[Amps] IMD levels

[craig]

I would be more concerned with the transceivers IMD level than the tube. The
new generation  of radios seem to be spiraling down at an alarming rate.
Figures of -24 db  below 1 of  2 tones is pretty lousy.

Most Tetrodes  are hovering around -36 db  down on the third order products.
You have exceptional linear tubes like the 4c1500B, and the 4cx600J which
have figures in the -40 db range. In the Larger bottles the mighty 4cx10000J
seems to have a good figure. Although i cant see the point of this tube when
simply lowering the screen potential of the standard 4cx10000 produces
similar 3rd order IMD figures with roughly the same output. I have never
been able to  read an explanation  to  what in the tube gives it good IMD
performance, maybe someone can offer an explanation.

Craig
VK3HE