https://oernst.org/hamradio/tubes/1v1-el84/1v1_EL84_anglais.html
Have a look at the first schematic. I would be glad to have your opinions on it.
The author seems to separate the 'Q multiplication' from 'mixing-detection' functions but as far as I see I'm not fully convinced.
A similar (if not the same) approach can be found here:
https://circuitsaladdotcom.files.wordpress.com/2012/09/regen.gif
Arguing from the video later attached ... it seems definitely an excellent performer.
What do you think?