[Amps] grounding grids

[Fuqua, Bill L]

If I recall correctly there was an article in QST in the 60's of an amplifier using a pair of  4x150A tubes with both grids grounded but the output power was limited by the drive. About 2 issues later Bill Orr published one with a pair of 4x150A or 4CX250 tubes with the control grid connected to the cathode. He explained that if you connected the control grid to ground with the screen grid you would fry the control grid before you got full output. 
   I believe somewhere there were some articles on Super Cathode drive where the screen grid was connected  directly to ground but the control grid was on a tap near the cathode on the cathode choke. This allowed some drive to the control grid to increase the gain of the amplifier. 

73
Bill wa4lav

________________________________________
From: amps-bounces at contesting.com [amps-bounces at contesting.com] On Behalf Of donroden at hiwaay.net [donroden at hiwaay.net]
Sent: Sunday, August 02, 2009 10:47 PM
To: amps at contesting.com
Subject: Re: [Amps] grounding grids

But did anyone come up with the original article of using 4CX-250Bs in
"semi" grounded grid ?  I believe my amp used 100 ohm 2 watt on each
grid to ground with the screens direct to ground.

Don WA4NPL

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