In the midband, the S.M.S.L. was quite clean, giving vocals and instruments an uncluttered presentation. The ESS-based Auralic, Ayazi and Wyred4Sound were roughly on a similar tonal playing field but ascending and descending the frequencies from that point, differences were obvious. The M400 played it leaner in the lower mid through bass where the ESS DACs turned a little more romantic and prominent. As a result the M400 traded some bass power for greater articulation. As frequencies rose, the S.M.S.L. continued the clean streak, offering a subtly pronounced upper mid through treble that accomplished a delicate balance of apparent extension and non-etchy smoothness. By comparison, the Auralic and Wyred were a touch rougher in the upper mids and less refined in the highs. Deep bass was more or less equivalent. In a nutshell, the ESS DACs favored the mids on down, the M400 the mids on up to give the AKM a drier more illuminated feel. The degree to which this dominated was somewhat amplifier and cable dependent. Warmer cables toned it down. Cables emphasizing the upper registers pushed that leanness further. Partnered with a relatively neutral cable, the Audio Zone took the signature into a studio-dry unembellished factual scenerio. The SOtM steered the balance a bit more into tube-rich territory, darker on top, more romantic and corpulent in the lower octaves. One appealed to the engineering intellect, the other to the music lover's heart.

In terms of resolution and dynamics, the M400 followed its own tonality. That mildly lean character emphasized broadband detail, offering tremendous punctuation of transients especially in the upper octaves. This lent a lively rendition to string and brass material and spotlighted articulation on vocals. Bass authority and large dynamic swings there were less than the ESS alternatives especially the Wyred. That could deliver unmatched massive LF clout. But the M400 was consistently cleaner, offering more microdynamic information about instrumental character. An area where the S.M.S.L. shone was in separating the dynamic and tonal structure of individual performers and instruments in dense musical passages. Here it matched the in-house competition as well as considerably more expensive DACs I've come across.

The soundstaging and imaging of the M400 further exposed stylistic differences and revealed sonic inconsistencies of amplifier matching. Paired with the Audio Zone, the front of the soundstage started behind the speakers with minimal projection but good depth, adopting an observational rather than immersive stance. The SOtM played a little more nearfield, trading off some depth to achieve greater immediacy. The ESS DACs demonstrated more projection irrespective of amplifier and also slightly better width. Performer placement and venue information were dictated by the amplifier. With the Audio Zone, the M400 demonstrated image focus and specificity in the lateral plane that was exceptional, keeping pace with the best the others had to offer but diverged on depth. The M400 separated instruments and vocalists into clearly differentiated layers of distance but afforded them less dimensionality than the competition. Reproduction of venue information took its cue from the M400's treble tonality. The Audio Zone illuminated a hall of vast proportions whose boundaries were more implied than defined. It succeeded in delivering a wealth of information about the space but did not fully realize it. The ESS variants managed a more fleshed-out recreation of performers and venue.

The SOtM/M400 combination conjured an alternative version of the same events and served as reminder that different musical partners bring different results. The sPA1000's richer tonal balance automatically built a world with greater density for all the DACs on display, adding more weight in the lower octaves and delivering a darker venue. But where the M400 had played the brighter tones with the Audio Zone, it took opposite tack with the SotM to push that richness a touch further than the ESS alternatives. The M400 portrayed the venue in even darker hues, offering less hall boundary information and pushing the furthest reaches into deepest black. On imaging however, this pairing matched or exceeded the competitors. Gone was the coyness of dimensionality. It had been replaced by individual instruments and vocalists wonderfully focused in both the lateral and depth planes, parading pronounced solidity and spatial separation within the stage. As a final bonus, the SOtM/M400 combo also achieved the magic trick of making the speakers disappear as apparent sound sources, leaving only the illusion of performers and recording venue to grace the listening room.

On that high note, my experience with the M400 is pretty much documented so it's time to wrap up. S.M.S.L. succeeded in creating a sonically refined DAC with a distinct character that can serve as a serious component either with a preamp or alone. The M400 unleashes the capabilities of a top-end DAC chip in an intelligent package and does so at an aggressive price. Matched properly, it combines high resolution with an ultra-clean top end and only bows to pricier competition on bass power and soundstage sophistication. The M400 DAC is a diamond in the rough and if handled with care, will deliver high performance above its low cost. Pedestrian treatment will yield pedestrian results but polish this little diamond with the proper ancillaries and it will shine. Bargain hunters take note. One pair of quality interconnects for the direct-to-amplifier connection will cost a fraction of the price of multiple runs plus separate preamplification. If you don't need more input flexibility or gain and are willing to live without that last degree of performance, there's some gold to be mined. Now on to our second offering from S.M.S.L…