Your Benchmark DAC is hardly larger than the a typical remote. What this means is that it relies on op-amps rather than a robust conventional output stage. Not to once again declare that the emperor has no clothes but every time I see a Benchmark DAC in a major magazine get rave measurements assessments I cringe-the measurements of digital components including DAC's completely fail to address the sonic differences between components with robust analogue output stages and those that do not. There is more to it than that-the input stages, circuit design, isolation and grounding but the largest contributor to a great sounding DAC is the all-important output stage.
Let me give you an easy example-old fashioned cd players. Those that sound best but don't necessarily measure best are often designed by conventional amp builders-the likes of Bryston and years ago, Classe. The reason is that with their amp building background they pay attention and devote resources to the output stage.