Here's a brief comparison of two venerable dacs, the NAD M51 vs. the Benchmark DAC2 L... hope it's useful, and welcome comments and feedback.
System under test: Sonos Connect via coax (playing 16-bit lossless files) -> <DAC> -> Rogue Audio M-180 monoblock amplifiers -> ProAc Response 2.5 floorstanding speakers, in a medium sized (15’ x 25’) room.
Music preferences: jazz, rock; examples: Joshua Redman, Van Halen, Bela Fleck, Tool, Led Zeppelin, Wayne Shorter, Chick Corea, Jeff Beck.
Sonic preferences: accurate timbre; instrumental detail and articulation; soundstage; anything that feels a bit like listening to live music.
Purpose for the review: to evaluate an alternative to the NAD M51
Having lived with the NAD for some time, the Benchmark first struck me as crisper, more energetic, and more revealing through the top end. Its upper-frequency detail was exciting on some recordings, more forward and dynamic. Bass was tighter and faster compared to the NAD. As a guitarist, I noticed that electric guitars sounded a bit more like what I expect from a guitar amp: more presence and bite, while the NAD sound was subtly more distant/laid back; almost the difference between listening to the guitar cab speaker on or slightly off-axis.
The NAD on the other hand presented a more open and detailed midrange, almost bloomy, with a more relaxed frequency balance easier to slide into for long sessions across a variety of recordings. The DAC2 seemed not to blame per se, being as reasonably smooth and resolved through the upper treble as one could expect; it just seemed to expose a little too much high frequency energy from rock examples like early Van Halen, Tool, and the Police.
Perhaps more important than tonal leanings, were differences in soundstage. Using each dac direct-to-amp, the Benchmark was a little flat while the NAD had a deeper, more holographic stage. Some degree of flatness seems typical with dacs-as-preamps, but at least when paired with the tubed M180s (I had less luck with an ARC solid state amp) the NAD’s preamp was able to shrug this tendency off and deliver a satisfying soundstage.
The upshot is, I preferred the M51 in this system. It isn’t perfect: a bit too polite at times, ever so slightly wanting for tighter bass, more dynamics and transient energy, but still a fairly remarkable window into music, reliably musical, immersive and engaging. I can imagine the Benchmark on the other hand, livening up an overly warm system (or otherwise overly warm music); experimenting with pairing it with a separate preamp is probably worthwhile.