This is an Audio preamplifier featuring a NE5532 voltage stage, Class A output stage and features like Input/Output selection, headphones output and soft start.
Haven't completed the in-depth Readme going through the design...
In the firmware directory(main.c) you can find the full cubeIDE project where I implement all the microcontroller functionality like softstart delay, the input/output switching and the user's last configuration save/loadup at startup from the MCU flash.