Pré-amplificador Simaudio Moon Evolution 740P (via Stereophile)


By Fred Kaplan • Posted: Apr 22, 2015

Transparency is a trait we all value in a hi-fi rig, and it’s a concept I’ve long thought I understood. A system that tosses up the illusion of a clear, spacious soundstage, on which you can hear—almost see—all of the singers and/or instruments, from side to side and, especially, from front to way, way back: that’s the ticket. Still, although such transparency is a sign that you’ve entered the realm of fine sound, it’s not an absolute requirement. Tonal accuracy, dynamic range, a certain thereness that conveys the emotional heft or delicacy of music—those things come first. Without them, the most precisely delineated soundstage is like an architect’s sketch of an oil painting. But after listening to Simaudio’s Moon Evolution 740P preamplifier, I see that I’ve had it wrong all these decades. Those other aspects are still more important (I’ve been right about that), but I’d had only a partial understanding of transparency, because I’ve never before heard, at any length, a system that delivers the concept full-range. But now that I’ve heard it, I also realize that transparency isn’t a mere audiophile bonus; it enriches, even transforms, all of those other qualities—tonal accuracy, dynamic range, that thereness—that excite us when a great recording sounds so close to the real thing. But let us begin at the beginning.

Description and Design
Simaudio’s 740P ($9500) is a solid-state line-stage preamplifier with a dual-mono configuration and balanced differential audio circuitry—a culmination of the Quebecois company’s premier series, the Moon Evolution models, which itself is the latest chapter of their storied 35-year presence in high-end audio. Outwardly, the 740P resembles previous Moon Evolution models: the attractive, curved-edged design (available in all black, all silver, or a combination called 2-Tone); the ultrarigid aluminum case with sharp thumbscrew cones protruding from the bottoms of four triangular pillars, to reduce the effects of spurious vibrations. But there are new refinements, inside and out.

Most touted in the 740P’s manual is Simaudio’s fully discrete, four-stage, proprietary M-LoVo low-voltage regulator, said to produce “exceptionally fast, precise and stable DC voltage” that results in “a power supply with a virtually unmeasurable noise floor.” Also designed especially for the Evolution line is an Independent Inductive DC filter, which isolates all the electronic parts in the signal path that are fed DC power. The signal path is shortened, and its impedance lowered, thanks to a four-layer circuit board—two layers for the audio signals, one for the ground, one for the power supply—etched with tracings of pure copper. The power supply, which has five stages of DC voltage regulation and extensive choke filtering, is oversize so that, as the demand for current swells, the supply of voltage dips only slightly, making possible (the manual claims) effortless dynamic peaks with no change in the music’s detail, color, or character.

Simaudio’s M-eVOL2 volume control comprises 530 discrete steps of 0.1dB each, with a variation of less than 0.05dB between channels across the entire volume range. Each line input is “home-theater ready,” meaning that the volume control can be bypassed. A SimLink controller port allows for two-way communication with other Moon Evolution models. Oddly, I discovered that I could also use the remote control to stop, play, pause, and change tracks with my Krell Cipher SACD/CD player.


I did all of my listening through Revel’s Ultima Studio2 loudspeakers. LPs were spun on a VPI Classic turntable with JMW Memorial tonearm and an Ortofon Blue Cadenza cartridge, plugged into a Nagra BPS battery-powered phono preamp. Digital discs were loaded into the Krell Cipher. Cables (single-ended from the phono, balanced from the CD player) were all by Nirvana. For a power amp, I mainly used Simaudio’s Moon Evolution 860A (review in the works), occasionally switching to the power-amp section of their Moon Evolution 700iintegrated amp (which I’ve had in my system for some time). To isolate the 740P’s sound, I also plugged the 700i’s preamp section into the 860A. For another comparison, and for other reasons discussed below, I borrowed a Pass Laboratories XP-30 preamp and connected it to the 860A.

The 740P’s manual says that it needs 400 hours of playing time to break in fully; based on my experience, I second that advice. Simaudio also recommends keeping the 740P on at all times: Turn it off for three days, and it takes another three days to warm up again. The good news: If you turn it off for a week or a month, it also takes three days to warm back up.


In his review of the Pass Labs XP-30 line preamp in the April 2013 issue, John Atkinson concluded that that unit validated the notion that “the beating heart of an audio system is the preamplifier.” I cocked an eyebrow when I read that, but after spending a few months with the Moon Evolution 740P, I’m inclined to agree. It makes sense: the signal passed through the preamp is what is amplified and converted to acoustic waves; the preamp does its work at extremely low levels that, by themselves, are nearly inaudible; any noise it contributes will be hugely magnified further down the chain. As you may have noticed from my summary, nearly all of the technical features highlighted in the 740P’s manual are claimed to reduce vibrations, distortions, and noise of all kinds. Perhaps this accounts for the 740P’s transparency.

Whatever the cause, with every album and song I played, I found it hard to take notes. I just sat back—or leaned forward—and soaked in the music, sometimes with an idiotic smile on my face, even if I’d heard the record a hundred times before. Finally, I tried to analyze what was happening. My first scribbled note: “All the music is breathing forth at the same time.”

Six months ago, if I’d read that sentence in a review, I’d have shrugged and muttered, “Yeah, well, my system does that too.” I would have been wrong. My system—an assemblage of perfectly respectable high-end components—didn’t quite do that.

Take “Nuages,” from Chasin’ the Gypsy, James Carter’s tribute to Django Reinhardt (CD, Atlantic 83304-2). In many past reviews I’ve marveled at how some piece of gear captured the oomph of the bass drum, the clinging of the bells, the clang of the triangle, or the distinctive strumming of each guitar, one metal-strung, the other nylon. But until the 740P, I’d never heard all of these elements in tandem; I’d never heard, at least not continuously, the rhythm of the bells playing off the rhythm of the drums, or the accordion playing off the violin, or the guitars trading fours. I’d heard the sounds, but I’d been missing something vital about themusic.

What I’m describing might strike some as mere detail, and they’d be right. It is detail: detail that lives in the low-level signals, detail that most preamps (including many very good ones) smudge but that the 740P let shine through—and, in doing so, pumped blood into “the beating heart” (to riff on JA’s image) not only of my audio system but also of my music.

Or take “Like a Rolling Stone,” from Bob Dylan’s Highway 61 Revisited, either the SACD (Columbia CH 90342) or, still better, Mobile Fidelity Sound Lab’s set of two 45rpm LPs (Columbia/MFSL 2-422). I don’t know how many times I’ve heard this song, but I’d never heard so much of the piano in the mix, or the airy whoosh of the Hammond B-3 so distinctly, or—as a visiting friend, a Dylan fanatic but not an audiophile, commented after listening with me—the raw edge of so much anger in Dylan’s voice. But, as with Carter’s cover of Reinhardt’s “Nuages,” what I found most riveting was the band’s cohesion: all the music breathing forth at the same time.

I was particularly struck by how the 740P captured the sound of acoustic pianos. One reason pianos don’t sound convincing through most stereos (or from most recordings) is that there’s so much going on across the range of loudness and frequencies: the percussiveness of the pianist coaxing the keys and the hammers hitting the strings; the dynamic contrasts in the pressure and release of the pedals; the bouquet of overtones wafting into the air; the resonant vibrations of the piano itself; and the mingling of all these sounds together. To get all of this—and to make it all seem to be coming from the same object in space—demands a lot of a sound engineer and a stereo. A slight discontinuity in frequencies, a slight smearing of time or phase alignment, can mess it up. With the Simaudio 740P, I heard all of it, or at least all that the recording and the rest of my system could parse. I suspect that this, too, has something to do with Simaudio’s ways of keeping the low-level signals pure.

Or take Analogue Productions’ breathtaking reissue of Duke Ellington’s aptly titledMasterpieces by Ellington, either the SACD/CD (CAPJ-4418-SA) or, especially, the LP pressed by QRP (APJ-4418). Duke’s piano isn’t the sonic highlight of this demo-disc jaw-dropper recorded by Columbia in 1950, but I’d never heard it sound so much like a piano, all its elements (percussiveness, tone, overtones, resonances, etc.) emanating from one place at one time.

Speaking of Analogue Productions, on their 45rpm LP reissue of Ella Fitzgerald and Louis Armstrong’s wonderful Ella & Louis (AP-4003), I’d previously found the rhythm section undermiked; I’d had to strain to hear what the musicians were doing. The 740P whisked away the burlap: the rhythm section still seemed way back there, no question, but I heard every chord Oscar Peterson played (and his piano was all there), along with Buddy Rich’s every snare swipe and cymbal tap (and he hit them in rhythm: it turned out they’re an integral piece of the music).

Or listen to Don Pullen play “Resting on the Road,” from his final album, Sacred Common Ground (CD, Blue Note 7 32800 2). I’ve hauled out this track for many reviews, sometimes to take note of the flesh-inflected hand drum on the right, always to remark on how well the component in question gets Pullen’s keyboard virtuosity: his heartbreak hesitations, elbow rumblings, and fiery cross-octave scrambles. But, again, I’d never heard them so heartbreaking, physical, or fiery. At one point, as Pullen chopped through arpeggios the way a skilled chef chops onions, I thought that maybe the 740P wasn’t getting it quite right; I remembered this passage sounding louder or fiercer through other systems, including ones of which the 700i had been a part. But swapping out components and listening again, I realized that, with those other systems, I hadn’t clearly heard the notes and chords Pullen was playing; the passage may have seemed louder or fiercer because it was muddier. But in no way, with this or any other album, did the 740P ever sound too analytical; its clarity didn’t come at the sacrifice of musical warmth.

As I wrote at the beginning, transparency isn’t the most important trait in audio. But as I also wrote, transparency can enrich all that’s good about a component or a system (and, probably, exaggerate all that’s bad about it). In all other ways, the Moon Evolution 740P was terrific. Horns, woodwinds, drums, voices, guitars: all sounded as they should, in terms of tone, color, size, and dimension—or at least as much as a given recording allowed.

As for the 740P’s bass, how deep it will go will depend a lot on your speakers. As far down as my Revel Ultima Studio2s go—fairly far, if not to subterranean depths—the 740P conveyed the full character of bass instruments. I never heard mere rumble, as I had from the James Carter album with some earlier systems; the 740P let me know (as others had not) that Cyro Baptista’s bass drum, heard loud and solo at the start of “Nuages,” is banged—or, more often, caressed—throughout the song. On Jasmine, a lovely duet album by Keith Jarrett and Charlie Haden (CD, ECM 2165), Haden’s double bass sounded more present. Though not to the same degree, the sound of the double bass is as complex as the piano’s: the snap of the fingers, the pluck of the strings, the vibration of the wood. With the 740P I heard all of this in perfect alignment; it felt almost as if Haden had come back to life, or as if I’d traveled back in time to hear him.

But surely something must be wrong with the 740P—or, at least, not completely right?

Two things

First, in the April 2011 issue, I compared two high-priced, high-powered integrated amps:Simaudio’s Moon Evolution 700i and Krell’s FBI. The Krell was more adept at handling bass dynamics and the forward edge of transients: the whack of a drum, the pluck of a string, thesss of a sibilant. The Simaudio was more agile with the tonal colors of an ensemble or an instrument, the flow of a rhythm, the seamlessness of the audioband from bass through midrange through airiest highs. The Simaudio 740P had this same set of strengths, as well as . . . I won’t say weaknesses (that would exaggerate it to the point of falseness), but lesser strengths. The 740P was remarkably neutral, with a slight tilt toward warmth—which, if there has to be any sort of tilt (and there almost always does), is the tilt I prefer. But these are only general remarks; I no longer have the Krell FBI, so I couldn’t make direct comparisons. But I hasten to say that the 740P outperformed the 700i on all these fronts.

My second caveat concerns a question of absolutes. After listening to the 740P for a while, I reread JA’s review of the Pass Labs XP-30, which he described as something close to the proverbial ideal of a “straight wire with gain.” I’d begun to think the same might be true of the 740P, but before I indulged in superlatives, I needed an established world-beater, or something close to it, as a reference. So I borrowed JA’s review sample of the XP-30, let it warm up for several days (he’d long ago unplugged it), and listened carefully.

It sounded different—maybe leaner—or was I just getting used to it? After a couple weeks of listening, I concluded that the XP-30 was a bit better, and certainly more transparent, than the 740P. With the XP-30, the stage went farther back, there was a bit more air between instruments, and the elements of the sounds of complex instruments (eg, pianos, double basses) seemed a bit more cohesive (there seemed to be more elements, just as a higher-bit HDTV has a more comprehensive color palette). All of my observations here about the 740P’s see-through, hear-everything wonders? Add another 20% percent or so of clarity and luster for the Pass XP-30.


I didn’t listen to it long enough or closely enough to the Pass Labs XP-30 to make a definitive judgment on its sound quality. I’d borrowed it just to see if the Simaudio was the last word in transparency. Apparently not, it turned out. However, the 740P costs a lot less—$9500 vs the XP-30’s $16,500 and the Moon Evolution 740P definitely ranked high in the league of last words. It’s a league I’d never dwelled in for very long, and I’ll be sad to leave it when I send back the Simaudio Moon Evolution 740P—or should I check my bank balances, gulp hard, and make that: “. . . if I send it back”?