More publications on low voltage tube operation

Triodes at Low Voltages - Merlin Blencowe
http://www.valvewizard.co.uk/Triodes_at_low_voltages_Blencowe.pdf
In French too:
https://sourceforge.isae.fr/attachments/download/2262/Triodes_en_Faibles_Tensions.pdf
In Chinese?
http://hoyoung2.blogspot.com/2013/11/triode.html


Low voltage vacuum tube pre-amplifier for guitar - Eric Nolan Sporer - Master of science thesis - Chalmers University of Technology
http://publications.lib.chalmers.se/records/fulltext/159599.pdf


These publications use the term pull up resistor for what is called in euroelectron Pleiades bias resistor or anode to grid resistor.


Further reading:


The Pleiades bias - euroelectron






Operating Features of the Audion - E. H. Armstrong