putting the components for the audio filter in, only for one channel though - since there will be a follow-up revision to address the other bugs found so far. still this tells us if audio this way works or not

and it does! :-D

somewhat audible sound came out of this mini speaker (just salvaged it out of a broken tablet to see if it works, don't intend to keep it hooked up) - the target in-ear headphones worked even better :-)

the software side followed this adafruit tutorial:

https://learn.adafruit.com/adding-basic-audio-ouput-to-raspberry-pi-zero/pi-zero-pwm-audio

the next steps on the audio topic would be to read-up on the device-tree configuration to properly setup the two pwm channels instead of the on-the-fly configuration