20-10-2023, 02:37 PM
(This post was last modified: 20-10-2023, 02:42 PM by Mike Watterson.)
Ukraine and Bulgaria. The Ukraine suppliers were offline or unable to ship for a while.
The 1j24b (not 1j24p, it's a monster) is the most versatile to replace most 1.4V valves. Need a small ballast resistor on f- and may need a pull down resistor on g2. The 1j29b only needed when more than 400mW needed.
Any mixer can be implemented as plug in replacement using 2x 1j24b, one as a triode oscillator and that can direct drive g2 of the RF in/Mixer. Less LO leakage than DK91, DK96, DK92 and 1L6. You need to add extra capacitance to have tuning free plug-in replacements as the 1j24b (and rod "pentodes" in general) have very much lower capacitance. The 1j24b will replace a DF97 as triodised mixer/oscillator or as Pentode Mixer (Vidor VHF/MW/LW set) or 10.7 MHz IF. Will also replace DAF9x (add 1N60), DL91, DL92 & DL96. Really a DL94 at full wack needs a 1J29b, but a 1j24b can be used with some bias adjustment in some sets. A pair of 1j24b in push pull class B can certainly do HiFi at 1W.
https://www.radiomuseum.org/forum/russia...es.html#11
The 1j24b can typically be at about 11mA at 1.2V (small series resistor for Zinc, Alkaline or 1.4V supplies!). The 13mA is a worst case!
Maybe link to my graphs
https://www.radiomuseum.org/forum/russia...es.html#18
Dmitri Faguet also has done a lot.
The 1j24b (not 1j24p, it's a monster) is the most versatile to replace most 1.4V valves. Need a small ballast resistor on f- and may need a pull down resistor on g2. The 1j29b only needed when more than 400mW needed.
Any mixer can be implemented as plug in replacement using 2x 1j24b, one as a triode oscillator and that can direct drive g2 of the RF in/Mixer. Less LO leakage than DK91, DK96, DK92 and 1L6. You need to add extra capacitance to have tuning free plug-in replacements as the 1j24b (and rod "pentodes" in general) have very much lower capacitance. The 1j24b will replace a DF97 as triodised mixer/oscillator or as Pentode Mixer (Vidor VHF/MW/LW set) or 10.7 MHz IF. Will also replace DAF9x (add 1N60), DL91, DL92 & DL96. Really a DL94 at full wack needs a 1J29b, but a 1j24b can be used with some bias adjustment in some sets. A pair of 1j24b in push pull class B can certainly do HiFi at 1W.
https://www.radiomuseum.org/forum/russia...es.html#11
The 1j24b can typically be at about 11mA at 1.2V (small series resistor for Zinc, Alkaline or 1.4V supplies!). The 13mA is a worst case!
Maybe link to my graphs
https://www.radiomuseum.org/forum/russia...es.html#18
Dmitri Faguet also has done a lot.
