By and large I don't believe there are many meaningful sonic differences between well designed electronics, whatever the subjectivists on this forum want to believe. If there are differences, they are not necessarily for the better (e.g tube sound). The straight wire with gain criterion was met ages ago with solid state amplification, and I am increasingly inclined to believe that the same is now true for DACs.
If it were only true, you could get the best DAC on the market for $500. Reviewers would not be giving rave reviews to ladder DACs that cost $10K+ and then buy them for themselves.
The thing that motivates people to believe that most DACs sound the same is that the sources that are feeding them have so much jitter. Take the transport for instance:
http://www.audiocircle.com/index.php?topic=154408.0
or a Sonos Connect:
http://www.audiocircle.com/index.php?topic=154310.0
And then add a S/PDIF coax cable:
http://www.audiocircle.com/index.php?topic=154425.0
If these sources are not reclocked, there will be enough jitter to mask most differences between DACs.
Add in an inexpensive active preamp, and you have additional distortion, compression and noise that will mask the rest.
The good news is that a good reclocker like the Synchro-Mesh can fix this. Also, replacing your active preamp with a good transformer passive linestage like this one will eliminate the active preamp contribution:
Every DAC has a different sonic signature. I have been to enough trade shows over 15 years to know this for a fact. And perfect measurements means little. The current measurement suite doesn't quantify dynamic response or jitter properly. New measurement techniques are needed for both of these metrics. This is why I'm doing the measurements above, direct jitter measurements.
Steve N.
Empirical Audio