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Maximinus. Though the machine's €24.000 sticker exceeded my overachieving Metrum Hex by a whopping eight times, I was too cynical to expect a dead-obvious giveaway. After a prior encounter with a discrete R2R DAC at twice its cost, I'd still favored the Hex. I'd thus gone Dutch when the time came to vote with my wallet. Expecting that I'd need maxiplus resolution because what separates digital these days has gotten lean when one starts off with a Hex, I rebuilt my system to Nagra Jazz, SIT1 monos, soundkaos Wave 40 speakers + Zu Submission sub as the best on hand. Like the Thrax the Metrum eschews I/V conversion and a conventional output stage. It duplicates much of Rumen's concept*. The main difference is that the true dual-differential Hex parallels eight industrial R2R chips per channel to generate 4Vrms on its XLR outputs. The Maximinus uses discrete resistor ladders but only makes 1Vrms on its mixed outputs. It's convenient to believe that higher voltage gain has no effect on sound per se but ownership of Esoteric's C-03 preamp whose gain can be set from 0dB to 12dB to 24dB has proven otherwise.
with SOtM dX-USB HD (super-clock upgrade) + mBPS-d2s battery supply as 2-box USB-to-S/PDIF converter, PureMusic 1.89b in hybrid memory play, hog mode and 24/176.4kHz upsampling in NOS mode
* Modern DACs fall into either low-rate high-bit ladder-type PCM or high-rate low-bit delta-sigma converters. The first category has the choice of BurrBrown PCM 1704, vintage 16-bit parts or expensive discrete custom R2R ladders as the only ones to do native PCM. 90% market share belongs to delta-sigma chips with built-in oversamplers and modulators which convert from PCM. The most expensive of those use 2.5-bit five-level architectures. When it comes to DSD support as announced for the Thrax, the Cirrus Logic CS4398/4385 and Wolfson WM8741/8742 chips support direct DSD mode without further digital processing. This makes them true native or 'NOS DSD' converters. Others use processing like digital volume with PCM/delta-sigma conversion and noise filters. How do native PCM processors handle DSD?

My direct and level-matched A/B comparisons confirmed initial cynicism. Once one cracks the perception barrier of ever-escalating sample rates, bit depths, clever digital filters and actual vs. claimed resolution, many assumptions about how any of it relates to actually sitting in the listening chair go up in the smoke of wishful thinking. The difference here was so minor as to require extensive switching to lock down pat. It was essentially elusive during the beginning of tracks when a background ensemble still set the stage for an instrumental or vocal soloist. Once center stage was occupied, the Thrax proved to be a skoch warmer, the Metrum a touch more quicksilvery and immediate. The scope of this difference was very narrow and of the sort which playing with digital filters or various upsampler modes in PureMusic or J.River creates.


Here a deck like the Hex which lacks selectable filter options can very cheaply retaliate in player software to level the playing field. Because I was a bit shocked by this, I asked my wife to sit in. Playing her music she likes—Concha Buika, El Cigala—and switching decks whilst returning to the beginning of a track and resetting preamp volume, she eventually identified exactly the same very small flavor shift without knowing hardware identities. Asked which if any presentation she preferred, she unhesitatingly picked the more immediate reading. When asked why, she said because it gave her goose bumps. That was the Metrum Hex. On whether she felt one was unambiguously better or worse, she shook her head no. My own feelings precisely!


Altering Thrax's filter settings, I could shift this small difference directly on the machine. The Hex was fixed. This gave the nod to the Dionysos for greater voicing flexibility. Had my iMac interfaced with it properly, would Rumen's Swiss Edel USB module have made a more decisive difference? Prior experiments with USB bridges from April Music, battery-powered Audiophilleo and KingRex, Resonessence and Weiss suggest that my current two-box SOtM performs at the very top of the external heap. I thus doubt it. Exactly like the Metrum Hex, the Thrax Maximinus pulled off that rare trick of sour, sweet and earthy in equal doses - transient sharpness, decay generosity and tonal fullness as our musical take on Thai cooking which combines three or more opposing/complementary flavors.

Appropriating verbatim descriptions from my Hex review, rhythmic articulation is keen like tapping glass with long finger nails. Yet that PRaT precision is followed by highly developed tonal hues and body. This avoids bleaching and prevents high transient fidelity from compromising timbres and textures. When violins and other non-blown instruments exhibit that peculiar singing quality, I see it connected to flow and timing. This the Thrax did very strongly. It also centered things back from the leading edge onto the bloom portion without causing even minor fuzziness on attacks. Zing and song if you will though the second quality very much alters how one perceives the first.


If we compare the textile sound of paper cones and silk domes versus the metal sound of Beryllium, ceramic, magnesium and titanium drivers, it points at this core difference. It's between metallic attack mode and how textile drivers tend to emphasize sounds slightly behind the leading edge. In tube terms it's triode vs. pentode, 2nd-order vs. 3rd-order harmonic emphasis. Here the Thrax is about equal opportunity. It does both at the same time. The instrument which combines these opposing qualities to a similarly broad degree is the piano. The initial hammer fall particularly when vigorously executed is all about metallic wiriness whilst immediately following is the resonance excitation of a huge cavity which can spell big tone.

Close miking and Flamenco/Cuban-style hammer playing can exaggerate the percussive elements. Far-field miking and languorous Chopin legatos shift the balance into the bloom/decay aspects. The Thrax excelled at nailing the metallic hammer falls and the follow-up response of blooming woody resonance with all its scintillating overtones. To conclude, what the Dionysos fundamentally had over the Hex which in early 2013 remained my favorite converter was its modular architecture for future proofiness and a luxury casing. Whether that ameliorates its wildly steeper price when I heard absolutely zero sonic advantages will be for prospective owners to decide.