Jack Schmidling wrote:
I need some help and can not find the answer anywhere.

When neutralizing a triode, how much leakage between grid circuit and
tank circuit is allowed?

I am looking at the output of the final loading cap with a scope and
get a few volts of RF when the NC is nulled. This is with 20 ma grid
drive or about 10W input. The output just tickles the wattmeter on
the 30 watt range and rises to about 10w when the NC in moved from the
null position.

Second question: should I see any leakage when the filament is off?

Thanks for your help.

Jack
The neutralizing capacitor compensates for the grid - plate capacitance
and possibly other
feed back paths. The maximum balance required depends on the gain of the
amplifier stage.

The balance has to be sufficient to keep the amplifier from oscillating
and a little bit more.
Assuming a gain of 10 dB, then the output with drive and the filament
off should
be more than 10dB below the drive level.

Usually a grounded grid stage doesn't require neutralizing because the
grid is grounded interrupting
the input to output capacitance

Cheers
Bill K7NOM