Simaudio Moon Evolution i-7 integrated amplifier
I was the member of the family on whom the others could depend for technical assistance: mending eyeglass frames, fixing the radio, replacing the lightbulb in the oven, getting the car to idle smoothly. No job too big or too small. House calls a specialty.
That began to change when the world became more dependent on consumer electronics—except for perfectionist audio, of course—and as consumer electronics became more and more dependent on microprocessors. "How do I reset the time on my VCR?" I don't know. "How do I turn off the flash on my camera?" I don't know. "Where are all the songs I downloaded last night?" I don't know.
Slowly but surely, it dawned on my family that I'm an idiot, for the simple reason that I no longer seem to know very much. I chafed at that conclusion, for the simple reason that I shouldn't be expected to know what I can't be expected to know—at least until I've had a chance to read the instructions.
I retreated to my little world of belt-driven record players and loudspeakers stuffed with jute: things I know about. But the world came knocking again, anxious to show what a fraud I really am. There it was, in black and white, on p.8 of the owner's manual that arrived with the Simaudio Moon Evolution i-7 ($6000), which has replaced the Moon i-5 as the Canadian manufacturer's top integrated amplifier: "The Moon i-7 integrated amplifier includes powerful software..."
Uh-oh.
"What follows are step-by-step examples of how to configure an input..."
I felt like a small, frightened woodland animal. But my fears proved ill-founded: The instructions were clear and easy to follow. Within 15 minutes, I'd given every one of the inputs a custom label, some of which were childishly amusing.
It wasn't hard at all. So I carried on...
Description
The Moon Evolution i-7 is one of Simaudio's statement products: a good-looking, surprisingly heavy (58 lbs), solid-state integrated amplifier built into an aluminum alloy chassis more or less equal in size to that of the SuperNova CD player, which Wes Phillips wrote about in the January 2007 Stereophile. The i-7 comes with a nice-looking remote handset, built into a molar-shaped alloy enclosure so heavy that, when I accidentally dropped it, it dented the floor. Seriously.
The i-7 is fully balanced, although the single-ended inputs outnumber their balanced counterpart four to one. There's also a tape loop, a pair of auxiliary line-level outputs (their output impedance is a low 50 ohms), special jacks for communicating with other Simaudio products, and a nine-pin RS-232 port: something else I don't know much about.
The front side of the Moon is a marvel of beauty and usefulness. Scattered around a red-lit display are the soft-touch buttons needed to run the amplifier's various setup routines, as well as switches for the monitor loop, mute, standby mode, display lighting, and two buttons for toggling back and forth among the five line-level inputs.
A large knob off to the right actuates an optical encoder, which itself selects among many combinations of metal-film resistors for signal attenuation. (The knob is also used as a selector switch during the setup routine.) This is Simaudio's M-eVol, a resistive-array circuit with 130 discrete steps, intended to avoid the distortions associated with old-fashioned potentiometers. The M-eVol system is also speed-sensitive, which is something no potentiometer can match: In the lowest portion of its overall range, from 0dB to 30dB, loudness is adjusted in 1dB steps; above that, the speed with which the knob is turned determines whether loudness is to be adjusted in steps of 0.5dB (slow turning) or 1dB (quick turning). Incidentally, the mute control works not by clamping input signal to ground, but by instantly switching the M-eVol system to zero—from whence it can, of course, be switched immediately back to the previous setting.
The Moon i-7 lacks a mono-blend or channel-reversal switch. Side-to-side balance is adjustable, but only from the remote—which makes more sense than doing it while standing next to the amp itself, I suppose. In any event, the user can adjust the left-to-right loudness differential in accordance with a hundred small steps; that was certainly enough for me.
To look inside the Moon's well-made chassis was to conclude that the i-7 is in fact a monumentally well-designed, high-tech power supply, with a nice integrated amp along for the ride. From the two wildly overspecified toroidal transformers forward, every bit of the power supply is discretely dual-mono. (Actually, the power supply for the logic circuitry isn't dual-mono, but then, I've always suspected that logic comes only in mono.) Everything looked stiff but sensible, and my search for a flaw in the layout—some weakness that might leave the power supply open to hum, or create ground points of differing potential—was as fruitless as playing chess with a master: Someone else had already thought of everything.
The audio circuitry is also dual-mono, built with a combination of discrete transistors and integrated circuits. The i-7 is a fully balanced differential design from input to output, and, in the interest of banishing timing distortions, does not use global feedback—a philosophy that Simaudio refers to as their Lynx technology. The i-7's preamp section operates in class-A, and the power amp operates in class-A up to 5Wpc, beyond which it works in class-AB.
Installation
Getting the Moon up and running was as straightforward as one could expect from an amp that weighs more than a nine-year-old girl. The user can, of course, simply plug the thing in straight out of the box, ignore the software setup routine, and play music—in which case the inputs remain unlabeled (apart from "B1," "S1," and so forth), and likewise remain unadjusted for volume "offset," which can be done later—with ease—to compensate for differences among various source components.
But straight out of the box, the i-7 didn't sound its best. During my first several days of listening, the Moon underwent the most noticeable changes I've ever heard from a solid-state amplifier—all of them for the better.
The Moon i-7 is shipped with a nondescript AC power cable, which I relied on for most of my listening. (I noted a small sonic improvement when I tried aftermarket cords from Cardas and JPS.) Spiked feet are also included, and those absolutely must be threaded into place—not so much for any sonic improvement (I heard none), but because the heavy amp has no feet at all without them, and the various edges, corners, and bolt heads on the bottom of its chassis can scratch finished surfaces. Simaudio supplies dimpled pucks for use with the spikes, thus eliminating at least one cosmetic concern.
Listening
After running in the Moon Evolution i-7 for a number of weeks, I sat down to some serious listening and was impressed from the start by the amp's clarity and apparent lack of coloration. Another four weeks later, I still can't detect much in the way of an obvious i-7 character. That in itself will be recommendation enough for some.
The i-7 had the requisite neutrality to allow the strings and woodwinds of Trevor Pinnock's English Concert to sound timbrally convincing in the group's live recording of Handel's Tamerlano, from 2002 (CD, Avie AV0001), and was sufficiently clean and transparent to preserve the spatial distinctions between soloists and continuo. Nearer the other end of the opera timeline, the Simaudio amp did a fine job with the famous Rudolf Kempe recording of Wagner's Lohengrin: It sailed through the many dramatic peaks ("Heil dir, O Tugendreiche!") without making the louder voices sound strained, and the Moon reproduced the sound of a modern orchestra with what I felt was just the right amount of bass weight—and not a shade more than was called for. Timpani, in particular, had fine heft, even when played subtly. I heard nothing in the way of added crispness or brightness, although I wouldn't have wanted the cymbals to sound any drier than they did.
The i-7 also used its clarity and cleanness to good effect on rock recordings. It uncovered layers of detail in the somewhat dense and overly reverberant soundfield of the Byrds' Sweetheart of the Rodeo (CD, Columbia CK 65150), in addition to which it was a great amp for helping to decipher otherwise murky lyrics. More important, the Moon i-7 was sufficiently free from those distortions that keep lesser amps from even suggesting the musical qualities of rhythm, pacing, and momentum. With the Simaudio amp at its heart, my system leaned into Roger McGuinn's opening bars on the Byrds' "Lover of the Bayou," from Untitled (CD, Mobile Fidelity UDCD 722). Swingier numbers—such as Django Reinhardt's crazy "Mystery Pacific," from a reissue of The Art of Django (CD, Beat Goes On BGOCD198), and Thelonious Monk's "Off Minor," from Monk's Music (LP, Riverside RLP-242)— never failed to involve me on a physical level.
One of the most obvious sonic distinctions between the Moon i-7 and the generally low-powered tube amplifiers I usually enjoy was a difference in spatial perspective. Listening to the Moon i-7, I found the "stage" significantly wider than I'm used to hearing—singers and players now stretched all the way from left of the left speaker to right of the right. At first I also thought that the Moon i-7 was lacking in spatial depth, but that proved untrue: That was merely what I expected to hear when first struck by the increase in stage width.
The localization of players and singers, as well as the sense of wholeness and solidity of instrumental and vocal images, was very good with the Moon i-7. On my favorite contemporary bluegrass recordings, such as Blue Highway's Midnight Storm (CD, Rebel REB-CD-1746) and Del McCoury's wonderful Del and the Boys (CD, Ceili CEIL2006), the sounds of the instruments were neatly lined up, each occupying a definite chunk of sonic air: a technological illusion, I know, and one that has very little to do with the way things really sound in concert—but it's there on the records, it's fun to hear, and the i-7 did a fine job of bringing it to life, neither dulling nor exaggerating the pleasant effect.
Generally speaking, a powerful amplifier can confer an indescribable sense of confidence on some listening experiences, especially of good piano recordings—and the Moon i-7 did not disappoint. I enjoyed using it to play the very rich and lyrical Bach Prelude BWV 659 (arranged by Busoni), "Nun Komm' der Heiden Heiland," recorded in the 1970s by Chris Copping lookalike Mindru Katz (CD, Cembal d'amour CD112); and my perennial favorite, pianist Jorge Bolet's Rediscovered Liszt Recital (CD, RCA 63748-2), including his frenzied performance of the overture to Wagner's Tannhäuser (which I enjoy, although some friends think Liszt's arrangement is grotesque). In the latter example, my playback system was unperturbed by even the loudest chords, although the sound didn't have quite the richly textured decay I look forward to hearing from the instrument.
Apart from falling short on such things as the purr of a big piano, as described above, or the full harmonic complexity of the finest stringed instruments, the sonic presentation of the Moon i-7 was hard to fault. The i-7 could be exceeded more decisively—by amplifiers that are more expensive, less easy to use, or both—in the ability to convey a sense of flow and humanness from recorded music. If an audio amplifier exists as a sort of stencil for coaxing household electricity into a semblance of real music—and I suppose, in a sense, it does—then one must also acknowledge that most such things trace the music's outline in ways that lack nuance, and thus sound more mechanical than what they're trying to imitate. It's a rare amplifier that follows every curve sufficiently well to entirely fool the ear, and the i-7 doesn't make it to that level.
One last note: Not every solid-state amplifier can successfully drive the original Quad ESL electrostatic loudspeaker—especially not wide-bandwidth amps, which are flustered by the crazy dip in the ESL's impedance curve way up high. The Moon qualifies as a wide-bandwidth amp, yet it drove the Quads without complaint. In fact, the i-7 sounded better with the Quads than at least one otherwise lovely tube amplifier I've tried (itself a subject I'll return to in next month's "Listening"). The i-7 let the Quads sing with all the emotion they're known for, and kept their bass panels on a tight leash: The floor toms and electric bass in Lee Feldman's "Give Me My Money," from his brilliant I've Forgotten Everything (CD, Urban Myth UM-114-2), were tight'n'tuneful—much more so than when I listened to the same cut with my Quad II amps doing the honors—and the big bass drum in Michael Tilson Thomas's very nice recording of Mahler's Symphony 3 (SACD, San Francisco Symphony 821936-0003-2) never got out of control, although I suspect it wanted to.
Conclusions
As Fee Waybill of The Tubes sang on that group's eponymous debut: What do you want from life? A powerful amp that does no more or less than boost the signal it's given, for better or for worse? An amplifier that imbues all recorded music with an indefinable sense of artistic nuance and intensity? A meaningless love affair with a girl you just met tonight?
Simaudio's Moon Evolution i-7 is very good at one of those things.
Some reasonable comparisons: At $6000, the Moon i-7 is significantly more expensive than the Naim Nait 5i ($1425) and Cyrus 8vs ($1795), but offers more than both of those amps in terms of ergonomic refinements—not to mention sheer output power. The Moon is on a par with the best I've heard in terms of rhythm and pacing, yet offers a wider bandwidth. Various tubed integrated amps, ranging from the Primaluna Prologue One ($1195) to the curvaceous Viva Solista ($9900), offer a slightly better, more human sense of flow—not to mention extra personality, assuming that's what you want.
As an engineering accomplishment and objet d'art industriel, the Simaudio Moon Evolution i-7 is a success, and its price is a fair reflection of the effort required to make it real. It is also a safe buying recommendation for anyone who wants power, neutrality, and flexibility—and doesn't want to jump through hoops o' flame to get them. A lovely thing.
