Solid State Power Amp Reviews

While I found it mostly smooth sailing, at one point the Ethernet connection between the ASC1 and the JRiver player on my computer broke, making inaccessible hundreds of great files I'd wanted to play from an external drive—all I got was sound from the computer speakers. Nothing I could think of doing solved the problem. I ended up shutting down and restarting the ASC1, but only after half an hour of hair-pulling frustration.

Computer audio is still in a messy state of glitches, unreliability, and nonstandardization. It's something everyone involved in it faces, and everyone wishing to jump in will have to face. But that was the only glitch.

Sound
My experiences with class-D amplification have been mostly disappointing. If you read Kal Rubinson's review and my review of the Anthem Statement M1 monoblock ($6998/pair), both published in 2012, you'll find remarkably similar descriptions of its sound. Later that year, when I reviewed the Mark Levinson No.53 class-D monoblock ($50,000/pair), I said: "As seems to be the case with switching amps, no matter how carefully designed, the higher in frequency the music goes, the more problems there are."

I spent a great deal of time with the Black, listening to digital and analog sourced recordings, including many of the same ones I'd listened to through the No.53s. This made a few things obvious. First, this system is the best-sounding implementation of class-D technology I've heard, especially with digital sources. After every digital listening session, I concluded, "If you're going to go digital, this is the way to go"—by which I meant: Keep the signal in the digital domain until just before it's sent to the speakers.

Through the Black and the first of its three filters, high-resolution files and CDs produced the full measure of dynamic authority always promised by digital but seldom delivered. The Black's re-creation from digital sources of three-dimensional imaging and soundstaging was the most intense and compelling I've heard, with well-carved images presented against "black" backdrops.

From the Meridian Digital Media System I played CD-resolution files of Bob Dylan's Time Out of Mind (Columbia CK 68556) and Highway 61 Revisited (Columbia CK 9189), which usually sound flat and drab. They were still drab, but the amps and DAC (which can't be separated) suppressed the expected harshness, grain, and general unpleasantness, leaving a refreshing clarity of instrumental line. The strummed guitar and piano in Highway 61 Revisited, which usually sound like indistinguishable mush compared to the LP, were reasonably well separated. I could actually hear the skin on the tambourine in the right channel. Vocal sibilants didn't overwhelm, as they usually do when I listen to a digital version of this album, and Dylan's voice had a presence that was pleasingly compact, three-dimensional, and well-focused.

The Meridian offered surprises wherever I went: the CD-sourced Saturday Night Live: The Musical Performances, Volume 1 (CD, DreamWorks), for instance, which had always sounded mediocre to me, now drew me in: from first (Paul Simon singing "Diamonds on the Soles of Her Shoes") to last (Randy Newman singing "I Love L.A.)," I listened straight through to all 15 tracks. Why? For one thing, as you'd expect from a class-D amp, the bottom end was fully expressed and robust, which provided a taut rhythmic ride. But beyond that, there was imaging and staging, and though the picture was generally dark, there was a welcome lack of grain, glaze, and glare.

Like the Mark Levinson No.53's bottom end, the Bel Canto Black's was fast, well controlled, and fully extended. I called this "depth-charge bass" in my review of the No.53, though I thought it could have used some more weight, and definitely more body. The Black's bass weight and body were ideal. When I switched to "I Want to Be Your Man," from the Rolling Stones' Singles Collection: The London Years (3 CDs, ABKCO 1218-2) I found the articulation and texture of Bill Wyman's bass to be better than I'd ever heard it. I liked how kick drums sounded through these amps—the bottom octaves weren't overdamped, and drumskin textures didn't disappear into dryness.

While in 2012 I'd said, "If you like your midband rich, you won't get it from the No.53," in 2015 I did get a rich midband from the Bel Canto Black. And while I'd lauded the No.53 for its "overall transient precision, superb if not unprecedented speed and clarity, resolution of inner detail, and black backgrounds," I also complained about "a dose of listening fatigue partly caused by high-frequency hardness, and partly by the overall dryness, which also produced well-rendered outlines but little in the way of nuanced textures: all outer shell, very little creamy center." Not so here. The Black's midrange was reasonably rich, and there was no high-frequency hardness.

But I'll stick with "the higher in frequency the music goes, the more problems there are." Bel Canto apparently solves such problems withholding the upper octaves—or at least, that's how it sounded. No doubt the measured response will be flat.

Air and space were in short supply, as was generous or even perceptible instrumental decay—things that are also in short supply on "Red Book" CDs, so I hardly missed them. But the Black's suppression of all the upper-frequency hash and digititis of CDs, combined with well-finessed transients that were neither too hard and etched nor too soft and mushy, an attractive midrange, and a full-bodied bottom end, made it no wonder that I found CDs so engaging.

Were I a "Red Book" guy, I'd consider chucking whatever I had and buying a Black—and that would be true even were I a classical-only "Red Book" guy. I played straight through a disc of Antál Dorati leading the London Symphony in music by Schoenberg, Webern, and Berg (CD, Mercury Living Presence 432006). Everything I can't stand about CD sound had gone missing; what was left was well rendered, dynamically, texturally, and, most important, harmonically—though with reduced air and less-than-generous upper-octave extension. I'll take that, every time, over sizzle and tizz—of which there were none.

I did experiment with the Black's minimum-phase apodizing filters—Filter 1 (flat to 20kHz), Filter 2 (–3dB at 20kHz), and Filter 3 (–9dB at 20kHz)—and even turned off the filtering altogether (Standard Linear Phase). For CD playback, I preferred Filter 1. I'm not suggesting that these days I can hear anything above 20kHz or even close to it, as I once could (I used to be able to hear the 15.734kHz tone from an NTSC TV's flyback transformer), but with no filter, the top end had a slight added crispiness that produced nothing useful.

High-resolution files
Not surprisingly, really well-produced hi-rez files, whether sourced from a digital or an analog master, delivered more graceful transient attacks, greater spatial contexts, and generally fewer cardboard-cutout pictures.

I have some legally obtained 24-bit/192kHz master files from Blue Note Records, and played half a dozen of them while evaluating the Bel Canto Black. Cassandra Wilson's essential album New Moon Daughter at 24/192 was a real treat, particularly its robust, well-textured bottom end. Still, I found the guitars somewhat lacking the sparkle and air I'm used to hearing; decays were usually fast fades to black, and Wilson's voice was somewhat closed in, hanging starkly in space unsupported by air. I'm used to more generous sustain, and more air around instruments and voices. Reverb tails were shortened. Still, the "black" backgrounds and authoritarian bass control were more than ample compensation. It's all about being drawn into the music—if the CD-resolution file managed to do that, you can be sure the hi-rez ones did too.

These minor acts of omission or commission aside, the Black's sonic picture was velvety-rich, three-dimensional, and free of grain, glare, hardness, and—especially—the haze that had so bothered me in the sounds of the other class-D amps I've reviewed.

Digitizing vinyl?
Playing vinyl, using the ASC1's analog input, was interesting. Shadows in the Night, Bob Dylan's tribute to Frank Sinatra, was recorded at 24/192 but never mastered (CD, Columbia 57962). Instead, the reference CD that engineer Al Schmitt produced for Dylan to listen to in his car ended up being the "as-is" master, and the vinyl was cut from it. I knew that when I wrote my review of the album for AnalogPlanet, but at the time, I'd promised my sources not to reveal it. Yet the vinyl sounded far more three-dimensional, harmonically and texturally more convincing, so that's what I wrote. In comparison, the CD sounded drab and flat.

Now, playing the LP mastered from a CD-resolution source but digitized by the Black at 24/192 and comparing it to the CD was doubly interesting. Though far better than I remember it sounding through my reference system, the CD was still spatially flat and harmonically drab compared to the digitized LP—for example, the horns in "The Night We Called It a Day" and, especially, Dylan's voice throughout. On the CD, both sound harmonically monotonous, texturally flat, and pressed up against the speakers. The "24/192 vinyl" for the most part preserved the space, the pedal steel's natural ebb and flow, and especially the textures of the trumpet and Dylan's pleasantly weathered voice. If these are "additive distortions," I don't care.

I played dozens of LPs with the Black and also 24/96 rips from vinyl that I've played many times, here and elsewhere. I concluded that, for better or worse, the Bel Canto Black system's sonic signature, more than the digitization, was what dominated the sound, though there's still something "different" about digitized analog, just as there's something "different" about class-D amplification. To paraphrase what Supreme Court Justice Potter Stewart famously said about obscenity: I can't tell you what it is, but I know it when I hear it. Here, though, compared to my other experiences of class-D, I very much enjoyed listening.

Conclusions
Black by Bel Canto Design is a breakthrough product and, because of its sound quality , the most intriguing one I've reviewed—and by now, that's a lot of products. Its operating flexibility, system integration, and ease of use alone make it a must-experience product for audio enthusiasts looking for a unique, 21st-century listening adventure.

If you're a digital-only audiophile, particularly a 16-bit/44.1kHz "Red Book" one, you might find the Black's the most compelling digital sound yet. I did, and I don't like CDs at all. Yet I found some respite with the Black, and not because it obscured the problems many of us have with CDs—in fact, the opposite.

The Black's reproduction of hi-rez files produced the expected sonic benefits. Live digitized vinyl playback sounded more similar to than different from hi-rez digital files, but through the Black, all of these formats sounded very different from how they sounded through my reference non–class-D system: CDs for the better, the others less so. Class-D amplification sounds fundamentally different. In the case of the Bel Canto Black, it can be credibly argued that it can sound better.

If you're a committed analog listener, you're probably going to want to listen to vinyl in the analog domain. (But if you have an opportunity to hear an LP through this system, do it.) Otherwise, here, finally, is a class-D product that, though sounding definitely different from the older technologies, makes a strong case for equality. That's saying a lot.