I'm not sure where the distortion would be coming from. If you're using DLNA to your DAC, are you using the "Audiophile 24-bit DAC" DLNA preset in the "Media Network" options?
If you're using USB to your DAC, in Audio / Output mode settings... are you using "Hardware default" for the buffer size? Using the Maximum setting here can cause problems with some DAC's. Also check which if any DSP options are enabled.