I got it! It is finally working.
Issuing the following command in the terminal
sudo apt-get install pulseaudio alsa-utils
fixed the issue.
I tested the DAC by further issuing (which is why I also installed alsa-utils to get aplay)
cat /dev/urandom | aplay -D hw:1,0 -f S24_3LE -c 2
After installing the package a new sound card called “Pulseaudio” became visible in Settings->System->Audio which corresponds to the USB DAC.
Music (even airplay) and video playback works.
I used Configuring Sound on Linux/Pulse Audio/Troubleshooting - Wikibooks, open books for an open world for reference.
No asound,conf necessary :-).