In response to a post about setting up the DAC card the poster was referred to the PI Troubleshooting documentation. I saw in there the note about disabling the native analog output, so thought I may as well do that. It instruct you to comment out the snd-bcm2835 line in the /etc/modules-load.d/raspberrypi.conf file.
My /etc/modules-load.d directory is empty and has no raspberrypi.conf.
Has this moved in newer builds?
Ian