[Amps] Grid Vs cathode drive

[Tom W8JI]

> The downside is that you need tuned circuits in the 
> cathode for decent linearity - I was always surprised at 
> the 30L1 not having those.

Do you mean the S1?

> The grounded cathode tetrode with grid swamping isn't to 
> be discounted, but  can have the linearity improved with 
> negative feedback, without too much difficulty.
> Does this answer the question?

If you look at actual tests of IM all these "clean" grid 
driven 4CX800 tetrodes are nowhere as good as a cathode 
driven 3CX800 or similar.

When you look at the regulation and protection required for 
screen and control grid bias systems there isn't a penny 
saved. The only thing cheaper is the tube, and that is true 
only while you can still buy them from "surplus" 
distribution.

73 Tom