Yes, the Audio Adapter revision D is compatible with both Teensy 4.0 and 4.1. Note, you will get better results if you use the micro-SD card reader on the Teensy 4.1, rather than using the reader on the audio adapter.
Likewise, if you solder a flash memory chip to the bottom of the Teensy 4.1, access should be much faster. However, the way the flash memory is accessed is different, and that is undergoing change in Teensydunio 1.54.
Hi again,
I am confused with where to place header pins on the Teensy Audio Adapter Board 4.0 (I will be using it with the Teensy 4.1)
Thanks for your help,
soky157