This might be OT, but there was some interest expressed in more posts about synthesizers…
These circuits are based on classic designs by Dave Rossum that were used in a lot of classic synthesizers. With a few of these inexpensive ICs you could build a DIY analog monosynth on a breadboard. Plug in a keyboard with control-voltage output, like an Arturia KeyStep, and you’re ready to rock. If I had the analog-electronics chops to know what I were doing, I’d totally do it.
Do it. Analog is pretty forgiving, and if you stay away from vacuum tube voltages, you can’t hurt yourself. Even if you get it a but wrong, you get a sound, which is fun.
Am I missing something or this is just blatant (self) promotion of a brand?
Yeah, I guess you’re missing something. I have nothing to do with this company — I mentioned I don’t even know what I’m doing with analog electronics — so how can it be self-promotion?
As for promotion … this is something cool I recently discovered that might appeal to some people here. Yes, these are hardware components, so they cost money. So do Raspberry Pis, Sublime Text, and various other things that get posted about here. I don’t think we have any rule here stating that only free products can be posted about.