Re: [Amps] Negative feedback passive input tetrode

[Glen Zook via Amps <amps@contesting.com>]

The later 30S-1 amplifiers used the 4CX1500 tubes and a number of the earlier 
units have been updated to the 4CX1500 tubes.
The 3, or 4, depending on who you asked, 30S-3 amplifiers used the 
4CX1500. Glen, K9STH 
Website: http://k9sth.net

      From: "Fuqua, Bill L" <wlfuqu00@uky.edu>
 To: RCM <robrk@nidhog.net> 
Cc: AMPS submit <amps@contesting.com>
 Sent: Thursday, December 14, 2017 2:34 PM
 Subject: Re: [Amps] Negative feedback passive input tetrode
   
  The 30S1 is biased cathode driven 4cx1000a.  The negative feedback is to the 
control grid and is a voltage divider between plate and control grid. The 30L1 
was neutralized so that it would work properly on 10 meters.

It used an air core transformer and variable capacitor between input an and 
plate. Have to look at the schematic, but the parallel 811A tubes did not work 
well at higher frequencies.

  Being that I a looking at grid driven it is a bit of a different story. 
Neutralization of a grid driven amplifier prevents tuned-grid tuned-plate 
oscillation.

    Yes, the cathode resistor is the easiest method indeed.



   
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