Amps
[Top] [All Lists]

[Amps] Schematics ??for 4CX250B GG HF amplifier

To: <amps@contesting.com>
Subject: [Amps] Schematics ??for 4CX250B GG HF amplifier
From: "Jim Thomson" <jim.thom@telus.net>
Date: Thu, 16 Aug 2012 03:22:07 -0700
List-post: <amps@contesting.com">mailto:amps@contesting.com>
Date: Wed, 15 Aug 2012 20:23:24 -0400
From: Bill Fuqua <wlfuqu00@uky.edu>
Subject: Re: [Amps] Schematics ??for 4CX250B GG HF amplifier

Every once in a while we revisit this topic.
I will just cut and paste the following from some time ago.

Bill Orr's article about super cathode driven tube amps
in the July 67 QST.
He has a example of a 4CX300A (control grid connected to cathode) cathode
driven amplifier.
It only has a power gain of 5. 375 watts out with 75 watts input. But the
nice thing is that the 3rd order products
were 46db down and 5th were -49. This is quite an improvement over most
amplifiers.
I have always wanted to do this using two stages one produce around
300watts output and the second 1500 watts.
A 4CX250b driving 4 parallel 4CX250B tubes. Should get similar results. This
naturally would require 50 to 70 watts drive.

73
Bill wa4lav

##  several  4CX-1000 amps in  super cathode  config were built locally  back 
in the
70’s  and also  80’s..with great success.    Control grid strapped to cathode, 
and 
screen grid  bonded to chassis.  The entire mess was operated as a high mu 
triode. 
160 watts of drive  for 1200 w out.    8.75 db gain.  No resistor’s  used 
anywhere.  
The 4CX-1500 can also be used in the same config.   PI type  tuned input 
required.

##  The 4CX-5000  has plenty of control grid diss.   The 4x5  and 4x10 in GG
was just like any 4-1000 in GG.   Both grid + screen strapped to chassis. 
Then you drive it with a SB-220  in the CW position.   The 4x15 has even more 
control
gris diss.   Same deal.     PI type tuned input required. 

Later.... Jim   VE7RF

_______________________________________________
Amps mailing list
Amps@contesting.com
http://lists.contesting.com/mailman/listinfo/amps
<Prev in Thread] Current Thread [Next in Thread>
  • [Amps] Schematics ??for 4CX250B GG HF amplifier, Jim Thomson <=