What brand and model i2s dac are you using...?
A similar question was answered here...
https://www.snakeoil-os.net/forums/Threa...85#pid2685
You will also have to add to /boot/config.txt....
dtparam=i2s=on
and for some dacs it will help to add..
dtparam=i2c_arm=on
add both to cover all bases.