Joe,
The link is below. No, at the valuse there, it don't make sense at all, or to
me I can't see it. I've never seen anything set up that way.
http://www.angelfire.com/nb/ni4l/gu84b.html
Best,
Will
*********** REPLY SEPARATOR ***********
On 1/30/06 at 8:37 PM John Popelish wrote:
>Will Matney wrote:
> > What I looked at in the schematic didn't make one lick of sense
> > to put a cathode choke to ground on a grid driven amp,
> > then place a shunt resistor across the choke
> > (especially that high of value).
> > The resistor wouldn't serve any purpose unless the choke opened.
> > And if it did, you'd really be better off not to have the resistor
> > so the tube would not conduct at all.
> > Also, the choke isn't needed as there's NO RF there to block
> > from ground. He also put a RF choke across the attenuator resistor
> > going to the control grid.
> > That don't make sense to me. I would think you would use two
> > non-inductive resistors. (Rich will jump me for calling them
>that). > He also has a choke in series with one of the attenuators
>resistors
> > going to ground which would raise the impedance there too.
> >
> > All I've ever seen here, for an attenuator, is a couple of
> > non-inductive resistors.
> >
> > Why put a choke in series with the screen lead? All that's needed
> > is a bypass cap at the tube socket pin. Here, the cap is on the
> > other side of the choke where it's shouldn't be.
> > Last, there's a 0.001 bypass cap hooked right from the control grid
> > to ground on the wrong side of the RF blocking choke.
> > The RF will go to ground and not to the tube!
> >
> > Am I missing something about this?
>
>Is it possible that these chokes and capacitors you mention are pars
>in a peaking circuit, to push the frequency response of the amplifier?
>That would explain the high value parallel resistor (limiting the Q)
>and the cap on the tube side of the grid choke (to form part of a
>resonance, not a bypass). I am afraid I have lost the original link
>to the schematic, so I can't easily look if this explanation is
>reasonable or silly.
>_______________________________________________
>Amps mailing list
>Amps@contesting.com
>http://lists.contesting.com/mailman/listinfo/amps
_______________________________________________
Amps mailing list
Amps@contesting.com
http://lists.contesting.com/mailman/listinfo/amps
|