Integrated Amp Reviews

The bottom line: The Krell has a slight edge in deep bass, dynamics, and capturing the forward edge of transients—the initial whack of a drum, the pluck of a string, the sss of a sibilant—while the Moon had a slight edge in getting the tonal colors of an instrument or ensemble, the flow of a rhythm, and a seamlessness across the audioband, from bass to midrange to airiest highs. A crude and perhaps overdramatic way of summarizing it: The Krell is a bit more lively, the Moon a bit more lifelike.

Notice my qualifiers: "a slight edge" in this or that, "a bit more" lively or lifelike. The Moon is also quite lively, and the Krell is also quite lifelike; I'm talking differences of degree, not of kind, and just a few degrees at that. It's not that the 700i is warm but not fast, or that the Krell is fast but not warm (like the difference, a few decades ago, between tubes and transistors); both are warm and fast. In most respects, their sonic signatures are remarkably similar. And where those signatures diverge, it's usually to achieve the same musical ends along slightly differing paths.

Take, for instance, the first track of trumpeter Dave Douglas's Charms of the Night Sky (CD, Winter & Winter 910 015-2), when Douglas and violinist Mark Feldman, both at center stage, play the melody in unison. With the Krell, I could tell them apart because I heard Douglas's mouthpiece and Feldman's bowing. With the Moon, those initial transient attacks weren't quite as clear, but I could still tell the two instruments apart by their distinctive harmonic overtones and the way that brass vibrations sound different from wood vibrations. And, I should point out, the Moon also let me hear more of Feldman's control of his violin, his subtle alterations of tone and phrasing. (And when he opens up, boy, does it sound silky!)

Similarly, I wrote in my review of the Krell FBI that, listening to Miles Davis's Cookin' (SACD, Analogue Productions LAPJ 7094 SA), when the band breaks into a faster tempo in "My Funny Valentine," I could hear Philly Joe Jones let up on the hi-hat cymbal after tapping it with his stick, an effect that added an extra layer of rhythm and cool that I hadn't noticed the previous hundred or so times I'd heard this album through other amps. With the Simaudio 700i, I didn't hear (not as clearly, anyway) the sudden release of the hi-hat—the forward edge of that very subtle transient—but I did hear, very clearly, the cymbal's change in volume and tonality, which produced the same rhythmic effect, if a bit less pronouncedly.

Another example: During Frank Kimbrough's opening piano solo in track 1 of the Maria Schneider Jazz Orchestra's Sky Blue (CD, ArtistShare AS0065), I could hear the keys hit the soundboard through the Krell—a nice you-are-there touch. The Simaudio 700i didn't let me hear that contact so clearly, but I got a slightly fuller sense of the entire piano's sound: its tonal colors, its harmonic bloom, even its size.

Not all the tradeoffs were compensatory. In "Nuages," track 1 of James Carter's tribute to Django Reinhardt, Chasin' the Gypsy (CD, Atlantic 83304-2), there are lots of percussive sounds bursting in the background—bells, triangles, woodblocks, as well as the trapset and a big bass drum. I could hear all of it with both amps, but only with the Krell could I clearly hear the counter-rhythm quietly tapped out (the forward edges of those transients again) on the triangle. Only the Krell could fully capture the hair-raisingly fast guitar fingerwork in Andy Irvine/Paul Brady (CD, Green Linnet GLCD3006). And in Michael Tilson Thomas's rendering of Mahler's Symphony 9 (2 SACD/CDs, San Francisco Symphony Orchestra 821936-0007-2), only the Krell unleashed the first movement's crescendo with utter effortlessness (due perhaps to its 300Wpc, compared with the Moon's 175Wpc)—though I wouldn't at all describe the 700i's effort as "strained." Compared with other amps in its power class that I've heard, the Moon sounded full-blooded. In fact, it sounded more dynamic—seemed to have more capacious reserves of power—than its rating might suggest.

One way to sum up this exercise: If you like listening to music from a front-row seat, preferably right up against the instruments, the Krell FBI is your integrated amp; if you don't mind sitting a few rows back—not the rear balcony, just a few rows from the stage—and if you value overall balance over zest (though without losing zest), then you might prefer the Moon 700i. You'd probably be very happy with either; again, I'm talking differences on the margin.

In other respects, the Moon gave me no grounds for complaint or reservation, either on its own terms or compared with something else. I've spoken already of its tonal colors, its harmonic integrity, its rhythmic sway, its balance and extension across the octaves, but I want to elaborate a bit on that last point. In my A/B listening, the Krell had the edge in the bass, but the Simaudio was hardly bass-shy. In "Mood Indigo," from Masterpieces from Ellington, a stunning DSD remastering of the Duke's very first LP, recorded in 1950 (CD, Columbia/Legacy CK 87143), Wendell Marshall's rubato bass line was clarion clear, replete with the pluck and, even more, the ensuing wood vibration—such a cool, casual cadence. In the London Sinfonietta's recording of Górecki's Symphony 3 (CD, Elektra/Nonesuch 79282-2), conducted by David Zinman, the contrapuntal bass lines about three minutes into the first movement—which I'd never heard until plugging in the Krell FBI a few years ago—were no less audible. Ditto the deep bass line under the funky bass line that opens the title track of Donald Fagen's Morph the Cat (CD, Reprise 49975-2; 2 LPs, Reprise 49975-1).

As for the very high frequencies, the fizzy harmonics of the guitar strums in "Tangled Up in Blue," from Bob Dylan's Blood on the Tracks (SACD/CD, Columbia CH 90323); the stadium ambience throughout Miles Davis's posthumous Live Around the World (CD, Warner Bros. 46032-2; or, better yet, the 2 LPs of Warner Bros. 9362-46032-1), especially in "Human Nature"; the natural reverberation of the concert hall in any well-recorded classical release—in every case, the recording space, the air around the musicians, filled the rear of my living room from wall to wall, up to the ceiling, and out the window into the street.

Speaking of spatial matters: The soundstage was as wide and deep as the recording and the rest of the system allowed. Imaging was tightly focused but not Etch-a-Sketch-y, which is to say that voices and instruments had a rounded palpability; they didn't simply emit the sounds that the musicians were playing and singing, they radiated them.

More to the point, no single aspect of the music drew untoward attention to itself. To a degree that has been rarer in my 25 years of reviewing than you might think (though it also happened while listening to such exceptional speakers as the Verity Audio Sarastro IIs or, currently, the Revel Ultima Studio2s), I found myself drawn deeper into the music, reacting to a particularly awesome passage not by thinking "Wow, listen to how 3D that trumpet is!" but rather "Wow, listen to how great that trumpeter is!" This, I think, is the hallmark of a high-end component that you can live with over the long haul, after you've grown accustomed to any initially thrilling novelties of its sound.

Conclusion
Each of us, even the most seasoned reviewer, has listening biases; that's why, occasionally, we explicitly point them out. But what usually goes unrecognized is that these biases are often a product of the equipment we've heard, liked, and bought over the years. At some point, you hear a terrific amp (or pair of speakers, or whatever) that's especially brilliant at, say, capturing fast transients or painting a precise image. You conclude that you prefer gear that does those things, and you tend to sniff a bit at gear that doesn't. Once in a while, you come across a component that doesn't quite meet the highest standard of that particular trait but comes close, while setting new standards (at least compared with other gear you've heard) for traits that you value highly but have taken pretty much for granted until now.

That's what happened with me and Simaudio's Moon Evolution 700i. Will I toss aside the Krell FBI and install the 700i full-time instead? I don't know; I'm still a bit up in the air about that. The fact that I'm even considering such a step is significant; it's a sound of surprise.