1j29b (1j29b)

See also

1j29-v (1Ж29Б-В) and 1j29-r (1Ж29Б-Р)

This 1j29b (also listed as 1sh29b, 1ZH29B and properly 1Ж29Б) is still available as New Old Stock. But the 1j29-v (1Ж29Б-В) and 1j29-r (1Ж29Б-Р) are usually the same price.

More information generally in Russian Subminiature Tubes article

To thank the Author because you find the post helpful or well done.

Simply soldering a 1j29b on a B7G plug appears to work fine in an Invicta 29 radio instead of using a DL96 for audio output. Total HT current for the radio dropped from 6.7mA to 5.4mA @ 78V HT from battery. On mains with 104V supply the radio set also sounded fine.  In an "economy mode" enforced by disconnection of one of the two 1j29b filaments from the B7G plug, The LT current was total of 98mA  instead of  126mA (from 2 x Alkaline D cells in parallel). There wasn't any noticeable difference to audio quality or maximum loudness.

To thank the Author because you find the post helpful or well done.

This does NOT apply to the 1j29b-r which is completely different pin layout.

Blue wire is optional (pin 1 of DL96), unless filaments are in Series.

Angle 1j29b tube so wire 2 &  3 are either side of  pin 6 of B7G plug adaptor and wire 1 and 6 of tube are either side of  pin 3 of B7G adaptor. Use 4mm to 6mm sleeve on 1j29b wires. Cut  wires except g1 and g2 about 8mm. Only cut and solder  g1 and g2 wires after the others are soldered.

Don't bend top wire too close to glass (> 3mm) and use two sleeves, a close one over anode wire overlapping extension wire to Pin2 of B7G plug and a larger sleeve with a notch that fits over top tube glass nipple.

[Edit: Just to clarify, the 1j29b with just one half of the centre tapped filament (about 27mA @ 1.35V) appears to be able to deliver as much Audio power as the DL96 with both filaments connected (50mA @ 1.4V).  Likely it can be used instead of DL91, DL92, DL962 and equivalents]

To thank the Author because you find the post helpful or well done.