[Amps] Designing the Cleanest Linear with RF Negative Feedback

[Steve Thompson]

wc6w at juno.com wrote:

> P.S. -- Steve T. posited in another post that there was little intrinsic difference between a vanilla 4CX350A and the 4CX350FJ.  The data sheet claims 10dB lower distortion at equal power.  That's a lot.  I wonder if Eimac uses a striped cathode aligned grid scheme, as in the 4CX600J & 4CX1500B, in the '350FJ?   
In the data I have, only the FJ has IMD data in the specs - but it's at 
either 100 or 250W out, even if that's average power it's less than the 
tube is capable of. It reminds me a lot of the ratings I'm used to with 
semiconductors where generic parts are respecified at lower power in 
order to get linearity for specific applications. I stress it's just my 
guess, and I'm wide open to correction.

Steve