I bought this module a few years back. It’s a great digital oscillator with a few trick up it sleeve. It has a Teensy on the back loaded with the firmware. I bought it when it was still made with thruhole parts nowaday it comes as a SMD version. I should still be possible to build by hand. If your looking for a new osccillator be sure to check this one out and not be fooled by being on the market for some time now.
https://youtu.be/Y6nYw4C0TTg (not my video)
http://neutron-sound.com/noa.html
Difficulty to build: Hard /Medium
Newer version are all SMD parts.