[Amps] Need for input tuning circuit

[DF3KV]

----- Original Message -----
From: "Vic Rosenthal" <vic at rakefet.com>
To: <wlfuqu00 at uky.edu>
Cc: <amps at contesting.com>; <philk5pc at 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