Band: opinion spread · Dot: weighted average
Sources split: on the question that always splits DAC reviews — whether the box has a sound of its own. The bench says it shouldn't: L7Audiolab measured roughly 122–125 dB SINAD depending on output and level, the territory where distortion and noise sit far below audibility. The listeners who tested that directly agree. Z Reviews level-matched the SU-9 Pro against the $900 SU-10 through a Topping LA90 and found any difference too small to be worth the money; an ASR owner who had both the SU-9 Pro and the D400ES heard no particular difference even sighted; another owner who cycled through the D400ES, SU-9 Pro and DO300 found all three sounded the same. The other camp — the larger one by weight, and mostly long-session reviewers — describes a distinct character: Headfonics hears a smooth, composed timbre and calls it far from the brittle sound of poorly executed ESS DACs, iiWi a weighty, lively Sabre presentation, Tharbamar a vivid, spacious one, and a Head-Fi owner near-microscopic detail and the smoothest bass they had heard. A minority hear it and are unmoved: an owner who tried it against Topping's E70 Velvet liked the Topping more.
Measured
L7Audiolab (Audio Precision, Oct 2022): SINAD 123.9 dB from XLR at 4.17 Vrms, 125.3 dB at the 5.25 Vrms setting, 122.3 dB from RCA at 2.13 Vrms; dynamic range 130.4 dB unweighted, 132.7 dB A-weighted. SMSL rates THD+N at 0.00005% (−125 dB). An ASR member noted the bench SINAD sits a few dB under the 127 dB SMSL quoted at launch.
vs. listeners — The bench leaves no distortion or noise large enough to explain a 'character', so the split most likely tracks method rather than units: the two listeners who matched levels or swapped boxes directly heard nothing, while none of the character reports describe level-matching — and the XLR outputs run about 6 dB hotter than the RCA. The Sound Color presets do deliberately alter the sound; reviewers who heard 'character' don't all say whether they were off.
“Sweat rolled down my forehead in tension, but I never heard any particular difference between them.”
neg, comparing his SU-9 Pro with SMSL's D400ES — Audio Science Review
“Charming like a gracious gentleman yet strict where it counts, that’s how the SU-9 Pro seemed to me.”
Aldous, Headfonics