The synth was to be designed around the STM32F103C6T8 "Blue Pill" board because they are less than $2 from AliExpress, theoretically supported with the Arduino environment, and better than the available AVR dev boards in every way. 72MHz vs 16Mhz. 64-128k of Flash (program) memory vs the Arduino's 32k. 20k of RAM vs 2k on the Uno/Mini/Micro. And having a 32 bit ARM processor with better math seems like a great idea as well!

But after talking with the guys from MAGfest when I was starting to get back to work, they convinced me to look at the ESP chips. I don't need the WiFi, and they seemed to start at $7  so I didn't really see how they were applicable to my project. But they convinced me that they were actually cheaper now, and hugely faster and posessing of tons more memory. The new ESP32 is even a dual core part!

They also told me about these great D/A audio converters called PT8211 that does stereo and can be used over SPI... furthermore, they cost $0.02, so completely within my budget!

So I ordered a bunch of parts! But AliExpress is a minimum of two weeks...

But I'm not gonna sit on my hands in the mean time, so I guess I'll keep working with the STM32...

When the parts finally did get here, I was kinda already too far along in the design with STM32, so the parts have kinda been sitting on my desk. Maybe for version 2...