Power Amplifier Reviews

My own live concert recordings of the Boulder Philharmonic, recorded with a single phase-coherent pair of Schoeps microphones, provide an excellent window of proper depth and imaging. When the eVo2 amplifiers were tethered to a top-flight preamp-processor, such as the Meridian 800 or Lexicon MC-12, they did a superb job of preserving the separate rows of instruments in their places on the concert stage. The brass came from behind the woodwinds, while the second violins and violas were in front of the woodwinds, just as they should be.

Compared to such an exacting source, pop recordings and movie soundtracks were relatively simple to re-create accurately. On the Smith Music Group's excellent live concert DVD of Asleep at the Wheel Live at Billy Bob's Texas, every instrument was locked in to just the right location, and the crowd noise was layered to the very back of the mix.

The eVo2s' lateral image specificity ranked right up there with the best solid-state amplifiers I've heard. The Pearl Harbor DVD provides an excellent test for lateral tracking of a surround-sound system. Close your eyes during the combat sequences and see if you can pinpoint where a plane should be by the sound of its engines, then open your eyes to find out where it is onscreen. If the surround system is doing its job, the plane should be where you expect it to be. With the eVo2 amplifiers installed, my system passed the Pearl Harbor test with (ahem) flying colors.

Audiophiles often talk about micro- and macrodynamics. Macrodynamics refers to a system's total dynamic range from loud to soft, while microdynamics concerns the subtle differences between small changes in volume. Most decent amplifiers can get the macrodynamics right, but mastering microdynamics separates the merely good amplifiers from the truly great.

Given its power capabilities, the eVo2 will play effortlessly at high SPLs with any THX-certified speaker, or even non-THX speakers with 90dB/2.83V/m sensitivity. My Genesis speakers are rated slightly less than 90dB/2.83V/m and present a very difficult load. But the Bel Cantos had no problem driving them well past the human pain threshold. I would expect no less at this price point.

Measured by the more demanding yardstick of microdynamics, the eVo2 did an even more exceptional job, showing what can be accomplished with a simple circuit. During the opening credits of Hedwig and the Angry Inch, subtle variations in volume prevent the music from being just a solid wall of sound. The eVo2 let the music's pulse, or pace, come through clearly.

Back in audio's bad old days, you could easily tell the difference between tube and solid-state amplifiers by concentrating on their degree of electronic "grain." This grain is the texture behind the sound, similar to the texture in an analog photograph. Film with greater sensitivity has more grain. You can see the same thing even in digital photos, where high sensitivity settings invariably have more digital noise. Tube amplifiers homogenize or smooth the grain so that it isn't readily apparent. Mediocre solid-state amps can make grain seem like an annoying, unmusical buzz behind the sound. The Bel Canto eVo2, while not completely free of the phenomenon, had an exceedingly fine grain that was on a par with the best solid-state amplifiers I've heard.

For reproduced music to sound alive, an amplifier must be able to pass the signal without slowing its transients, and this ability to properly portray transient speed requires circuits that don't compromise phase coherence. The eVo2 definitely qualified as "speedy." Its simple circuits and clever DSP allowed the signal to emerge with much the same phase relationships as it had when it entered the amplifier. (This was especially evident to me on my own live recordings.) Even on dense, difficult-to-reproduce material full of complex musical signals, the eVo2 didn't smear the transient information. During the live concert segments of the Standing in the Shadows of Motown DVD, the eVo2 handled the transients accurately; the liveliness of the performances remained intact.

You might think that home-theater power amplifiers don't need to do low bass because, in most cases, bass frequencies in the satellite speakers are rolled off to a powered subwoofer. But SACD and DVD-Audio often exhibit the full frequency range in all channels. In both of my systems I set the bass rolloff at 40Hz, even with films, but when playing SACDs, I send the speakers a full-range signal. Many audiophiles prefer a similar arrangement; for them, a fine high-end amp must be able to plumb those bass depths.

In all cases, the eVo2 didn't shut up—it put up. The multiple double-bass lines on the first cut of Super Bass 2 (Telarc SACD-63483) make an amplifier work hard, but the eVo2 delivered all these instruments' low-frequency nuances with no sign of stress. I was especially impressed by the eVo2's ability to supply low-bass weight while retaining the bass's upper frequencies. The double basses' notes sounded complete, the proper low-frequency attack combined with the right amount of decay.

Most advocates of tube amplifiers point to the midrange as the one area where solid-state amps can't match tubes' preeminence. Although the eVo2 did handle the middle frequencies very well, it sounded far more like a good solid-state amplifier than a tube amp in this range. The eVo2's midrange had a matter-of-fact quality similar to that of the EAD PowerMaster 8000, but without the 8000's extra bit of warmth in the lower midrange. When the source had extra midrange bloom, the eVo2 let it come through, but without adding any extra romance.

Class-D digital amplifiers are often used in powered subwoofers, but they're rarely used for full-frequency power duties because they don't reproduce high frequencies accurately. Because of digital amplifiers' reputation for poor treble performance, I spent much of my time with the Bel Canto eVo2 listening for high-frequency anomalies. Instead of a harsh or ragged high end, I found the eVo2's high frequencies to be sweet yet open. The eVo2 did an exemplary job of properly rendering violins and piccolos on classical recordings. Even on difficult-to-handle recordings such as the SACD of Cyndi Lauper's She's So Unusual (Epic ES 38930), where the cymbals sound more like frying eggs than musical instruments, the eVo2 produced a truthful, if painful, picture of the cymbals'sound.

The Fat Lady Sings
Usually, when a company rolls out a radical new design, the actual product doesn't come up to the promise of the new technology. Bel Canto's eVo2 power amplifier is an exception. It not only delivers the ergonomic advantages of compact size, light weight, low heat, and efficient energy usage, it also sounds spectacularly good.

Anyone who plans to assemble a top-flight, no-holds-barred home theater simply must audition the Bel Canto eVo2. It will produce more than enough clean, effortless power to drive even difficult speakers with finesse and aplomb. Need a superb amplifier for your new space-age system? Welcome to the 21st century of digital amplification—the age of the eVo2.