I like Ciat-Lonbarde and their Tocante instruments, but I also like to DIY stuff instead of buying it, so here's some info on making tocantes and similar things. If you want a good first-party resource on Tocantes, check out Peter Blasser's thesis
To improve the tone of the output I low pass with a .1uF cap to ground, and a high pass using a 1uF cap and a 2.2k resistor. This severely reduces the output, making it around similar levels to a guitar. If you made an output circuit, you could get a high-quality, powerful output, but I didn't want that. There's also a 5k power starve pot. I'll have gerbers up for something updated eventually.
Here's the tuning I made. Personally, I'd recommend going lower than that, as the lower tones sound better.
Here's the paper circuit.
I think I just did a .1uF to ground on the output to make it less shrill; again will need a preamp otherwise it will be guitar pickup level. Here's the stripboard layout.
I've also got a module that uses the thyristor oscillator, it has a narrow frequency range with CV but it's still pretty fun to mess with. Here's the paper circuit for that.
I'll do the bistab eventually, I just get a bit tired of rectangular waves.