Direct-coupled cathode/source follower driver in PP?

[Bandersnatch]

Originally posted by kevinkr


Hey Doug,
Highly dependent on tap position.. Cmiller obviously should be less at 25% taping (near pentode) than at 43% or 50%.. On cursory inspection your equation looks ok.. Haven't thought about it much as I no longer do pentode or UL amplifier designs.

Kevin,
With pentodes, it is g1 to g2 capacitance that matters. Hold g2 'still' and g1 sees very little capacitance. Clearly when g2 has signal it will have multiplied the C just as in the triode/miller effect. Higher tap %-age and there is more effective capacitance seen by g1.
cheers,
Douglas

[kenpeter]

Originally posted by oldeurope
Do you agree with the following text:

output uebertrager => UL and neutralisation is possible.
output transformer => UL and neutralisation impossible.

ok?

Darius

Neutralize plates to opposing UL screens.
Neutralize UL screens to opposing grids.
Would it work?

[kenpeter]

Assume beam power, where the supressor grid is virtual.

[smoking-amp]

Hi Ken,
Probably working OK, but I don't see any point in the neutralizing to the screen grids. The plate still has to drive the same capacitance either way, either the UL tap point does it or the Neut. cap. from plate does the driving. From the UL tap it even gets some trashformer ratio to help out.

Don