Russian rod pentode circuits

[Mike Watterson]

You can browse and see what's there or do a google search on the site for specific tubes.
I have some data posted here.
http://radio.radiotrician.org/2016/12/ru...-data.html
73

The original PDF is freely downloadable on www.radiomuseum.org
see
www.radiomuseum.org/forum/russian_subminiature_tubes.html
Link near the bottom

also
http://www.radicalvalves.com/russian/rus...entodes-1/
(I must update with 1j42a)
The 1j42a is low filament current and low HT dual grid (6V to 9V) (tied is INDENTICAL to regular type. The 1j37b is a higher power, high filament current dual grid for 60V to 90V). Much more gain.
The common mode signal is amplified most and the differential signal is less amplified, or within limits, not at all! Because the two grids are the two plates in every rod tube either side of the filament.  Thus a differential signal steers the beams away from the anodes instead of reducing or increasing the beams to anodes. Thus when suitable bias is chosen, a differential RF signal is frequency doubled (high pass on anode) or AM detected/rectified (low pass on anode). Thus it can be used as a mixer with regular signal as common mode, but bias is important. As a mixer, you'd feed g1a and g1b from oscillator transformer secondary and the audio (for modulator) or RF (for superhet mixer ) or IF (BFO) to the centre tap of the transformer.
The higher level LO acts like the chopper action of the beam switching tube used as mixer, I think the 7660. I suspect an output on g2 is thus possible as the g2 current is at a maximum at maximum differential signal on g1a / g1b and minimum Anode current.