What is cards.json file intended for ?

According to Volumio documentation, new DAC has to be defined in dacs.json file located at volumio/blob/master/app/plugins/system_controller/i2s_dacs/.
But, similar DAC definitions are stored in cards.json file located at volumio/app/plugins/audio_interface/alsa_controller/.
So, to define a new DAC, shall we fullfil both files ?
Thank you.

Hi, on i2s dac you need to add infos relevant only to i2s DACs, while the other stores the default mixer and the name of all other dacs (like internal, USB etc)

Hope this clears it!

Yes !
Thank you.