Reviewers' ChoiceFirst, the elephant in the room: EMM Labs’ MTRX2 mono amplifier sells for $85,000 USD per pair. What’s more, it’s the baby elephant of the two power amps EMM makes -- the MTRX Reference costs $130,000/pair. Those prices are so high that, for the vast majority of audiophiles, including me, these amps are impossible to buy new.

Some might question the need to review a product that’s so far out of reach of almost everyone. It might also raise eyebrows about why this review appears here on SoundStage! Hi-Fi and not SoundStage! Ultra, which focuses on higher-priced gear. There are a couple of reasons: First, SoundStage! Hi-Fi is the only SoundStage! Network website that covers hi-fi across all price ranges. Another reason is me: I now review equipment only for this site, and I’ve always been interested in hi-fi gear of all types, shapes, sizes, and prices. But the most important reason, is that the MTRX2 represents the latest thinking of EMM Labs’ founder, Ed Meitner, whose creations I first heard in the 1980s, when he was designing for Museatex. In particular, I fell in love with Museatex’s legendary Meitner MTR-101 mono amplifier. A compact, relatively affordable amplifier specified to output 100W into 8 ohms, the MTR-101 combined cutting-edge engineering -- e.g., its Floating Charge Power Supply -- with décor-friendly appearance and top-drawer sound. Its appeal among audiophiles was immediate, and three decades later it’s still popular with collectors.

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So I just had to see what Ed Meitner is doing with amplifiers these days -- no matter how much they cost.


As you’d expect in so costly an amp, the MTRX2 is powerful -- its circuitry, fully balanced from input to output, is “conservatively rated” (EMM’s words) to deliver 500W into 8 ohms or 1000W into 4 ohms from its MOSFET-based output stage, and is claimed to remain stable into a speaker of almost any impedance, even if it dips below 1 ohm.

It’s also big and heavy. Each MTRX2 measures 21.4”W x 11.7”H x 23”D and weighs 180 pounds -- so big that when I set them down next to Constellation Audio’s Revelation Taurus Mono amplifiers ($40,000/pair), which I reviewed in December 2017, the Constellations looked small. (Thankfully, I didn’t get the MTRX References, each of which measures an almost comical 21.4”W x 13.8”H x 30.1”D and weighs 220 pounds!) In fact, the MTRX2’s size and weight caused me a bit of a problem: My listening room is on the third floor of my house, and I’m 54 -- my days of lifting the heavy things I hefted 20 years ago are behind me. I didn’t want to risk damaging these amps -- or myself.

From what I understand, at the EMM Labs factory in Calgary, Alberta, they use car-engine lifts to ease their work on the MTRX2 and MTRX Reference. I don’t have an engine lift. Thankfully, Ed Meitner’s son, Amadeus Meitner, arrived to help me out. Amadeus, half my age and skinny as a rail, is over 6’ tall, with long arms that give him some flexibility in getting under big things, to carry them more comfortably. He told me he could lift each MTRX2 all the way up if he had to -- but he didn’t want to risk dropping and breaking an amp any more than I did. We recruited a neighbor’s 16-year-old kid to help Amadeus, but at the last minute he backed out, fearing that if he dropped an amp he’d be grounded for life. So I was still in for part of the labor. Amadeus took the heavier end of an amp and the harder position: in the lead, climbing the stairs backward. Sweating, we eventually got them safely in place, but it wasn’t easy -- if you buy a pair, consider yourself warned.

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I can’t say I much liked the MTRX2’s big, blocky look, compared to the proportions of the Constellation Taurus Mono, whose race-car-like shape I find ideal. But I loved the EMM’s standard color scheme: most of the case is a silver-white that contrasts perfectly with a dark-gray panel at the center of the faceplate. For the same price, they also offer an all-black-anodized finish -- in photos, it looks stealth-like. For an upcharge of $5000/pair, that front-panel insert is available plated in 24K gold -- too bling for me.

Finishes aside, the quality of the MTRX2’s metalwork is among the best I’ve seen or laid hands on -- the finely textured metal surfaces felt like suede. The joins of my review samples were perfectly aligned, and all edges, as well as the deeply engraved EMM Labs logo and “Meitner Design” tag, were free of rough edges. The On/Off button for daily use is elegantly disguised as a square that’s part of the logo on the front panel.

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Around back, all labeling other than the voltage rating is subtly engraved into the raw aluminum, which shines a bit brighter than the finished surface it’s cut into, for ease of reading. The balanced (XLR) and single-ended (RCA) inputs seem of good quality, if nothing extraordinary; however, the speaker binding posts are two sets of Furutech’s high-quality Torque Guards, which can be tightened down hard to clamp spade lugs with no worries about stripping. The main power control is not a simple rocker but a circuit-breaker switch -- turning it on puts the amp in idle, to keep key parts of its circuits warmed up, this mode indicated by a wide red light under the faceplate’s central panel; when the amp is fully activated by pressing the front-panel On/Off button, this light turns blue. (If you hold down the On/Off button about 4 seconds when powering on, the light will flash blue several times, then go dark and stay dark when the amp is warmed up and ready for action.) The power-cord inlet is of a type that was new to my room -- a big, round, industrial-grade, high-current model. EMM Labs supplies a high-quality power cord with each MTRX2; if you want to use your own cord, you can, though it will need a compatible connector.

When Amadeus Meitner helped me install the MTRX2s, he removed one amp’s top plate to let me look inside. But wanting to learn more about the makings of the MTRX2, I scheduled a call with Ed Meitner. I’d spoken with Meitner before, and it hadn’t been easy. His knowledge of electronics design is encyclopedic and dates back to the 1970s, before he got involved in hi-fi, when he designed recording consoles and test instruments. However, he’s reluctant to talk much about his work, and when he does, he can be terse if asked a question he thinks is silly or uninformed. I sometimes got the feeling he was about to tell me off . . . or just had.

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This time, Ed Meitner and I seemed to get along famously. We talked for over an hour, which Amadeus told me afterward “never happens.” Still, I can’t say that, in terms of the MTRX2’s technical aspects, I learned much more than you can read on EMM’s website. The specs published there state that the MTRX2 has no global feedback, has an A-weighted signal/noise ratio of >120dB, intermodulation distortion of less than 0.005%, total harmonic distortion plus noise of less than 0.005% from 20Hz to 20kHz at full rated power, a damping factor of over 1000, a slew rate of more than 100V/μs, and a frequency range of DC-500kHz at full rated power. However, he did tell me his reasoning for that last spec of extremely wide bandwidth: “Faster transient response, for a clearer and more open sound.”

When I tried to learn more about the MTRX2’s technical aspects, Meitner was reluctant, even when I asked him for details about the cream-colored ceramic circuit board, like those found in his preamps and DACs, that occupies the top-rear center of the MTRX2’s interior -- a board that, his son had told me, is “really important” for the amp’s performance. Meitner senior shrugged it off with a simple “It’s the voltage amplification stage” and said little more.

EMM Labs

Yet he was forthcoming about his overall goals for his amps and his other products. Meitner feels that any true high-end hi-fi product must be engineered in its entirety: you can’t shop out any part of the design, such as the off-the-shelf amplifier modules seen in so many of today’s class-D amps, or even a DAC module. “That’s not engineering!” he declared. It’s why he makes his own discrete, single-bit DACs, and why his handiwork is visible in every aspect of every circuit of every product he makes.

Meitner also told me that, because the MTRX and MTRX2 are the first amps he’s offered for sale in a long time, he needed them not only to sound perfect but to be perfect in every other way. He wanted them to function flawlessly, with no operational glitches -- and sure enough, I encountered no such problems with the MTRX2s. He also wanted them to be bulletproof in terms of safety and reliability. Built into both models is what Meitner calls a “comprehensive monitoring system” that looks at operating temperature, DC offset, overload conditions, etc. This system shuts down the amp should any sort of fault occur, so as not to damage any connected speakers. Should a fault happen -- and again, none did while the EMMs were in my system -- Meitner said that the front-panel illumination reverts to red. The user should then push the front-panel On/Off power. If the fault condition is fixed, the amp will power on again.

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Meitner also wanted the MTRX and MTRX2 to be compatible with any speaker on the market. To guarantee this, they had to not only have high enough power output, but be able to deliver that output to speakers of any impedance with no variation in distortion characteristics -- hence their stability to below 1 ohm. That’s something that’s not characteristic of most amps, as is clear in measurements, which often indicate how the level of distortion changes with the load. Finally, Meitner told me that he doesn’t design electronics to reproduce music -- he creates them to reproduce sound. His belief is that a component shouldn’t itself be some sort of musical instrument; instead, it should simply pass along any signal it’s fed with complete transparency.


Along with the MTRX2s, EMM Labs also sent me a DA2 Reference DAC ($25,000), which I’d reviewed in July 2017, as well as the companion Pre preamplifier ($25,000), which I welcomed -- I could compare it with my reference preamp of several years now, the Simaudio Moon 740P. I found both preamps to be compatible with the MTRX2s, and highly resolving of the smallest musical details. But the Pre offered a bit more soundstage dimensionality and overall body to the music, so I used it for my listening sessions. (I hope to do a more thorough write-up of the Pre in the future.) They also sent their own Isopath speaker cables and balanced interconnects to try, though I used only the interconnects between preamp and amp, and only after first comparing them to my reference Crystal Cable Standard Diamond interconnects, to ensure that nothing would be compromised. However, I used my other Standard Diamond interconnects to connect the DA2 Reference to the Pre, and my Siltech Classic Anniversary 330L speaker cables for the amps and speakers, because I didn’t want to change anything else. The source was my Samsung R580 laptop computer running Windows 10 and Roon, connected to the DA2 Reference with an AudioQuest Diamond USB link.

The MTRX2s’ stock power cords were plugged into a Shunyata Research Venom PS8 power distributor, itself plugged into a 20A dedicated outlet via a Shunyata Research Venom HC cord. The DA2 Reference and Pre were armed with Venom HC power cords and plugged into another Venom PS8 distributor, which also has a Venom HC cord connecting it to another 20A dedicated outlet.

EMM Labs

I used the MTRX2s to drive pairs of Revel Ultima2 Salon2 and Muraudio SP1 loudspeakers. The Salon2 ($21,998/pair), a four-way speaker with six dynamic drivers, has a slightly below-average sensitivity of 86.4dB/2.83V/m, which can be a somewhat difficult load for some amps to drive due to its lowish impedance. The SP1 ($14,700/pair) is a two-way hybrid speaker with one electrostatic panel, four dynamic drivers, and a sensitivity way below the average: 80.5dB (though because the SP1 is partially a dipole speaker, its in-room sensitivity is somewhat higher), with a nominal impedance of 8 ohms -- not too difficult a load. You just need a lot of power to get it to play loud. Which I’ll explain . . .


With the MTRX2s in charge, I could play the Muraudio SP1s loud -- as loud as I dared to, anyway. Designer Murray Harman told me that the SP1 can output 103dB at 2m, but cautioned that if I did reach its limit, it would fail “spectacularly” -- sparks, smoke, and all that. So I was careful. Based on the SP1’s low sensitivity, I estimated that they’d need at least a few hundred watts to approach the extreme SPLs I drove them to -- remember, every 3dB increase in SPL requires a doubling of amplifier power. So when the SPL at my listening seat approached 100dB from 2.5m away, I must have been taxing the MTRX2s at least somewhat, but I couldn’t tell -- had their front panels been faces and not plates, they would probably have yawned. The MTRX2s sounded as if they were coasting the entire time.

Recently, people have written in to tell me they’ve heard that the Ultimat2 Salon2 is a real power hog -- but as I’ve written in our “Feedback” section, I haven’t found that to be the case. Yes, you need fairly high power, but amps that put out 200 or 300Wpc into 8 ohms will usually do for rooms of typical size. As a result, I found the MTRX2s’ 500Wpc overkill in my large space -- when I turned the volume up, I felt I would probably have blown up the speakers long before the amps tapped out. Bottom line: The MTRX2s could deliver high amounts of power.

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They could also deliver supreme bass weight and woofer control, as became obvious when I played the Cowboy Junkies’ The Trinity Session (16-bit/44.1kHz FLAC, RCA Victor) through the Salon2s and heard the ultra-deep bass-drum whumps in the bottommost octave reproduced with super tautness. Did having all that power on tap impress me? A little bit -- that kind of output capability meant that the EMMs were unlikely ever to run out of juice and clip -- that is, distort badly when their peak power-output spec is exceeded. And because very-high-powered amps tend to have an ease and effortlessness of sound compared to amps of lower power, even when delivering only a fraction of what they can at full power, it’s like having a very small car with a very powerful engine. The MTRX2s always sounded supremely at ease. But in other ways, that power didn’t impress me as much as it might have had the Constellation Revelation Taurus Monos not been sitting right alongside. The Taurus monos are also specified to output 500W into 8 ohms or 1000W into 4 ohms, but they cost only half as much as the EMMs, and they controlled the Revels and Muraudios as well as the MTRX2s did.

But high power output was only part of the MTRX2 story. On EMM Labs’ website and in person, Ed Meitner calls each MTRX model a “gentle giant,” and I could hear why. Played at loud or, as I mostly listened to them, low to moderate listening levels, they had a gorgeous, velvet-smooth sound throughout the audioband, and particularly in the midrange: it was rich and sultry with most of my recordings, yet with all the resolution I could hope for. And I do mean all -- the MTRX2s revealed everything. They could also image with tube-like dimensionality, laying out soundstages of depths so convincing they were sometimes uncanny. This was also a bit troubling -- once I heard it, I knew that, when it was time to send these amps back to EMM, I’d miss them bad.

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For example, I like to use Van Morrison’s Poetic Champions Compose (16/44.1 FLAC, Mercury/Tidal) for tests, though it’s a flawed recording. Recorded and released in 1987, it has the somewhat thin sound so common among CDs of that era (my ripped files are from the CD I bought decades ago), along with a wide but shallow soundstage. I played “Spanish Steps” through the Muraudio SP1s. I can’t claim that the MTRX2s provided any more spaciousness than the Taurus Monos -- the two sets of monoblocks were equally extraordinary at accurately re-creating the full width and depth of whatever soundstage a recording possessed -- nor can I say that the MTRX2s sounded any smoother than the Tauruses, which are incredibly smooth. But the MTRX2s did bring out a bit more body and tangibility of the sonic images, and positioned those images on the soundstage with slightly more precision in terms of depth -- with the MTRX2s, what some call the layering of the soundstage was apparent to the nth degree. Morrison’s alto sax in this track didn’t sound all that much different from how it’s sounded to me with a variety of other solid-state amps, but even it seemed to have a bit more body than I’d heard before. The result was a more densely packed sonic image that made it easier to imagine the instrument actually being in my room. Granted, some of that body and tangibility had a bit to do with the MTRX2s’ soulmate, the EMM Labs Pre, but equal measure was due the amps: I could still hear that body from the MTRX2s when I swapped out the Pre for the Simaudio Moon 740P, though it was somewhat diminished by the 740P’s slightly lean sound.

In my review of the Muraudio SP1, I wrote: “When I played ‘Smokestack Lightnin’,’ from Howlin’ Wolf’s Moanin’ in the Moonlight (16/44.1 FLAC, Chess/Tidal), I heard a tightly focused ball of unbelievably clear sound right between the speakers -- Wolf’s voice and the accompanying instruments all wound up nicely, but were reproduced so cleanly that I could easily distinguish each instrument from the others.” Of course, Moanin’ in the Moonlight is a monaural recording -- that’s why the instruments were “wound up nicely” in the center. But it was how well I could still sort out one instrument from the others in that ball of sound -- and even hear a certain amount of depth otherwise buried in this mono track -- that helped me realize that with the MTRX2s driving the SP1s, not only were soundstage images re-created exceedingly well in terms of fixing the images on the stage, the MTRX2s were world champions at conveying the subtlest spatial cues, even in mono recordings.

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A recent discovery I’ve made through Tidal is the singer Chlara’s Evo Sessions (24/96 FLAC/MQA, Evolution Media/Tidal). It’s a very spare, pure-sounding recording of, I believe, only acoustic instruments. Chlara does a beautiful job on track 9, Cat Stevens’s “Wild World” -- mostly because of her earnest and achingly sweet voice, which is pristinely recorded and placed solidly at center stage. Such a recording shows exactly why the MTRX2 can be considered a gentle giant. Sitting on the floor, a pair of them are imposing -- some might even think them brutish because of their big, boxy looks. But powering the Revel Ultima2 Salon2s, they reproduced Chlara’s voice with the utmost delicacy and refinement. The sound had an airy, light quality you wouldn’t necessarily expect from such big solid-state mono amps -- at least if you’re an old-school thinker who believes that high power and high refinement can’t coexist. Yet her voice also had a sense of urgency -- I could feel even her subtlest inflections of note and word, as if she were singing to me in real life. This was even more apparent with “This Love,” which has a livelier, jazzier feel. I don’t like the song nearly as much as “Wild World,” but the EMMs and Revels reproduced her voice with such immediacy and purity that I could only sit and listen, and not criticize -- I was captivated by how realistically and natural Chlara sounded.

Having heard that quality of reproduction of a woman’s voice, I turned to a male singer: Adam Cohen, and his album We Go Home (16/44.1 WAV, Cooking Vinyl). I played the entire album straight through, so engrossed was I with what was coming out of the Salon2s. Immediately afterward, what popped to mind was how well Cohen’s voice had been conveyed -- the EMMs’ velvet-smooth sound and sky-high resolution made it sound so authentic. The next thing that came to mind was that I knew, deep down, that it was this sound’s inherent rightness that had compelled me to listen to the entire album and not think of skipping to another track or album. What rightness in music reproduction means exactly is difficult or impossible to put into words. It’s easier to say that it’s something you experience, and that you know it when you hear it -- not unlike looking at a great painting and having the image take your breath away, but without being able to explain exactly why.

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Finally, I listened to a 2012 remastering of Blue Rodeo’s Diamond Mine (16/44.1 WAV, WEA) through the Salon2s, and when “Nice Try” came up I was floored. The album was recorded in Toronto in 1989, at the Donlands Theatre (Wikipedia says Kingsway Studio in New Orleans, I don’t know why), which originally opened in 1948 as a cinema, closed in 1969, and since then has been repurposed several times, including as a recording studio. “Nice Try” sounded HUGE in my room, the stage extending a couple of feet beyond the speakers’ outer side panels, and with air everywhere between. In the first 90 seconds of this track the drums are positioned at far right, far left, and briefly at center stage. At the beginning of the song, cymbals and drums are lightly struck at far left -- those cymbals sounded shockingly clear, and the position of the drum kit was hyperprecise. More ear-opening was what was happening at the far right of the stage -- as those drums were being struck, I could clearly hear their soundwaves travel across the room, be reflected off the farthest-left wall, then echo and fade out. Hearing so much air around an instrument, combined with such specificity of spatial cues, was astounding.

Later, when Greg Keelor’s voice enters at center stage, it wasn’t confined to a tight ball of sound, as lead vocals are in most recordings -- it sounded larger and more diffuse. If I had to guess, based mostly on what I heard through this system with the Salon2s, the engineers miked a speaker that Keeler’s voice was being amplified through, or they directly miked his voice and a speaker. Whatever the case, it was oh, so easy to hear the musicians and the entire recording space they were in.

But at this point I had to remind myself that there was more at play here than the MTRX2s -- the Pre and DA2 Reference were up front. But still -- all that Meitner gear could map soundstages like crazy.


In the introduction to “Audio Maverick,” an interview with Ed Meitner published in the March 1993 issue of Stereophile, Robert Harley wrote: “Ed Meitner is one of those rare individuals who charts his own course in audio product design.” It was true then and it’s still true now, a quarter-century later. But other things have changed.

Ed Meitner’s Museatex products of the 1980s were small in size, big on style, and priced affordably enough that someone with a good job could save for a while and buy one. His current products, such as the MTRX2, are huge, heavy, and so expensive that only a handful of people can dream of ever owning a pair. But the MTRX2 still has something in common with the MTR-101 monoblock of 30 years ago: It’s a super-desirable product that I have no doubt will stand the test of time, partly for how it’s made, but mostly for how it sounds. It conveys music -- or sound, as Meitner would say -- without colorations and with extremely high resolution, while providing as much power as almost anyone will ever need.

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As for that elephant: There’s no way I can say that $85,000 is or is not a fair price for a pair of mono amps, just as I can’t say that $250,000 for a Bentley automobile is or isn’t a “deal” -- or that spending what some folks spend on high-priced watches is wise or foolish. These are personal choices based on individual perceptions of value. What I can say is that I believe that, in the MTRX2, you’re paying for more than just the build and parts quality. You’re also paying a premium for a non-high-volume, boutique manufacturer to design and make it -- and you’re paying for what only Ed Meitner can design. But once you’ve heard these mono amps, you’ll know that Meitner’s magic is worth something. The EMM Labs MTRX2 monos are the best-sounding amplifiers I’ve ever heard.

. . . Doug Schneider

Associated Equipment

  • Speakers -- Muraudio SP1, Revel Ultima2 Salon2
  • Preamplifiers -- EMM Labs Pre, Constellation Audio Revelation Pictor with DC filter, Simaudio Moon 740P
  • Power amplifiers -- Constellation Audio Revelation Taurus Mono (monoblocks)
  • Digital-to-analog converter -- EMM Labs DA2 Reference
  • Computer -- Samsung R580 laptop running Windows 10, Roon
  • Digital link -- AudioQuest Diamond USB
  • Analog interconnects -- Crystal Cable CrystalConnect Standard Diamond, EMM Labs Isopath
  • Speaker cables -- Siltech Classic Anniversary 330L
  • Power cords -- Shunyata Research Venom HC
  • Power distributor/conditioner -- Shunyata Research Venom PS8 with Venom Defender (2)

EMM Labs MTRX2 Mono Amplifiers
Price: $85,000 USD per pair.
Warranty: Five years parts and labor.

EMM Labs Inc.
115-5065 13th Street SE
Calgary, Alberta T2G 5M8
Phone: (403) 225-4161