GRIMM AUDIO MU2 STREAMING/DAC/PREAMP

I have recounted once or twice across my writings here certain epiphanies that I have had in the high-end audio world. These epiphanies have provided incredible insight, corrected mistaken beliefs, and strengthened my love for audio in its ability to bring music to life, figuratively, speaking, and to bring me back to a grounded reality.

One such epiphany happened in the Mission District in San Francisco many long years ago. I was visiting a woman who would soon become a girlfriend. Her apartment was styled in the motif of the late 1970s—bohemian decor, candles, a rainforest of plants, lava lights, black light posters, black lights, beanbags, etc.—though we were well into the late 1980s.

We sat, talked, and laughed for a long while on a matching pair of yellow beanbag chairs. And when the subject of music came up, she moved with deliberation towards a side table, opened it, and pulled from within an album, an LP—long-playing record—and turned to face me with a wide smile.

I had not seen a record player but there, several feet behind the yellow beanbag chairs and closer to the floor than our “chairs,” was a dusty, might-be-working turntable. While it was not a Kenner Close’N Play, it was most probably an entry-level something-or-other. I chuckled quietly and held back a wisecrack, desperate to be freed. I had long been on the early digital bandwagon and had spent a pretty penny on topnotch digital fare of the time. This was not that.

When she placed the record on the platter, swung the tonearm into position, and dropped the needle, there came a momentary “pop,” and a smirk from me. Then from this dust-covered might-be-working turntable came music as a compelling force and, as I had written earlier, “the music came in waves tactile, sensual, rich” that filled the entire room. And when the warmth of Billie Holiday’s voice made contact as she sang “God Bless the Child” and as the music and her voice wrapped their arms around me, drew me in, I was “stunned-humbled” to stone and momentarily catatonic.

Immediately and beyond any question of doubt, what I had been listening to via my high-end digital fare of the late ‘80s was decidedly not music, not even close. This, which she now played, was music that was inherently more natural, more engaging, more real. I remember closing my eyes, slowly shaking my head, as a single thought crisscrossed my mind: “I have been deceived.” That experience or epiphany set a flight path that quickly brought me back to earth and to vinyl and to real music.

The current review brings me to yet another startling epiphany that, in many ways, turns the table on that earlier experience. The component in question is the Grimm Audio MU2 Streaming DAC. How great is this epiphany?

REFRAIN: Unlike most reviews, this review will be non-sequential, as it will start with how the components actually sound and not the process of physically “undressing” them and/or laying out their various parts, specifications, etc. Think of this review then, as a non-linear movie—Memento, Kill Bill, Arrival, Eternal Sunshine of the Spotless Mind, etc.—that likewise starts at the end and winds its way to the beginning.

The SYSTEM

Grimm Audio MU1 Streamer
Grimm Audio MU2 Streaming/DAC
Exasound s82 Streaming/DAC
Silent Angel Bonn NX Network Switch
Silent Angel Genesis GX Master Clock
Bricasti Design M1SE DAC/Streamer
Lyric Audio Ti-100 MkII SET Integrated
Vivid Audio Kaya 45 Speakers
Kubala Sosna Cables/Wires/Power Cords
RSX Power Cords (Beyond, MAX)
TORUS POWER AVR ELITE Power Conditioner

The Sound

There is “at the forefront” and there is “at the cutting edge and beyond all others.” I spoke of the Grimm MU1 Streamer being at the forefront of digital streaming technology, and there it remains. The Grimm Audio MU2 Streaming DAC, however, is at the cutting edge, synergistically, of both digital streaming technology and Digital to Analog Conversion (DAC) technology. This is no small feat.

Upon placing the MU2 in the system and running a check to see that all was well before run-in, I was forced to take a seat and just listen. Straight out of the box, just off a FedEx “freezer truck,” and still bearing the chill of a Minnesota winter, the Grimm Audio MU2 unfolded or stretched its digital/streaming muscles and put on a performance that to date has no peer. The reference combos—Streamers & DACs—that have long been the mainstay at AKRMedia had, in a way, been put on notice—“There’s a stranger in town and its abilities may well be far superior to your own.” Suffice to say that the combination of these cutting-edge technologies employed within the Grimm Audio MU2 Streaming DAC and the music that issues forth is both formidable and breathtaking.

Once the MU2 had worked out for several weeks in preparation for this review, its performance would require, at the very least, new descriptors to give some idea of its performance and its staggering abilities relative to all others.

The proof of the Grimm Audio MU2’s phenomenal capabilities was in fact hard not to notice. Its transients/microdynamics, blisteringly fast, provided musical attacks with the power and the speed and the gravitas that freed the MU2’s rendering abilities from the constraints with which its competition unfortunately remains saddled. And these constraints speak to any number of “veils” that obscure one’s music regardless of dollars spent.

The MU2’s transparency, its resolution, its ability to excavate and deliver all required detail from stream after stream was not simply a matter of lifting veils. No, that would be an understatement relative to the MU2. What it did, in terms of transparency, resolution, and detail retrieval, figuratively speaking, was to completely remove a wall-sized, well-insulated, triple-paned window from an adjacent concert hall. Can you say new information? Well, stream after stream of music with which I have had decades-long relationships was rendered as virtually new and unexplored. Imagine further, the window now removed, the tonal/timbral shadings of the music composed of a palette far more differentiated and real and natural than the muffled sounds that had formerly bled through the window (see digital technology, to date). It was as if the MU2 had adopted a palette of 152 crayons, if you will, compared to the 24 crayons that the other Streaming DACs or DAC Streamers had used to render the selfsame music. There is a marked difference in the MU2’s presentation that finds the music it renders in the closest sense to a master tape or Top-of-the-Line (TOTL) analog. And after hearing some of the priciest digital stacks, where you get so little for so much, I am afraid for their comparison to the Grimm Audio MU2, where you get so much for so little. Astounding!

Yet the MU2 not only commands your attention via its outstanding technical prowess, but it grabs your heart as well, with a profound and immersive musicality that will find your current reference digital front-ends dismissed entirely. Soon after, this reviewer contemplates what will need to move to accommodate this one-box assault on the state-of-the-art.

I had thought for a long time that what rendered outstanding transparency, resolution, and detail would render left-brain nirvana, while leaving the right brain emotionally comatose. The Grimm Audio MU2 brings a synergistic balance that provides nirvana all the way around, with nary a competitor in sight to date. I could classify the experience with the MU2 as a fundamental revelation of my music beyond the abilities of any other consumer musical format to date, and perhaps comparable to that of a master tape. I say this having had the opportunity to listen to vinyl rigs—turntable, tonearm, cartridge, phono preamp, step-up transformer—of well nigh $250k, and they were not the Grimm Audio MU2’s equal, even as it sat in my very modest reference system. They did not move or engage in the same way as the MU2. Bravo!

The Grimm MU2 DAC’s volumetric cube—its soundstage—completely engulfs the MU1’s soundstage regardless of the aligned DAC, and all DACs were exceptional until compared to the MU2. The soundstage positioning—where performers are on stage, the space between performers, relative depth of performers—of the MU2 is outstanding. The MU2 rendered the texture and ambiance and air of a given venue with a dimensionality and an in-room palpability that again no other combination of components could achieve. You will not come across its equal in this respect, and certainly not at its price point, or several times its price point.

Bass

Tight. Focused. Detailed. The Grimm Audio MU2 brings dimension and depth and weight and gravitas to the bass region that other components or component pairs can only hint at, distantly. With the MU2 there are the beginnings of a thunderous rumbling, where with others there is but a pale ghost of what should be. The difference, even in this respect, is absolutely stunning.

Charlie Haden and John Taylor’s Nightfall (Naim Records) is an exceptional recording and to date, I had believed that all that was there or within the streaming content had been made available to me. The Grimm Audio MU2, however, stepped in and I was proven immediately and substantively wrong. The first thing I hear, witness, is the extended transparency and resolution that the MU2 brings to the very first track—“Chairman Mao.” The MU2 across this track lays bare completely the space between the two men, their interaction, the intricate details of play, while introducing the two men, more palpably than ever, into this very listening room.

Midrange

The Grimm Audio MU2’s performance with regard to the human voice has also moved it past all comers, and decisively so. It is as if the MU2 is also in love with the human voice and seeks to make it flesh, or at least palpable and in-room when played back. Further, the MU2 provides a weight that extends across the frequency range, provides weight and gravitas to the midrange, and yet obscures nothing therein. In fact, it has no equal in revealing copious amounts of detail throughout that same frequency range. Hyperbole? One listen and you’ll get it.

Shirley Horn’s “Beautiful Love” (You Won’t Forget Me, Verve) is a favourite that I have literally used for decades to discern the abilities of all manner of components and speakers as I searched for my next component. In other words, I know it extremely well. As “Beautiful Love” plays Toots Thielemans’ harmonica always stage left, always holographic, now has weight and gravitas that fleshes out its holographic image, and its timbre and tone are more organic, more real. Shirley enters and that same weight and gravitas give her in-room standing. She is not now the disembodied voice, as her every word and word formation and breath are clearly, texturally and naturally rendered, full of emotion with not a wit of sibilance. Whether it was Joan Shelly or Sarah Jarosz or Andy Bey, the Grimm Audio MU2 handled their performances with aplomb and uniquely. Bravo!

Treble+

Dave Brubeck’s “Take Five” (Time Out, Columbia-Legacy) in three or four decades or more of listening has never sounded like this. I look over previous reviews in which I utilized this track and am taken aback. Yes, it’s all relative and they sounded good or great at the time, but in direct relation to what I am hearing now via the Grimm Audio MU2, all prior renderings absolutely pale in comparison, even those renderings of my highly vaunted electrostatic headphone rigs. Say it isn’t so.

“Take Five” cues in and it is transcendent. Joe Morello, drum kit, and cymbals—crash, ride, hi-hats—are texturally embodied in the confines of my listening room and they are shimmering something beautiful. The cymbals ride high, pristine, crystal clear. The timbre and tone of Paul Desmond’s saxophone is itself textured, rich, effusive. Eugene Wright and bass are no disembodied spirits haunting the distant background, there is no amorphous thump thump; instead, his bass is transparent, beautifully resolved, detailed, and tight.

WRAPPINGS, Design—Look, Feel

The Grimm Audio MU2, like its sibling, comes in a nondescript brown outer box that houses a nondescript brown inner box.

The Grimm Audio MU2 sits secured within the inner box via foam blocks and cutouts. The smaller inner box holds a stock power cord, a beautifully printed instruction manual, a flyer that encourages warranty extension, and a plug-in IR facilitator.

Again like its sibling, the MU2 shares the selfsame chassis as the MU1, which is designed in a simple, elegant, modern, and unassuming way. Instead of a bronze/gold wheel on its top surface, the MU2 has a grey wheel, which easily distinguishes between the two components.

The Grimm Audio MU2 brings an increased functionality to its svelte design that further helps to establish it in minimalistic high-end systems and environments.

FUNCTIONALITY

The Grimm Audio MU2 is truly plug and play. Connect the MU2 via ethernet cable to your network, connect the MU2 via RCA or XLR analog interconnects, plug in the power cord to IEC socket, and press the little white button, nicely hidden above the IEC socket. Then you’ll need to connect to Roon, which will see the MU2 immediately, enable it, and select a given zone. Now your MU2 is rumbling at the starting line to get going.

The Grimm Audio MU2, like the MU1, bears a front facade that is minimalist—a small, centered screen that plays host to numerous bits of information, the product’s abbreviated designation (MU1), and the company’s logotype, with a white indicator light that says awake or asleep, positioned directly above the I in the Grimm MU2.

The MU2’s side panels are likewise clean and completely barren of information, buttons, etc. The MU2’s top—concave and bifurcated—split in two—holds at its centre a large grey wheel that is both selector and when depressed, input device.

The MU2’s back panel features, from left to right, a small white on/off switch (top, easy not to see), beside it a remote input, and below them, an IEC receptacle. To the right are two single-ended connections—Analog Out and Analog In—and to the right of these connections are two balanced connections—Analog Out and Analog In. To their right are three digital inputs—AES/EBU, Coaxial RCA, and Toslink. And at the top far right, a USB input and below it, an ethernet input.

Given that the MU2 is a streaming DAC that eliminates the need for a DAC and connects directly to your preamp, integrated, or amplifier, it purposes minimalism. Additionally, the MU2 serves as a preamplifier that can drive one’s amplifier(s) directly, thus eliminating not only a DAC but also a preamplifier in the chain of playback. For those seeking a minimalist reference system, the MU2 may well represent that need.

To become expert at the grey wheel atop the MU2, you will need to become expert via experimentation or a good and thorough read of the included manual and the online software manual.

FEATURES/SPECIFICATIONS

GRIMM AUDIO MU2

Roon Core and Roon End Point integrated
ultra low clock jitter
FPGA based discrete Major DAC
all sample rates and formats supported
relay based analog volume control
digital AES, spdif and optical inputs
analog XLR and RCA inputs
analog XLR and RCA outputs
headphone output
fully capable preamplifier
web control of setup via any browser
infrared remote control
external USB and NAS storage, optional internal SSD
Tidal and Qobuz support
355 x 85 x 295mm (WxHxD)
5 year limited warranty

Conclusion

The Grimm Audio MU2 as a complete streaming DAC is unparalleled in its ability to render one’s music in a way that is technically superb, while bringing unquestioned musicality that rivals some of the best and most expensive analog rigs. A short while ago I doubted, seriously, that streaming rigs would ever surpass CDs in their current technological form, let alone vinyl, only to be confronted with the daunting abilities of the Grimm Audio MU2 Streaming DAC. Well, I now eat those words and in a relatively short time frame, given the advent of vinyl, then CDs, and now streaming. The proof of that will be in your comparative listening sessions. I’ve done mine.

Suffice to say that in-house Streamer and DAC combinations at nearly twice the price of the Grimm Audio MU2 could not/did not compete. And this was clear the exact minute that the MU2, again just off a FedEx “freezer truck” and placed in the reference system, went unabashedly to the head of the class. It was not subtle—its rendering and playback abilities as compared to everything else (and there were very expensive DACs in-house for review, each alone more expensive than the MU2).

This one-box epiphany called the Grimm Audio MU2, in this reviewer’s opinion will move all systems, into which it is configured to the front of the streaming/rendering/playback class. It is as simple as that, and it’s a family trait, as the MU1 had easily dismissed streamers at more than twice its price. What Eelco Grimm and company have managed to do with the Grimm Audio MU2 is profound in the extreme, and I believe it will win many a convert, as the truth of what I’ve written above will be easily discerned in the listening. And it won’t take long to make that determination.

The Grimm Audio MU2 is a breakaway DIAMOND AWARD WINNER and a BREAKTHROUGH product as well. It will no doubt amass additional awards as the November Best of The Year 2024 issue makes its debut. No doubt. Bravo!

Pros: Unparalleled performance and able to surpass component combinations at twice its price and dare I say far above that. It is a streamer, a DAC, a preamplifier, and a Roon core of cutting-edge abilities.

Cons: You’ll need to read the instructions for a full understanding of its abilities.

The Company

GRIMM AUDIO BV

Grimm Audio MU2 Streaming DAC ($17,500)
info@grimmaudio.com
grimmaudio.com

GRIMM AUDIO MU2 STREAMING/DAC/PREAMP - REVIEW