06-10-2016, 06:26 PM
(This post was last modified: 06-10-2016, 06:38 PM by Mike Watterson.)
It does really comply with valve theory, but of the advanced kind!
All the rod tubes are really electron guns with two beams in opposite directions from filament and g1, g2, g3 are really electrostatic lenses. The 1j29b and 1p24b are actually two sets in parallel, hence two filaments and a an extra shared plate/rod for g1, g2 and g3 between the two parallel beams!
Americans tried making rod electrode tubes in 1930s but it failed because the cathode was indirect. The Russian guru that invented these realised that unlike a CRT the idea would ONLY work with a very very thin perfect direct filament cathode with the g1 plates very very close on either side to form the pair of beams.
All the rod tubes have dual g1 plates (internally connected) and four or six g2 and g3 rods or plates internally connected. With the 1j37b they removed some shielding rods so that access to g1a and g1b are separate. The 1j42a is last model.
Most gain:
6V HT! (Equivalent to tetrode kink area of beam pentode)
g2 to direct to HT, g3 to f- or f+ (forget which)
tie g1a and g1b together. It's the opposite effect to an op-amp.
If you have differential RF in with a centre tap on transformer to g1a and g1b, then volts on centre tap adjusts threshold / gain and the RF is rectified (or frequency doubled) depending on if AF load (resistor or audio transformer and capacitor to OV) (or if RF tuned / RFC).
Have fun.
I'd only use one of these as mixer/osc ,RF AGC, frequency doubler, unusual detector etc, maybe IF. The 1j24b will work with 2 x 12V alkaline A23 or similar and takes similar heater current.
It will be interesting to try it at 88 to 108MHz and 110MHz to 137MHz as a mixer/osc on a superhet or super-regenerative. They could be used also as IF dual 470KHz & 10.7MHz with AGC but not a regular IF amp. I have Russian schematic with older 1j37b as AGC stage. I'll look for it.
All the rod tubes will work as logic gates (Resistor Nor Gates) or amps using positive g2 with no need for capacitive coupling or level shifting, with suitable HT!
Wrecked moving junk out of new workshop.
All the rod tubes are really electron guns with two beams in opposite directions from filament and g1, g2, g3 are really electrostatic lenses. The 1j29b and 1p24b are actually two sets in parallel, hence two filaments and a an extra shared plate/rod for g1, g2 and g3 between the two parallel beams!
Americans tried making rod electrode tubes in 1930s but it failed because the cathode was indirect. The Russian guru that invented these realised that unlike a CRT the idea would ONLY work with a very very thin perfect direct filament cathode with the g1 plates very very close on either side to form the pair of beams.
All the rod tubes have dual g1 plates (internally connected) and four or six g2 and g3 rods or plates internally connected. With the 1j37b they removed some shielding rods so that access to g1a and g1b are separate. The 1j42a is last model.
Most gain:
6V HT! (Equivalent to tetrode kink area of beam pentode)
g2 to direct to HT, g3 to f- or f+ (forget which)
tie g1a and g1b together. It's the opposite effect to an op-amp.
If you have differential RF in with a centre tap on transformer to g1a and g1b, then volts on centre tap adjusts threshold / gain and the RF is rectified (or frequency doubled) depending on if AF load (resistor or audio transformer and capacitor to OV) (or if RF tuned / RFC).
Have fun.
I'd only use one of these as mixer/osc ,RF AGC, frequency doubler, unusual detector etc, maybe IF. The 1j24b will work with 2 x 12V alkaline A23 or similar and takes similar heater current.
It will be interesting to try it at 88 to 108MHz and 110MHz to 137MHz as a mixer/osc on a superhet or super-regenerative. They could be used also as IF dual 470KHz & 10.7MHz with AGC but not a regular IF amp. I have Russian schematic with older 1j37b as AGC stage. I'll look for it.
All the rod tubes will work as logic gates (Resistor Nor Gates) or amps using positive g2 with no need for capacitive coupling or level shifting, with suitable HT!
Wrecked moving junk out of new workshop.
