The Airport Express has both analog and digital optical out.
If your DAC takes standard RCA type inputs, you can connect to the Airport Express via an RCA to 3.5 mm mini phone plug adapter.
Available from Ram Electronics:
http://www.ramelectronics.net/html/adapters.html
Or from the Apple store:
http://www.apple.com/
If your DAC takes standard RCA type inputs, you can connect to the Airport Express via an RCA to 3.5 mm mini phone plug adapter.
Available from Ram Electronics:
http://www.ramelectronics.net/html/adapters.html
Or from the Apple store:
http://www.apple.com/