SOtM took pains to distinguish their product from the rest of the D-amp pack, thus Mr. Lee's design exhibited a very distinct voicing in the footsteps of classics like the BBC LS5/9 loudspeaker. The sPA showed a passionate core balance that was unshakably midrange centric. Regardless of combination, the ear's attention was consistently pulled into this range, offering a vivid presentation grounded in the unamplified concert hall experience more so than recorded trickery. While D and T amps like the Audio Zone and Bel Canto EVO 200.4 can be tweaked to approach this level of midrange vividness, the SOtM accomplished it out of the box. Male and female vocals were articulate and uncolored without lower mid/upper bass overhang or sibilant excess. Acoustic instruments likewise were richly detailed, prioritizing a warm balance that relegated frequency extremes to being cohesive rather than overtly separate. Bass gave a powerful underpinning and the upper octaves were remarkably refined though a little polite. While this tonal balance somewhat darkened hall information and reduced upper octave air, it automatically opened up a wider catalog of recordings for musical enjoyment.

Performance on the dynamic front proved consistent with the medium power rating blessed by graceful clipping. I never felt the sPA1000 was taxed despite my speaker's relatively low 85dB efficiency and the amp provided sufficient SPL with adequate dynamic peaks to satisfy my listening requirements. Noise was quite low thanks to balanced circuitry to result in performances emerging from a velvety dark background. Low volume retained the same tonal character but required somewhat higher threshold levels than my Bel Canto EVO 200.4 or Audio Zone D-2 to kick into dynamic life. At the opposite end of the scale, the gentle overload character expressed itself similar to low/medium power tube amplifiers, with unobtrusive compression revealing a wealth of low-level detail as volume increased without noticeable noise penalty. Detail and dynamic acrobatics were prioritized in the midband, imbuing performances with vibrant expressiveness but rendering fine detail especially in the high frequencies more incidental than pronounced.

The SOtM's responsiveness fell into the tubular mold, generous with trailing edge information but somewhat soft on steep transients. Transistor fans may find the performance a touch understated but tube aficionados will find it fast enough. The addition of outboard vibration management altered the transient and tonal character to some extent. The KAT Terminator 1 isolation feet benefited transient attack at the expense of midrange vividness. The EquaRack footers expanded on the core tonal balance of the SOtM feet and split the difference in responsiveness. As a comparative reference for dynamic behavior, the Bel Canto EVO 200.4 and Audio Zone D-2, showed a bit more transient snap and overall dynamic exuberance, partly by design and partly from considerably higher power.

The sPA1000's handling of soundstaging and imaging complemented its live unamplified tonal balance, offering a concert hall perspective where distance and location cues were never razor sharp but subtle and somewhat diffuse. The overall effect was quite seductive, appealing straight to the heart by placing primary emphasis on musical content not context. The SOtM's handling of context however demanded critical analysis. Comparatively, the sPA1000 was superior to both the Bel Canto EVO 200.4 and Audio Zone D-2 in providing rock-solid center fill but fell slightly short of their Cinerama width. The illusion of depth from all three amplifiers was roughly comparable but the SOtM exhibited somewhat less projection and dimensionality. Image focus with the sPA1000 was on the soft side, reducing localization of instruments, slightly compressing distances between objects as well as diminishing hall cues. It should be noted that outboard resonance management especially with the EquaRack footers improved localization, projection and focus to push closer to the Audio Zone D-2.