[Amps] Plate Cap Quandary

[Manfred Mornhinweg]

Hi Carl, Marv,

I was about to suggest to simply reverse the order of things, and do this:

1) add up the tube's capacitance, stray capacitance, and minimum 
capacitance of the plate tuning cap;

2) Calculate the PI network for that input capacitance, which will 
require a higher loaded Q than the one your original capacitance spec 
was based on;

3) Put up with the more critical tuning and higher losses caused by this.

But after reading Carl's suggestion,

> Simply wind the 10M coil as per the software program using your favorite Q 
> while ignoring any C. Then center tap that coil with the Tune C; it will be 
> 4X ratio so now you need 4X the C to resonate.
> 
> The effect carries thru  the other bands and rapidly becoming unoticable.

I cannot do anything else than bow my head to long-standing experience, 
and mention my own idea just for its anecdotical value! Do what Carl 
says, Marv...

I will go back to my MOSFETs instead. My experiments are advancing. I'm 
fighting device capacitances too, but in another way... I hope that in a 
few months I will be testing a low cost mosfet legal limit amp on the air.


Manfred.

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