Solid State Power Amp Reviews

In the September 2005 issue (Vol.28 No.9), I reviewed Simaudio's first reference-quality power amplifier: the 1000W, 220-lb Moon Rock monoblock ($37,000/pair). At the time, the Rock was a dramatic departure for Simaudio, then primarily known as a maker of midpriced gear that was good for the money. I found a lot to like about the Rock, concluding that while it wasn't quite up to the standard of the best superamps of the time, it was very good—and, for Simaudio, an admirable first shot at the state of the art.

Since that time, Simaudio has launched and filled out its Moon Evolution line, in the process moving steadily upmarket. That Simaudio has taken that move seriously has been proven by such Moon Evolution models as the Andromeda CD player, the P-8 preamp, and the W-8 power amp, which have set new performance standards and won rave reviews. The Moon line kept growing and getting stronger, leaving only one thing missing: a big-time, big-power, big-money, big-everything reference power amplifier. And in January 2011, that void was filled by the . . .

Moon Evolution 880M
Unlike the Moon Rock, the product of a very short development cycle to service an urgent market niche, the Moon Evolution 880M was developed and refined over a period of years, according to Simaudio's Lionel Goodfield. "Don't get me wrong," he told me; "the Rocks were good amps in spite of the short development time . . . we've got really good engineers. But we spent years perfecting the 880Ms. They really show what we can do."

The 880M is based on principles and circuitry similar to those seen in Simaudio's smaller Moon Evolution amps, here scaled up to such numbers as: 32 output devices (Moon bipolar transistors custom-made to Simaudio's specs), 260,000µF of power-supply capacitance, maximum outputs of 80V and 100A, and, of course, power outputs of 800W into 8 ohms or 1600W into 4 ohms. The rest of the 880M's specs are equally impressive—including a shipping weight of 92 lbs. Each amp is packaged in a heavy-duty flight case, which makes handling and unpacking it much easier than having to power-lift it out of a deep cardboard box.

The 880M is a DC-coupled, fully balanced differential design, and its long incubation in R&D allowed Simaudio to develop and include several new technical features. The circuitry of each 880M begins with a massive power supply built on two 1.3kVA toroidal transformers, a proprietary design unique to Moon, and two banks of soda-can–sized capacitors. Then comes a proprietary combination of topography and components that Simaudio calls its Lynx Technology, whose key features include the absence of any global feedback, no input or output coupling capacitors, short circuit paths, and the creation of an optimal electromagnetic and physical environment for each component. For example, they use four-layer circuit boards with heavy traces of pure copper, not to assign certain functions to particular layers, but to minimize the length of the signal path and ensure that the two sides of the balanced circuit are identical.

The components themselves are custom-made to Simaudio's exacting specs or, in the case of COTS (Commercial Off-The-Shelf ) parts, top-quality, these are rigorously screened, and hand-matched to ensure consistency from side to side and from amp to amp. The 880M's slew rate is given as 70V/µsec, and even at 800W of output, Simaudio claims total harmonic distortion (THD) of less than 0.04%. John Atkinson's measurements will tell the tale, but these are impressive claims for a megawatt amp with no global negative feedback.

Even more impressive was how effortlessly the 880Ms delivered this performance—after long listening sessions at higher-than-normal levels, they were barely warm to the touch. According to Simaudio, the 880M run in class-A up to 10W, and thereafter in class-AB to its rated output. Simaudio believes that this approach provides the optimal mix of all-out performance and efficiency, and ensures long, trouble-free life by maintaining each amp's components in a cool, thermally stable environment and running them at only a tiny fraction of their rated capacity.

The 880M is physically impressive as well. Although substantial, it's not all that big—but it's Solid with a capital S. Its appearance mirrors those of other Moon Evolution components, with a richly finished case of black-anodized aluminum, and a heavy front panel comprising elegantly curved extrusions of brushed aluminum flanking a black or silver center section. Like the other Moon Evolutions, the 880M is made stable and mechanically grounded by the chassis itself and its precisely positioned, conical feet of hardened steel. Thankfully, small, indented steel pucks are also provided; slip these under the cones to prevent them from impaling your floor or equipment stand.

Comparisons from the Present
The Moon Evolution 880M is impressive in terms of technology, specs, design, and workmanship, but the true test of any component is how well it performs when the stylus hits the groove.

After a suitable amount of break-in, during which the amps remained powered up per Simaudio's instructions, I sat down to get a handle on what the 880Ms were and weren't doing in my system. I cued up Georg Solti and Chicago Symphony and Chorus's first recording, from 1972, of Beethoven's Symphony 9 (LP, London CSP-8), one of my "Records To Die For" for this year, which had been spending a lot of time on my turntable.

The first thing that got my attention was how different the 880Ms sounded from the VTL Ichibans and Mark Levinson No.20.6s, both of which I've been using for many years. I know those amps' limitations very well, and am willing to accept them because both are true to the music. Although dramatically different in format and technology, the VTLs and Levinsons—as well as most other top-shelf amps I've heard—provide a similar perspective on a performance.

It surprised me that the 880M's perspective was so different. Having just begun my listening, I wasn't yet prepared to say that it was better or worse, just . . . different. The first thing I noticed was that choristers in the final movement, instruments lower in the mix, the second and third chairs—all the lesser elements of the music—were much more apparent and contributed more to the performance, through the Simaudio. Conversely, first chairs, soloists, and strong melody lines were less prominent. If it hadn't been the same LP of the same recording, I might have suspected that I was listening to two different mixes of the same performance/recording. Whenever I switched from the 880Ms back to the VTLs or Levinsons, it sounded as if spot mikes had been added. The perspective still sounded natural, but different. Those second- and third-chair players, presented so clearly through the 880Ms, commanded much less of my attention.

My first impression was that the 880Ms' soundstage was foreshortened, its leading edge farther back than the other amps', and the rear of its stage more forward. The Levinsons produced a soundstage that was more recessed overall, but seemed deeper. The VTLs created a stage that projected farther forward than did the 880Ms, and had a beguiling way of floating those soloists and lead parts on a cushion of air at the front of the stage. The more I listened, however, the more I was struck by the consistency and stability of the 880Ms' soundstage. The VTLs' open, airy, forward projection and the Levinsons' depth began to seem slightly inconsistent, varying with the musical content and flow. Compared to the 880Ms' unwavering stability, the images projected at the front of the VTLs' stage, or the information at the very back of the Levinsons' stage, seemed to float at times, as if it were only tenuously connected to the rest of the soundstage. Plus, the rear corners of their stages would contract inward at times, matching the 880Ms' performance only at climaxes, when the sheer power of the music would push the rear corners outward; and during the softest passages, when the low-level reflections that defined the side and rear walls of the recording venue would be apparent. There was none of this variability with the 880Ms—the stage was always the same wide, deep, solid, coherent portrayal of the original recording space.

Individual instruments and voices within the 880Ms' soundstage had realistic, tangible body. Midway through Act 2 of Alain Lombard and the Paris Opéra Comique's recording of Delibes's Lakmé (LP, Seraphim SIC-6082), shortly after the beginning of side 4, Gerald (Charles Burles) enters and begins a duet with Lakmé (Mady Mesplé). It's one of my favorite scenes in the opera, and one I often use to evaluate how well a component reproduces the details and subtleties that give an image its realistic feel. When a component gets it right, Burles's presence is startling—it feels as if he's in the room with me. The 880Ms passed this test with flying colors, giving Burles a holographic three-dimensionality. Here, too, the 880Ms' sound was more consistent than the other amps', drawing my attention away from Burles to the other, less front-and-center characters, and to details of the recording space.