If you want a simpler set-up, I believe that the Pure Vinyl license allows you to also download and run Pure Music using the same activation code, so you could try that.
For Pure Vinyl, I'd check that all of the following are set to using the DAC and that they are set to a sampling rate that the DAC can handle.
1) Check if there is a configuration program for your DAC, could be a stand alone application or a preferences pane in System Preferences
2) System Preferences > Sound > Output
3) Applications > Utilities > Audio MIDI Setup
4) Pure Vinyl > Preferences > Multichannel > Setup (Make Sure Bus 1 is set up to output properly)
5) Pure Vinyl > Preferences > Advanced Audio Setup > Device Selection > (Set this up so either you select outside of PV or from the application - if set to within PV make sure that it is set to the DAC, may need to relaunch the program to take effect)
One other obvious thing is just to ensure that Mute or Dim aren't selected in the PV interface and the volume sliders aren't at zero. If the input is set to the internal Mic, PV will mute the output and set the volume to zero, to avoid feedback, so you may have to adjust it back to a level where you can hear something. You can defeat PV from taking this protective action in the preferences if it bugs you.
Jim C