The History of Low Anode Voltage Operation

It would be nice if such an article existed. See a later attempt:
http://euroelectron.blogspot.com/2018/07/history-of-low-plate-anode-voltage.html


Giving chronology of events, designs or publications.


For example beginning with space charge tetrodes?


Or beginning with Edwin Armstring observation that even an unconnected grid impedes the flow of electron.


The article could include connecting a battery with the plus polarity towards the grid in order to make a 12V headphone amplifier possible, a patent on guitar amplifies, Pleiades amplifiers, publications etc.


See also:


http://euroelectron.blogspot.com/2017/01/vacuum-tubes-at-low-plate-anode-voltage.html


US Patent 5022305

 http://euroelectron.blogspot.com/2015/10/pleiades-electra-13v-electron-tube-pre.html
(It is not positive grid, just less negative)