[Amps] Follow-up...re: Time to ask for help.

[donroden at hiwaay.net]

Quoting Bill Turner <dezrat at outlook.com>:

> I agree with Vic's comments 100%.
>
> The only way to neutralize with a pi-input circuit that I know of is
> with a coupling coil from plate tank to input tank, which I would NOT
> do. Too finicky to adjust and highly dependent on the tuning and
> loading of both circuits.

Somewhere, I saw a neutralizing circuit that used a ten turn toroid  
between ground and a small pf value capacitor to the output network.

Another ten turns ( 180 degrees out of phase ) on the toroid went  
between ground and the input circuit through a small pf capacitor.

Amplitude was controlled with a capacitor from ground to one of the  
legs of the toroid.  I imagine a variable resistor across either side  
of the toroid would do the same thing on a single band amp for six  
meters.

But !!  If he is using Eimac SK-630 or similar tube sockets with built in
low inductance screen capacitors, there shouldn't be a need for any form
of neutralizing.

Don W4DNR