Phil Gold’s review of the Musical Fidelity M6x digital-to-analog converter appeared on this site on July 15. In his review, Phil explained that the M6x, which is priced at $2500 (all prices in USD), “replaces the M6sR, which itself replaced the M6s, one of the first DACs to use ESS Technology’s Sabre ESS 32-bit HyperStream II architecture.” The brand was founded by classical clarinetist Antony Michaelson in 1982, but Phil pointed out that Michaelson “sold Musical Fidelity to Audio Tuning Vertriebs GmbH, parent company of Pro-Ject Audio Systems, and returned to his first love, making music” in 2018.
Phil noted that the M6x DAC “features a pair of ES9038Q2M chips in dual-differential mode, for a dual-mono design,” and added that it “employs the latest version of Musical Fidelity’s Super Silent power transformer, an encapsulated toroidal transformer with low core saturation, fed from an industrial-grade power socket with an EMI filter and a DC blocker.” In his review, Phil explained:
The M6x is not a streaming DAC, but it accepts a range of digital inputs: two optical and one coaxial S/PDIF, USB, and AES/EBU. . . . The USB input supports resolutions up to 32-bit/768kHz PCM, DSD256 DoP, and native DSD512, while the other four support PCM up to 24/192. Full support is provided for MQA.
The M6x has seven digital-filter options, with Musical Fidelity suggesting users start with the first filter option—described as linear phase, fast rolloff—before testing the others. Phil preferred the third filter option—minimum phase, fast rolloff—and used that for the course of the review.
The M6x has both balanced and single-ended connectors on its rear panel, with fixed and variable output available for both types. Phil used the balanced connections and preferred the fixed-output option:
Musical Fidelity does not make a big fuss about using the variable output to directly drive a power amp and neither should you—it works. But it’s not easy to adjust the volume in small increments from the remote control, and you can’t see what volume level you have set. The signal quality of the variable output, balanced or unbalanced, is well below that of the fixed output in resolution and dynamic range. Routing the audio signal through the DAC’s volume-control circuitry thinly veiled the sound, making it less immediate and involving. I therefore used the fixed output for this audition, adjusting the volume on my EMM Labs Pre2 preamp instead.
Phil’s reference DAC also comes from EMM Labs—the DV2, which retails for $30,000—and, like the M6x, has a built-in volume control, though he typically uses its fixed output.
Starting his listening session appropriately with “Antony Michaelson’s beautifully recorded performance of the Mozart and Brahms clarinet quintets, a rereleased 1999 CD (Musical Fidelity MF014),” Phil soon realized that the M6x is a topflight DAC:
Much to my disbelief, I could barely tell the difference between the DV2 and M6x DACs. Both offered superb tonality and articulation, full bandwidth, and spectacular imaging. Most unusually, the M6x DAC exhibited no audible high-frequency rolloff, allowing that gorgeous clarinet sound to be reproduced brilliantly. There was no trace of harshness either. The DV2 had a slight edge on the M6x, however, in the greater specificity of its imaging.
More classical selections proved the M6x’s excellence. Phil streamed “an outstanding new recording of music for strings by Vaughan Williams, Howells, Delius, and Elgar, played by the Sinfonia of London under John Wilson (24-bit/96kHz FLAC, Chandos / Qobuz).” Listening to the final piece, “a vigorous performance of Elgar’s Introduction and Allegro for Strings,” Phil found that it had “a commanding presence through the M6x with rich, powerful sound, leaving no doubt that this is a superb DAC, closely approaching the reference EMM Labs DV2.” With Portrait, a collection of live recordings by the Bavarian Radio Chorus and Symphony Orchestra under Bernard Haitink (CD, BR Klassik 900174), Phil described how the M6x “conveyed the weight of a symphony orchestra in full flight, never allowing the more sonorous instruments to eclipse softer ones, never losing soundstage dimensionality.” Furthermore, Phil once again emphasized that when comparing the M6x to the EMM Labs DV2, he “had to strain to tell the one from the other.”
Most of the other recordings Phil played showed the same level of performance from the M6x, but he noted that “the DV2 did pull away cleanly from the M6x DAC” on a couple of CDs:
This was most evident in “Summertime,” from The Best of Billy Stewart (Chess 088 112 369-2). The M6x DAC performed strongly on this high-energy track, and if I didn’t know better, I’d say it did a perfect job. But I do: the DV2 had greater intensity and more focused imaging. I detected similar but smaller advantages on a few other high-energy recordings, such as “Wristband,” on Paul Simon’s Stranger to Stranger (Concord 088072398030), and “Diamonds on the Soles of Her Shoes,” from Simon’s Graceland (Warner 25447).
Various tracks on Leonard Cohen’s final album, You Want It Darker (Columbia 88985365072), which Phil listened to via CD, also brought out slight differences in realism and “soundstage dimensionality and imaging precision between the DV2 and M6x.” But Phil also noted that “both DACs delivered this album superbly.”
Phil used his Sony MDR-Z1R open-back headphones to evaluate the M6x’s ¼″ headphone output, which is on the front panel. Alternating between his speakers and headphones, Phil heard “a very close match,” which he called “a rare achievement.” Comparing the M6x DAC’s headphone output to his Graham Slee Solo Ultra Linear Diamond Edition headphone amp, Phil found that “the Z1Rs sounded much cleaner, more natural, and more musical when driven by the Musical Fidelity.” Phil’s conclusions speak well for the quality of the M6x’s headphone output.
At the end of his review, Phil declared that the M6x “really surprised” him, explaining that “very few DACs from just five years ago could hold a candle to it in sound quality.” Phil went on to say that he’s heard “marginally better sound from much more expensive DACs,” but he’s “yet to hear a DAC at this price level with such natural and realistic sound across such a broad range of music.” Phil proclaimed: “From a price-performance perspective in this crowded, competitive field, the M6x DAC stands out.” We agree: the M6x received a Reviewers’ Choice award when Phil’s review was published, and it’s receiving our Recommended Reference Component award this month. The M6x is a superb DAC.
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