Alun, if you are willing to experiment, try different digital cables on DAC3. I don't know how DAC3 reacts to digital cables, but when I had my DAC2, it sounded amazing with Virtual Dynamics NiteII and later (a much bigger leap forward) with Virtual Dynamics Master coax cables. I know they are crazy expensive, but when I linked the dac and transport with these, I couldn't go back. And as I remember, DAC2 sounded great with Audience powerChord on it. Stock cord doesn't cut it there. A nice aftermarket power cord will make the dac sound smoother.
I heard DAC3 several times but not next to DAC2, so not sure of improvements.
I heard DAC3 several times but not next to DAC2, so not sure of improvements.