124B Pentode Dual Tube Breakout Board. Not a fun Post.

 

Sad to say that AudioDiWHY has not been fun over the last few weeks. A pervasive sadness has crept in and my pychiastrist girlfriend says I need a break.

I finished working on the tube timbre trasher (part one here).....where I am designing and prototyping a synthesizer waveform distortion module using a Soviet-era low voltage pentode, the 1J24B. For this post, let's focus on the breakout board needed for the prototype. I'll post the rest in a few days.

Tube audio! Fun stuff right? The Soviets—they knew tubes!! Long gone and good riddance?  Let’s take some tiny, low voltage tubes used in USSR fighter jets, turn swords into plowshares, and use them for audio! 

Until….until....when cleaning out my lab, I mindlessly dug up the box the 1J24B's came in:

 

I redacted the Ukrainian vendor's name and address, but after searching the web, as far as I could tell, the Ukraine was the primary source of the worlds' NOS, affordable 1J24B's. 

Needless to say these parts, which were really easy to obtain 2 months ago, are no longer available on Ebay, and perhaps anywhere else, due to heartbreaking world events.  

Specifically, the 1J24B's I had been using for my prototypes came from the same Ukrainian city you see in the war correspondence here. 

The news from this part of the world is maddening, confusing, and at times, terrifying. My psychiatrist girlfriend, usually tough as nails, was about as scared and upset at the news of the conflict as I've ever seen. The battle at Zaporizhzhia made her frightened for her kid, who is studying abroad, not too far away from the conflict, as well as for herself, for the world, and for me. 

This made me want to stop working on this for-fun project and spend my time doing more useful and constructive things. But I am still stuck at home due to the global pandemic, and found myself continuing to work with my remaining 1J24B's.

 

Anyway....putting politics and emotions temporarily aside, well before I realized where I sourced the parts from, I created a two tube version of the 1J24B breakout board you see in previous posts here and here. I posted the files for this board on my faithful sponsor, PCBWAY's project page, here. 

The design requires you have some 1J24B’s already or can get some.

UPDATE: 5-25-23 Tragically: the war in Ukraine drags on, but these tubes are available again from Western retailers. Synthcube for instance has them in stock as of today it appears: go here.

If so, you can use this PCB to breadboard a low cost, low voltage dual tube design, say a push pull amplifier or a tube based op amp. 

Cathodes for this BOB require ground and -2 to -15VDC. See the post here for how the 1.5V direct cathode power works.

Under different circumstances, I’d be all over further experimentation; finding audio uses for these extremely interesting tubes would be a lot of fun.

 

Now, not so much. Due to the war, it's not much fun experimenting with these parts.  Maybe it's just me.

Damn.