phil, but the 8877 is so clean that there are no transceivers even 
>>>in the same league.  
>Ain't that the truth and ain't that a disgrace!
Good point, Conrad.   All it would take to make a solid-state final unit 
cleaner is some neg. feedback R in the emitter or source leads.  This 
would be easy to do with 50v transistors.

-  R. L. Measures, a.k.a. Rich..., 805.386.3734,AG6K,  

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