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Bel Canto REF500M Monoblock Power Amp
by Ernie Fisher

If you believe that high-end audio is always expensive, you are right — most of the time. There are, however, some, or few exceptions. These monoblocks cannot be considered outright bargains, but when one considers the price/performance ratio, one of the few exceptions is this pair of amplifiers from Bel Canto Audio. The price may point toward shortcuts taken to reduce costs, but that simply isn’t so. The company and its designers have a sound background in engineering and they have gone to great lengths to create electronic components employing the most recent and innovative advances in switching technology. While this is important, Bel Canto haven’t forgotten about the music their designs must recreate; after all, loosely translated, their name translates into Beautiful Song from the Italian language. As we shall see when you read the following, there is evidence that the components under review are capable of reproducing just that. Bel Canto has been in business for over 11 years and is headed by John Stronczer. Their earlier components included some vacuum tube designs, but the amp under review is a noteworthy example of the relatively new development of Class-D, or more precisely, a switching amplifier design. This technology has evolved tremendously, and whereas it was mostly used to power subwoofers, quite a few serious manufacturers felt that it has certain advantages over Class-A and AB topologies. Class-D guarantees high power efficiency without energy losses encountered by standard designs. It is known that the (theoretical) efficiency of Class-D designs is 100%, though over 90% is more realistic in audio applications. When compared to the efficiency of Class-B designs, which ranges around 50%, a switching amp uses little operating power while it provides oodles of output power.

Most power amplifiers are large, cumbersome components with which to impress the impressionable. The REF500Ms, on the other hand, actually enhance a listening room’s appearance because they are small, almost cute, and both units can easily be accommodated on a shelf that usually holds only one power amp. This may not be important to a hard-core audiophile, but it would likely be important to those who favor an uncomplicated system setup that also looks neat and uncluttered. The faceplate sports one indicator light mounted in the centre on a black background surrounded by part of the chassis. The chassis is made of aluminum, which wraps around the component resulting in an elegant, modern design that will complement almost any décor.

The Sound
For the auditions, I had my own Ethera Vitae, the Reev Design Aatma, Gershman Acoustic and Audio Physic speakers on hand. The Allnic L-300 (tube) preamplifier, XLO and Argentum speaker cables and interconnects and a CD playback system with word clock, DAC and transport made up the balance of the system.

After I had “cooked” the amplifiers for a couple of weeks, I began my sit-down listening to some of my most demanding recordings, beginning with JVC’s Beethoven’s 5th with Fritz Reiner conducting the Chicago Symphony. This masterpiece of orchestral work has, in addition to 55 instruments, the dynamic range of a bomb blast as well as the most delicate whisper of strings and is quite difficult to reproduce. In particular, the third movement demands quick transition from pianissimo to fortissimo passages and I have found that many amplifiers can’t handle this appropriately. However, the 500Ms dealt with this astoundingly well, with exceptional force and vigor at the forte and fortissimo passages and admirable finesse at barely audible pianissimo segments. Cellos and basses were clearly audible at stage right, and there was no unfinished business at the low frequency scale — lower than 160 Hz. That is bass energy done right, and confirmed with later listening tests of Bach’s Toccata in D Minor — a Dorian recording of the great organ of St Eustache. These amps will reach as low and with absolute resolution as the loudspeakers are able to reproduce, without a doubt some of the best bass I have ever heard. While I expected this, based on the design and previous auditions of the Bel Canto integrated amp, the S300I, I was quite surprised at the monoblocks’ handling of the other important frequencies — the midrange and highs. Frequencies from 160Hz to about 1300Hz (midrange) had liveliness — joie de vivre and spirit — that conveyed the essence of human voice, the timbre of instruments and the harmonic makeup of the music. It was not the best I have heard — that is with very expensive amps — but it was without edginess and/or harmonic shortfalls. My surprise continued when I analyzed the amplifiers’ performance in the very top frequency regions (from 5000Hz to about 10kHz) where instruments, such as horns, violins perform and where loads of harmonics live. With the less expensive Argentum cable, this part was smooth, perhaps a bit too smooth to call it precise, and also a little on the dull/dry/boring side. However, when I changed to the XLO cables, the sound became lively, involving and refined. At one time, I would have said that the amps reproduce inner detail properly, but after having re-evaluated the terminology I (and many others) have used for many years, I would say that the Bel Canto amp “does” detail sensibly composed, not highlighting it, but presenting it with realism, well balanced with all other musical information. This is, in fact, authenticity rather than “enhanced reality” which caters more to personal whim and/or the listeners’ partiality. Most of my listening tests include material with various brands pianos and I pay attention to the pianos’ sonic makeup. The pianos I am familiar with are grands from Steinway, Boesendorfer, Yamaha and Baldwin — and when I hear them reproduced well, my music-lover soul delights and my reviewer brain nods with approval. Well, I nodded a lot, sometimes surprised, sometimes in admiration of the Class D technology, which, in my opinion, has come a long way in this design. All aforementioned loudspeakers used for this evaluation worked well with the amplifiers, thus indicating that the amps boast admirable sonic neutrality, which likely marries well with all sorts of speaker designs. As my main interest is not the technology used here, I am obliged to point at the way technology benefits the music lover, listener — and this is where the Bel Canto does the job very well indeed.

Synopsis & Commentary
In the business of electronics, sonic differences abound and I believe that the job and obligation of a reviewer is to make these differences known to the readers. It isn’t enough to describe sound as hard, soft, mellow, strident, glaring, smooth, masked, irritable, appealing, lush, bright, dark etc., etc . . . What is important to know is how things sound, that is the amplifiers (in this instant) — and how it makes things/music sound. Well, these monoblocks sound not only good, they also provide a fine listening experience when one considers musical elements such as detail, dynamics, sound staging and harmonics. I suggest the use of a good preamplifier and source component as well as premium interconnects and speaker cables so as to make the most of the Ref 500M’s capabilities. With a good system combination, these amplifiers provide more musical entertainment than much higher priced components I have heard. The price is right, the performance is excellent and the entertainment value is off the chart. Great job Bel Canto.

REF500M Mono Amplifier Bel Canto
$4,000.00/pair (CDN)
Size: 8.5 x 3.5 x 12[inches], 216 x 88 x 305[mm] (WxHxD)
Weight: 15 lbs, 7 Kg


Bel Canto calls its design High Dynamic Range Audio Amplification, which provides
“an unprecedented level of sonic accuracy and power” to the loudspeakers.
The REF500M delivers 121dB dynamic range and 250 watts into 8 ohms, doubling to 500 watts into 4 ohms. The combination of fully regulated switch-mode power supplies and analog control circuitry results in tremendously wide dynamic range. Switching amplification technology has many advantages including low noise, low heat and low power consumption. Additionally, it is said that the design is the most direct way to convert electrical power into an audible signal — music.

The Ref 500M power input stage boasts high speed, low noise rectifiers and large storage and filter capacitors that increase energy storage while lowering noise and reducing sensitivity to power line fluctuations. The input stage employs the most advanced components including: Caddock resistors, Solid Electrolytic ultra-low ESR decoupling capacitors and low noise regulated power supplies. The switching output stage eliminates thermal distortion mechanisms caused by changes in operating temperature. Green, low-heat, ultra-efficient heavily regulated switch-mode power supplies and switching output stage enables an eco-friendly compact design with a heavy gauge, all-steel chassis that prevents micro-phonic noise from corrupting the audio signal.

Now to the impressive specifications:
Maximum Power Output: 500W 4 ohms, 250W 8 ohms;

Power Output 1% THD: 450W 4 ohms, 225W 8 ohms;

Minimum Load: 3 ohms; Peak Output Current: 35 amperes;

Frequency Response: +/-3 dB 1.5Hz-70KHz, all loads;

THD+N: 0.003% 1W, 1KHz, 4 ohms; IMD (CCIF): 0.0003%, 1W, 14:15KHz, 4 ohms;

Output noise: 35uVRMS A-weighted 10Hz-20KHz; Voltage gain: 27dB (single ended or balanced input);

Damping factor: >1000;

Output Impedance at 100Hz: <8 milliohms; Dynamic Range: 121dB; Input Voltage for Max Output: 2Vrms;

Input connections: Single-ended RCA or balanced XLR;

RCA input impedance: 100Kohms; Balanced input impedance: 200Kohms;

Output connections: 1-set WBT Nextgen 5-way binding posts; Power On usage: 10W;

Power Off usage: 0.0W
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