Last month, Roger Kanno’s review of the NAD Masters M66 streaming preamplifier appeared on this site. In his review, Roger notes that the M66 was meant to be a companion to the Masters 23 stereo/mono amplifier, which he reviewed in March of last year, pointing out that it complements the M23 in both aesthetics and performance. The M66 and M23 are respectively priced at $5499 and $3749 (all prices in USD).
The M66 “offers a scope of features rarely seen in this type of component at any price,” Roger writes, noting that “in addition to a high-performance DAC with a separate analog preamplifier section, you also get the BluOS multiroom streaming platform, Dirac Live Full Frequency room correction, and Dirac Live Bass Control for up to four independent subwoofers. Not to mention a high-quality MM/MC phono stage, a headphone output, and pretty much every other feature you could ask for in a streaming preamplifier.”
The back panel of the M66 is “brimming with inputs and outputs,” Roger writes. Digital inputs include two coaxial (RCA) and two optical (TosLink) jacks, one AES/EBU (XLR) connector, and one HDMI eARC port. Bluetooth and Wi-Fi support allows wireless connection. Line-level analog inputs include one pair of balanced (XLR) connectors and two pairs of single-ended (RCA) jacks, as well as two pairs of phono (RCA) jacks: one for MM cartridges, one for MC. The M66 also sports two pairs of analog outputs—one single-ended (RCA), the other balanced (XLR)—and, unusually, two sets of four subwoofer outputs: one set single-ended (RCA), one set balanced (XLR). The M66 comes with a license for Dirac Live Bass Control (Multi-Subwoofer), which permits seamless integration of one or more connected subs with the main speakers. This combination of multiple subwoofer outputs and Dirac Live Bass Control has attracted a lot of attention. Very few preamplifiers on the market offer such a complete, flexible solution.
Many buyers will pair the M66 with the M23 power amplifier. Some will pair it with two M23s, each bridged to mono. But the M66 can be paired with almost any power amplifier—or pair of monoblocks. Roger’s own reference system, in fact, includes a pair of Anthem M1 monoblocks, which he used for part of his listening. He did most of his listening with the M66 feeding a pair of M23s in bridged mode.
Our bench-test measurements of the M66, which accompany Roger’s review, revealed a potential preamplifier-amplifier matching issue to be aware of: when the M66 is operating in Analog Direct mode, which bypasses its internal DSP (digital signal processing) functions, its gain is relatively low. Diego Estan, our measurements specialist, measured −3.6dB of gain from the single-ended outputs (indicating signal loss) and just 2.7dB of gain through the balanced outputs. Since most analog preamplifiers provide at least 6dB of gain, these figures suggest potential compatibility issues. But with Analog Direct turned off, which is how the M66 is likely to be used and is how Roger used it for his review, gain was measured at 2.6dB and 8.6dB for single-ended and balanced connections—lower figures than the 8.63dB and 14.89dB claimed by NAD, but high enough that amplifier compatibility shouldn’t be an issue.
Diego describes a couple of other minor issues in his write-up, but overall, he found the measured performance of the M66 to be excellent. Noise and distortion levels with both digital and line-level analog inputs (whether or not Analog Direct mode was on) were extremely low. Phono-stage performance on the bench was not as impressive, but it was still acceptable. Interested readers are encouraged to peruse the measurements page for details.
Roger characterizes the sound of the M66 as “neutral and transparent” and likens it to that of the M23 and the Lyngdorf MXA-8400 multichannel amplifier, which he reviewed in June and now owns. The M23 and MXA-8400 are both based on Purifi Audio’s cutting-edge Eigentakt amplifier technology, which has been held in high regard for providing exceptional sound quality. Roger describes “Raiders March (From Indiana Jones and the Raiders of the Lost Ark),” from John Williams: The Berlin Concert, as follows: “the pulsing notes of brass, strings, and timpani were imaged precisely on a broad soundstage, imparting a sense of the expanse of the physical stage at the Berliner Philharmonie concert hall, where this recording was made. The strikes of the timpani lingered ever so slightly but were still taut and drawn with precision. The cymbals, barely audible, still rose clearly from the horns in the background. This was followed by the sharp snap and staccato of the snare, which contrasted with the more fluid sound of the timpani.” On other, less complex recordings, such as the Fine Young Cannibals’ cover of Elvis’s “Suspicious Minds (Caught in a Dub),” he found the sound to be “surgically clean.”
Those two tracks were digital. Moving on to vinyl, Roger observed that his pressing of Fleetwood Mac: Greatest Hits had less surface noise than he usually hears. Christine McVie’s and Stevie Nicks’s vocals, he adds, sounded “extremely clean and clearly separate from the instrumental accompaniment.” Bruce Springsteen’s Tunnel of Love, “another less-than-perfect-sounding LP” of his, sounded its very best, Roger writes. “Sibilance was tamed enough not to be distracting but not so much as to soften Springsteen’s voice and render it indistinct. The sound was always clean, never harsh, and was imbued with satisfying weight and substance.”
Roger also tested the M66’s headphone output (as did Diego, who detailed his findings in the measurements section) and found it to be “outstanding,” though not “quite as full-bodied and powerful” as his desktop reference: a JDS Labs Atom headphone amplifier combined with an Apple USB-C dongle. Comparing the M66’s headphone output to that of his Oppo UDP-205 Blu-ray Disc player, he found that with the M66, “vocals were notably more detailed and distinct, and therefore more intelligible, but still smooth and highly musical.”
The Anthem STR preamplifier, which has served in Roger’s reference system since its introduction in 2017, is a strong competitor of the M66. However, it lacks the latter’s wireless connectivity, streaming capability, color touchscreen, and headphone output. But it does offer a number of other important features: a built-in DAC; an MM/MC phono stage; one pair each of single-ended (RCA) and balanced (XLR) subwoofer outputs, for connecting one or two subwoofers; room correction via ARC (Anthem Room Correction), which can smoothly integrate one or two subs with the main speakers; and a home-theater bypass function, something the M66 lacks, which Roger deems invaluable. Like the M66, the Anthem STR offers numerous analog and digital inputs and outputs.
We’ve praised the STR over the years for its sterling sound quality and its forward-thinking feature set—when it was introduced, no other company we know of offered a high-performance two-channel preamplifier with subwoofer outputs and subwoofer-compatible room-correction software. Having compared the Anthem STR directly with the M66, Roger gave the nod to the latter for its quieter background, broader soundstage, better definition and clarity, and deeper and more articulated bass. The M66 lacks home-theater bypass, but it has a richer feature set otherwise.
In his review, Roger points out that “since its inception in 2005, the NAD Masters Series range has been populated with the company’s finest audio components at relatively reasonable prices.” The M66, like the M23, is no exception. “I cannot think of another product at a comparable price that comes close to the M66 in performance and flexibility,” Roger pronounces in his conclusion, “let alone one that surpasses it and is more deserving of my recommendation.” Both Masters components received Reviewers’ Choice awards at the time their reviews were published for high value and outstanding performance. It was its outstanding performance that, later, earned the M23 a Recommended Reference Component award, and it’s now the M66’s turn, for its stellar performance, to receive this same award.
Manufacturer contact information:
NAD Electronics International
633 Granite Court
Pickering, Ontario L1W 3K1
Canada
Phone: (905) 831-6555
Fax: (905) 837-6357
Website: www.nadelectronics.com
