Sidebar 3: Measurements Despite its high efficiency, the chassis of the Bel Canto eVo 200.2 was warm after the one-hour preconditioning period at one-third power, though not nearly so warm as would be the chassis of a traditional amplifier with a class-AB output stage. The voltage sensitivity into 8 ohms was low at 24.2dB with both balanced and unbalanced inputs. The single-ended input impedance was a high 109k ohms, this approximately doubling for the balanced input. The amplifier was polarity-correct via both inputs (the XLRs are wired with pin 2 "hot").
The source impedance…
The active low-pass filter did come in useful for examining the Bel Canto's channel-separation and THD performance, however. Fig.5 shows the separation, adjusted for the filter's insertion loss. It is quite different in the two directions, the R-L trace showing the usual rise at high frequencies due to capacitive coupling, the L-R showing a pronounced minimum at 2.5kHz.
Fig.5 Bel Canto eVo 200.2, channel separation (10dB/vertical div., R-L dashed).
With the output-stage switching noise eliminated by the filter, the true level of measured distortion (fig.6) was low,…
Manufacturer's Comment Editor: Stereophile has again produced an accurate and informative review. We are proud of and excited by what eVo technology represents and brings to home audio. When we started our search for a solid-state technology that could capture much of the musical excitement inherent in a good single-ended triode amplifier, we did not know that it would be in the realm of the switching amplifier. Our first exposure to Tripath's new DSP switching amplifier technology demonstration board showed much promise, although it was seriously flawed for a high-end application. More…
Kalman Rubinson wrote a Followup in November 2001 (Vol.24 No.11): How do you know when your system is really loud? If you don't have a sound-level meter, you can wait for your neighbors to complain or for your ears to bleed. But long before that point, a system will begin to give telltale signs—like dynamic compression and increased distortion, which are often misinterpreted as meaning "loud" rather than "distorted."
Well, I don't generally get to that point with my regular equipment and musical preferences, and when I auditioned the $2395 Bel Canto eVo 200.2 power amplifier for…
Kal Rubinson wrote again about Bel Canto in December 2002 (Vol.25 No.12): I had reviewed the original Bel Canto eVo 200.2 quite favorably in the March 2001 Stereophile (Vol.24 No.3), but was somewhat surprised by John Atkinson's decision to put it in Class A of "Recommended Components." It was a breakthrough for high-end amps in terms of technology and efficiency, but it was less than the state of the art in transparency and lack of grain. Moreover, JA and I had problems getting it to put out full rated output because of its built-in protective current limiters. Snipping out the limiting…
Audio Artistry's Beethoven is the banner model of the company's Composer series (footnote 1), which includes the entry-level Vivaldi as well as the Dvorak I reviewed in the April 1996 Stereophile (Vol.19 No.4, p.204). Like the Dvorak, the Beethoven is a four-piece, bi-amplified, dynamic dipole design; unlike the Dvorak, the Beethoven has been taken to the nth degree of refinement. Since many of the major design features common to both speakers were described in depth in the Dvorak review, only the most salient characteristics shared by the Beethoven are revisited here. Those interested…
On the faceplate you'll find a blue operating LED and a button labeled "Video." Pressing this button minimizes subwoofer excursion when playing back very loud explosions on some laserdisc and DVD soundtracks, or the intense subsonic rumble occasionally heard on LPs. This is accomplished through a gentle 6dB/octave rolloff from 40Hz on down. On the rear of this chassis are a DIN connector for attaching the external power supply, and switches to turn each subwoofer on or off. Separate woofer-level knobs are also provided for up to 12dB of adjustment in order to match the system to…
This perennial problem is a little like peeling an artichoke. As you strip away successive layers of coloration and distortion, the taste becomes increasingly subtle and succulent, yet there always seems to be another layer to remove. I've no doubt that the same analogy will apply to future refinements in the art of speaker design, yet the amalgam of attributes resulting from the many choices embodied in the Beethoven constitute much more than an incremental step forward. Indeed, the overall results are so compelling that one can be forgiven for mistaking a wonderful late-night symphony…
Another benefit of the Beethoven's resolving power was that I could hear the tangible nature of good music whether I turned the volume up or down. When gradually turning the volume up with my remote-controlled Rowland Coherence preamp, I had the distinct sensation of my chair being pulled closer to the stage. Turning the level down, the perception was reversed: I felt slowly drawn back up the aisle, all the while still experiencing the spooky sensation of breathing the same air space as the performers! Also, without the averaging impact from room-masking, I discovered that favorite…
More important, though, is the aural break-in often required by the listener with this class of speaker. Without the room masking and excess bass many audiophiles have become conditioned to, you'll hear both a lot more and a lot less than you're accustomed to hearing from favorite recordings: less coloration and more musical detail, particularly in the lower midrange and bass. My experience was that, as I listened to an ever-greater variety of music running the gamut of recording quality from poor to awesome, the deeper my appreciation grew for the "rightness" of the Beethoven's performance…
