One of the SA-31’s greatest strengths is its ability to reproduce continuously shaded tonalities at the edges of notes—shadings that give notes their shape and substance. Perhaps as a result, this preamp presents images that have a consistently pleasing, sculptural solidity—never the flat, “color-by-numbers” quality that some solid-state preamps exhibit.
The only quality I found odd in the SA-31 was a textural discontinuity that sometimes came into play on intensely modulated upper-midrange passages. On the loudest of vocal swells—Eva Cassidy belting out “Stormy Monday” on Live From Blues Alley [Blix Street], for instance—the SA-31 momentarily exhibited a slightly hard, strained quality. This phenomenon doesn’t occur often, but it is noticeable when it does because it is out of character with the preamp’s ordinarily smooth, imperturbable sound.
The SA-31’s bass was hearty and solidly weighted, although I found the preamp did a good but not great job of capturing low-frequency transient and textural details. When I listened to the concert bass drum on “Regular Pleasures” from Patricia Barber’s Verse [Blue Note], for example, the attack of the drum sounded slightly subdued, though its ensuing “boom” and shuddering decay sounded fundamentally correct. Similarly, on Stanley Clarke’s slapped electric bass on the title track of School Days [Nemperor, LP], the sharp, percussive “pops” at the leading edges of notes were rounded-off to a degree, though the bodies of the notes had nearly ideal power and depth. The good news is that the SA-31 consistently puts a firm bass foundation under the music—never sounding anemic down low, as some affordable preamps do. But at the same time, I felt the preamp could be improved if it provided a greater degree of lowfrequency tautness and definition.
Up high the SA-31 sounded sweet, smooth, and silvery, though it was not the last word in reproduction of high-frequency details or of the “air” surrounding instruments. In practice, this turned out to be a mixed blessing. On recordings such as John Abercrombie and Eddie Gomez’s Structures [Chesky, SACD], which features the richly detailed sound of Gene Jackson’s delicately brushed cymbals and drums, the SA-31 sounded generally refined, but it also smoothed over low-level treble details to some degree. However, on recordings such as the Boulez/Chicago reading of Mahler’s Symphony No. 9 [Deutsche Grammophon], whose string passages are apt to sound overly hard or wiry in the first place, the SA-31 turned potentially strident sound into approachably clean, sweet music.