In 1993, Rotel released the first three models in what became their critically acclaimed Michi line of electronics: the RHB-10 power amplifier, the RHC-10 passive controller, and the RHQ-10 equalizer. Rotel claimed that the Michis represented the very best they then had to offer in terms of design, technology, and sound quality. Over the next few years Rotel released five more Michi models, including a smaller power amplifier (RHB-5), an active preamplifier (RHA-10), an FM tuner (RHT-10), and a mammoth CD player (RHCD-10). The Michis were easily identified by their deep-gray cases of heavy-gauge steel, complemented by meticulously finished side panels of Japanese redwood -- but it was the many progressive technologies implemented in each that made them special.
Although the Michi line was discontinued in late 1999, Rotel’s chief technical officer, Daren Orth, told me that much of what made the Michis special made its way into Rotel’s 10 line, launched just weeks after the Michis were discontinued. Some Michi DNA even made its way into Rotel’s 15 series, which debuted in the 2010s. This year, in honor of the company’s 60th anniversary, Rotel has brought the Michis back.
Michi 2.0
As in the launch of the original Michis in 1993, the resuscitated line was brought to market with three “flagship” (their word) models: the S5 stereo amplifier ($6999, all prices USD), the P5 control amplifier ($3999), and the subject of this review, the M8 monoblock amplifier ($13,998/pair). The X5 and X3 integrated amplifiers ($6999 and $4999, respectively) were added just recently, for a total of five Michi models. At 130.3 pounds each, the Michi M8 is by far the heaviest, densest amplifier I’ve reviewed, with the exception of Simaudio’s colossal Moon 888. Each M8 comes entombed in a heavy-duty carton of quad-corrugated, double-fluted cardboard. Having removed the outer box, I was greeted by a small Michi poster and an owner’s manual, these laid atop a large piece of Styrofoam surrounded by more double-fluted cardboard. Below the foam was the M8, sheathed in a velvet-like cloak. On its right flank was a box containing a sleek aluminum remote control, a USB key, batteries, and an Allen key. On the left was a larger box containing two pairs of gloves, a heavy-duty 15A power cord, a spare fuse, and trigger and Ethernet cables. I was surprised by the second pair of gloves -- until I saw the two ideally placed cutouts to each side of the amplifier.
Each Michi M8 measures 19”W x 9.375”H x 18.25”D. Resting on my personal pair of 1”-thick solid wood amp stands, they displayed a quality of fit and finish well beyond anything else Rotel has ever produced. The 4.5mm-thick top plate and 4mm-thick bottom, front, and rear panels are all made of extruded aluminum finished in matte black -- the only color available across the Michi line. The heatsinks of 1”-thick extruded aluminum covering each side panel are also matte black, but textured differently for a bit of contrast. The front panel is covered with a single piece of 2mm-thick glass. When the M8 is powered down, this sleek, minimalist faceplate shows only the Michi logo etched at top center, and an illuminated standby button at bottom center. Press this button and a small, recessed, high-resolution TFT display lights up dead center on the faceplate. This little screen indicates the menu items accessible using the remote-control handset, which can be used to operate all Michi models. It can be used to toggle the M8 between Standby and On, set up the network, restore the M8’s factory defaults, configure Auto Power Off, update the M8’s firmware, set the screen to one of five levels of brightness, and configure it to function as a Peak Power Meter or a Frequency Spectrum Analyzer at varying levels of resolution.
The rear panel is dominated by two large, ultraquiet, thermostat-controlled cooling fans, one each at far left and right. No matter how long or loud I played the M8s in three months of listening, I never got them hot enough to activate their fans.
Between the fans are five recessed bays. In the first, at top center, are an Ethernet jack, an RS-232 control port, a balanced/unbalanced rocker switch, and 12V input and output jacks. Centered below this is the second bay: single balanced (XLR) and unbalanced (RCA) input jacks. The three remaining bays are at bottom: at center, the fuse bay, power rocker, and a 15A IEC inlet for the power cord; and at right and left, for the speaker cables, pairs of five-way binding posts of rhodium-plated copper.
As for what’s under the M8’s hood, Daren Orth revealed only what Rotel permitted him to tell me: Three teams of engineers were involved in the design of the M8 and the S5 stereo power amp. The power supply, designed by a team at Rotel’s factory, uses twin, factory-wound 1200VA toroidal transformers, each contained in an epoxy-filled enclosure. There are independent voltage regulators and taps from the transformer to isolate power to the circuits, high-current rectifiers for the amplifier circuits, and a bank of four slit-foil, high-efficiency, low-ESR, bulk storage capacitors capable of storing 188,000µF. The differential class-AB amplification circuitry includes custom circuit boards made of a proprietary blend of CEM2 and FR4 (a specialized cement mixed with a glass-reinforced epoxy laminate material), solid copper traces, shielded low-gauge wire made of ultra-high-grade oxygen-free copper (OFC), and a series of 32 Sanken MP1526 and MN1526 transistors.
Throughout the designing of the M8 and S5, a team of acoustic engineers based in Rotel’s UK office scrutinized the parts selection -- resistors, capacitors, output devices, transistors, input and output connectors -- to perfect the models’ acoustic tunings. An independent UK company was tasked with the visual design of all five Michi models, as well as the design of multiple vibration-isolating strategies such as the Michis’ uniquely damped feet, robust steel chassis, panel connections, and the independently enclosed transformers used throughout the Michi line. This company also sourced the TFT display used in the M8 and S5, as well as designing the GUIs of the M8, S5, and P5 preamplifier, and the Michi remote.
But masterful design means nothing without precision execution. Every part used in each Michi model, including the mechanical, the electrical, even the packaging, must pass Rotel’s rigorous internal quality control (IQC) inspection. Manufacturing of the circuit boards is tightly managed by Rotel’s in-house surface-mount technology (SMT) equipment and through-hole (DIP) insertion processes to ensure that all components and assemblies meet strict QC requirements.
Each PCB is individually inspected in proprietary testing jigs. Products are then tested again during the assembly process at multiple stations, including full Audio Precision automated testing and active listening. Each unit then passes through a multi-hour burn-in process, then is fully tested again, including listening, before being packaged for shipping.
A completed and fully tested Michi M8 is specified to produce 1080W into 8 ohms or 1800W into 4 ohms, with total harmonic distortion (THD) of 0.018%, intermodulation distortion of 0.03%, and a signal/noise ratio of 120dB. With a damping factor of 200, the M8 will provide a firm grip on pretty much any speaker thrown at it; and with gains of 30dB (balanced) or 34dB (unbalanced), rest assured that it should never sound shy, even when paired with a low-gain preamp.
Setup
Setting up two 130-pound amps went about as easily as one can expect. I began by leaving enough space between the Michi M8s for my reference Simaudio Moon Evolution W-7M monoblocks, so that I could easily swap speaker cables for A/B comparisons. My Audio Research Reference 6 preamplifier, PS Audio DirectStream DAC, Paradigm Persona 7F speakers, and Torus AVR 20 power conditioner all remained in place, connected with Kimber Kable speaker cables and balanced interconnects, Analysis Plus digital links, and Clarus Crimson power cords.
Power and finesse
I began my listening with a single from 1993: Willie Nelson and Sinéad O’Connor’s cover of Peter Gabriel’s “Don’t Give Up,” later released on Nelson’s Across the Borderline (16-bit/44.1kHz FLAC, Columbia). From Nelson’s opening picks on acoustic guitar, the M8s presented as sounding a bit thin. After listening to this track a few times, I realized that that description was incorrect -- compared to what I’m used to from this track, what I now heard was a vaster soundstage, a cleaner reproduction of microdetails, and an almost indulgent amount of air around instruments. The overall effect was a unique combination of fast-sounding stringed instruments, sharp transients, and articulately defined inner details. I could effortlessly hear wisps of air under Nelson’s and O’Connor’s singing, and was awestruck by how precise yet delicate the cymbal sounded as Jim Keltner gently peppers it with taps off to the right. Nelson’s and O’Connor’s voices were chiseled out at center stage with enough spatial acuity to suggest that O’Connor was singing directly opposed to Nelson on the same plane, and very close to the microphone. There was no hint of overhang or echo to either voice, and the M8s wonderfully communicated the juxtaposition of the singers’ speed and nimbleness with the slow, gentle decays of Nelson’s delicately picked strings. Subtle shifts in vocal dynamics were immediately apparent, easy to follow, and nicely balanced with the rich, melodic-sounding electric guitar floating about 2’ to the right of my right speaker. I could also hear a refreshing amount of texture in each note of Don Was’s bass guitar at right center, even with several other instruments being played.
The M8s’ wonderful layering of voices and instruments on stage, complemented by a genuine sense of inner detail, prompted me to listen to “Don’t Give Up” many times. Unfortunately, that scrutiny laid bare something else: bass notes, though effortlessly penetrating the mix, didn’t have as much weight as I would have liked. Clearly, further listening was required. I then concentrated on the instrumental version of the song, originally released as the single’s B side. Here, drum thwacks sounded punchy -- surprising, considering the lack of bass oomph heard earlier -- and I quite enjoyed the duration of their decays. Paulinho da Costa’s struck triangle shone through clear as day without sounding stark, and the M8s made it easy to sense the emotion behind Mark Isham’s expertly muted trumpet.
To pinpoint what I wasn’t hearing from the M8s in terms of bass authority, I cued up “Thanks to You,” from Boz Scaggs’s Dig (16/44.1 FLAC, Virgin), hit Repeat, and listened for a while, each time focusing on a different aspect of the bass. At first I struggled to isolate what was catching me off guard -- the M8s displayed impressive levels of depth, texture, detail, tonality, and punch, but still some tiny thing seemed to be missing. I discovered the cause almost by mistake, and wouldn’t have discovered it at all had I not compared the Michi M8s side by side with my reference Simaudio Moon Evolution W-7Ms ($25,000/pair, discontinued): a slight discontinuity in the fulsomeness of bass notes relative to the volume setting.
At lower levels -- anything below about 80dB -- bass notes through the M8s lacked a bit of weight and sounded a wisp recessed. As I increased the volume from “20” to “25” on my ARC Reference 6 preamplifier, the fullness of body of bass notes bloomed, sounding very close to but still not quite as full-bodied as through my W-7Ms. At a volume of “35,” or about 95dB, the M8s seemed to hit their stride: bass across the board was now on a par with the bass of my Simaudios, and got only better as I wicked up the volume, reminding me a lot of what I heard during the listening for my reviews of McIntosh Laboratory’s MC1.25kW and Simaudio’s Moon 888 monoblocks. Moreover, as did the big Macs and the big Moon 888s, the Michi M8s had an uncanny ability to maintain consistent tonality when pushed hard -- there was no shift toward brightness, which I can’t claim for the Simaudio W-7Ms. Perhaps there’s something to be said for having more than 1kW of power on tap.
Back to the Michi M8s. I pressed Play for “Riders on the Storm,” from the Doors’ L.A. Woman (24/88.2 FLAC, Elektra), and listened to this 7:08 track in its entirety before putting it under my aural microscope. From the first seconds, the M8s showcased their deft ability to conjure up a holistic soundscape packed with sonic detail and atmosphere. The rain fell well beyond the cabinets of my Persona 7Fs, and the thunder rolled high and wide across the entire soundstage. Not long after Ray Manzarek’s Fender Rhodes electric piano emerges at left, in tandem with John Densmore’s tapped cymbal at right, Jim Morrison’s voice enters, overshadowing Jerry Scheff’s electric bass. Both are at the center of the mix, Morrison seemingly positioned about 5’ in the foreground, Scheff about 6’ behind him. Each of the song’s 428 seconds contains an abundance of subtle nuance, inflection, and ear-tugging detail -- from 00:00 to 07:08, the Michi M8s did nothing to prevent my hearing every one of them.
Head to head
So far, the Rotel Michi M8s had governed my Paradigm Persona 7F speakers without showing a hint of mercy, and sounding damn fine while doing so. I didn’t have another $13,998 pair of monoblocks on hand to put up against the M8s, but after listening to them for several weeks, I’m not sure I would have wanted to. On paper, the Michi M8 far exceeds what my Simaudio W-7M ever promised to deliver in terms of power -- and for $11,002/pair less. As for build quality, I’m inspired by what Rotel has been able to bring to market for $6999 apiece. The materials are top notch, and the ultratight panel joins are reminiscent of those I saw in EMM Labs’ DV2 D/A converter. The Michi M8s’ fit, finish, and features easily match those of my W-7Ms, and exceed those of any other amplifier I can think of at this price.
Minor differences in bass reproduction aside, the Michi M8s’ sound had more in common with that of my W-7Ms than I’d anticipated. Overall, the Rotels produced a bit more air around instruments and voices than did the Simaudios, despite the latter sounding a bit cooler, denser, and more vibrant. Both pairs of amps communicated tonal colors convincingly well, projected wide and deep soundstages, and projected images of voices and instruments far beyond the confines of my speakers’ cabinets. Both sets of monoblocks also sounded effortlessly dynamic and uncompressed at all volumes I dared to try, though the Rotels did seem to maintain their balance and composure a bit better when pushed beyond comfortable listening levels. However, the Simaudios had the advantage in aural imaging, consistently drawing those images with more solidity and razor-sharp outlines. The Michi M8s painted more of a holographic, faintly diffuse-sounding overall picture. And when I put ear to tweeter, the Simaudios were quieter at idle -- but that ear had to almost touch that tweeter before I could hear anything from either pair of amps. Call it a draw.
Conclusion
I enjoyed my time with Rotel’s Michi M8 monoblocks -- and that is a huge understatement. The Michi M8 has redefined what I can expect of a monoblock power amp costing $13,998/pair. Its build quality is astounding, its power was beguiling, and its ergonomics, GUI, and multiple display options functioned perfectly and were a breeze to use and read. In terms of sound quality, Rotel’s Michi M8 is a triumph. Sure, there were a couple of minor misses in comparison to my reference monoblocks -- but when you take into account that my Simaudios cost nearly twice the price, those misses dissipate entirely. The Michi M8 is a steal. It has reminded me that there are still companies out there that consistently try hard to push the boundaries of what they’re capable of while ever increasing the ratio of performance to cost. Highly recommended!
. . . Aron Garrecht
arong@soundstagenetwork.com
Associated Equipment
- Speakers -- Paradigm Persona 7F
- Subwoofer -- JL Audio Fathom f112 (2)
- Amplifiers -- Simaudio Moon Evolution W-7M (monoblocks), Parasound Halo A 51 (five-channel)
- Preamplifiers -- Anthem AVM 60, Audio Research Reference 6
- Digital-to-analog converter -- PS Audio DirectStream
- Sources -- Oppo Digital UDP-203 universal BD player; Intel NUC computer running Windows 10, Roon
- Interconnects -- Analysis Plus (USB), Clarus Crimson (S/PDIF), Kimber Kable Select KS-1116 (balanced)
- Speaker cables -- Kimber Kable Select KS-6063
- Power cords -- Clarus Crimson
- Power conditioner -- Torus AVR 20
Rotel Michi M8 Mono Amplifiers
Price: $13,998 USD per pair.
Warranty: Five years parts and labor.
Rotel America
6655 Wedgwood Road North, Suite 115
Maple Grove, Minnesota USA 55311
Phone: (510) 843-4500
Website: www.rotel.com
