A very interesting electron tube compression patent

It seems the anode is the screen grid. And the anode is used as an anode of a diode to crate to side chain DC signal for gain control or reduction?!


US2373180


https://worldwide.espacenet.com/publicationDetails/originalDocument?CC=US&NR=2373180A&KC=A&FT=D&ND=3&date=19450410&DB=EPODOC&locale=en_EP


http://euroelectron.blogspot.com/2018/08/interesting-automatic-gain-control.html


See also how it may be done automaticly by the diode rectification of the grid:


The Neumann U47 compressing - euroelectron


Operating Features of the Audion - E. H. Armstrong