Vic Rosenthal wrote:
>> But why?
>> If you're running Class C, with proper grid bias in the absence of drive,
>> the plate&
>> screen currents will be essentially zero.
>> The ol' clamp tube scheme was used with "Linear" amplifiers.
It was also used in transmitters, such as my Heath DX-100. I became
familiar with the clamp
circuit (a 6AQ5) when I built a T-R switch on the Pi network and the electron
noise from idling
current was obvious in the receiver.
> If I bias the tube for class C, then the keying envelope will get very sharp.
> It would be
> a click generator.
Generating key clicks depends on a bunch of things, the use of a clamp tube
minimizes the amount
of negative bias that is needed to cut off the tube when it is not in use in
tetrodes and higher.
> What I'm thinking about now is having just enough fixed bias to barely cut
> the tube off
> (about 75V, I think) and have the rest come from the drop across a resistor
> in the grid
> circuit. Then maybe the bias will rise along with the drive more smoothly.
--
Ron KA4INM - The next election, I know what is going to happen, I'm going
to help.
_______________________________________________
Amps mailing list
Amps@contesting.com
http://lists.contesting.com/mailman/listinfo/amps
|