[Amps] config cathode-drive Amp with a Tetrode?

[Mike McCarthy, W1NR]

Hi Joe,
   It depends somewhat on what tube you use.  The 4-1000 has grids with
sufficient rating
so that you can strap them to ground and run it like a grounded grid triode.
Most tetrodes
don't.  The 4CX1000 has been used in a number of different configurations,
but always
with screen and grid bias voltages applied.  The Collins 30S-1 strapped the
screen to the
chassis ground and applied the screen voltages (and the drive) to the
cathode.   You don't need
to worry about 100W drive, but you do need a tuned input.  You can also run
it in
conventional grounded cathode with grid drive.  This usually requires
swamping resistors
to dissipate most of the drive power and create a voltage waveform to drive
the tube.  In
this configuration, a tuned input is generally not needed.

73 de Mike, W1NR


----- Original Message -----
From: "G & M Johansson" <gurantem@ettnet.se>
To: <amps@contesting.com>
Sent: Friday, March 15, 2002 11:45 AM
Subject: [Amps] config cathode-drive Amp with a Tetrode?


> How should a proper schematic configuration of a cathode-driven Amp
> be done with a Tetrode ?
>
> I've seen a couple of variations:
>
> 1) Both grid, Screen grounded
> (guess its a common way of solving it....
>  Also described in the book:
> Power Vacuum Tubes Handbook, 2nd ed)
>
> 2) Grid to ground , Screen to DC-screen -voltage
> (a few russian schematics)
>
> 3) Grid to Cathode, Screen grounded
> (from AG6K's excellent site)
>
> Which one is the 'proper' way to do it?
>
> Does it depend on what kind of tube being used?
>
> SM0EJR /Joe
>
>
>
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