----- Original Message -----
From: "Vic Rosenthal" <vic@rakefet.com>
To: <wlfuqu00@uky.edu>
Cc: <amps@contesting.com>; <philk5pc@tyler.net>
Sent: Saturday, October 09, 2004 8:10 PM
Subject: Re: [Amps] Need for input tuning circuit
> Years ago I built some 813 amplifiers for CW work. I used the
standard
> clamp-tube circuit in which class-C bias is generated by the grid
current flow
> through a resistor (i.e., the bias is in effect rectified driving
voltage) and
> the clamp tube protects the tube by removing screen voltage when the
key is up.
> This had the advantage of preserving the keying waveshape while
running the
> tubes in full class-C for efficiency.
Hi Vic,
How was full class-C maintained on the opposite cycle, when no grid
current flows?
For full class-C the 813 has to be biased with -155V at 2250V EHT
73
Peter
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