I'll be honest. There is no single magic bullet in my experience for listening fatigue. I have found all of these to matter for digital music
1. use PC source with asynch USB (check, you are doing that)
2. use a quality DAC (check, you are doing that)
3. use quality interconnects (check you are doing that)
4. use a quality PC media player (no, you are not doing that... consider JRiver or Foobar2000. At lower processor speeds Foobar is better but with the latest generation of CPU's JRiver is as good or better and much more user friendly. Itunes is pleasant but shallow in musical detail)
At this point your PC audio out shouldn't be the source of fatigue. Look to the rest of the system. Consider a Rogue Cronus or a Prima Luna integrated tube amp as a safe choice to bypass solid state issues that commonly cause listening fatigue. Leave speakers for last.. buying better speakers at this point will likely expose more to hate.
1. use PC source with asynch USB (check, you are doing that)
2. use a quality DAC (check, you are doing that)
3. use quality interconnects (check you are doing that)
4. use a quality PC media player (no, you are not doing that... consider JRiver or Foobar2000. At lower processor speeds Foobar is better but with the latest generation of CPU's JRiver is as good or better and much more user friendly. Itunes is pleasant but shallow in musical detail)
At this point your PC audio out shouldn't be the source of fatigue. Look to the rest of the system. Consider a Rogue Cronus or a Prima Luna integrated tube amp as a safe choice to bypass solid state issues that commonly cause listening fatigue. Leave speakers for last.. buying better speakers at this point will likely expose more to hate.