Bel Canto Design e.One REF500 Mono
by Bob Wood
||"The REF500s were
of a rare variety that displayed dynamic prowess, perhaps due to their lower overall
gain." "This lower-than-usual level resulted in plenty of "there" there,
without thinness. Voices seemed especially lifelike, and I noted more chest than throat. Even
at low volume, there was plenty of resolving power." "I also heard the effects of a
low noise floor, which were noted as a more resolving, involving, and detailed sound. In other
words, even at low levels, I could hear low-level detail."
balanced] Bel Canto REF500...represents a new generation of the company's e.One switching
amplifiers -- the second iteration, containing the third version of B&Os ICEpower
module." The input stage is "tweaked with Caddock resistors, low-ESR decoupling
capacitors and low-noise regulated power supplies. The target benefits are reduced sensitivity
to power-line effects, lower noise, better power delivery, and increased dynamic
capability." "The REF500s are rated at 500 watts into 4 ohms and 250 watts into 8
||"Under the caveat
"your mileage may vary," your choice of cables with the REF500s will help you fall
in love or drive you to divorce. The best advice I can offer is to experiment."
"There are no air vents, and they are not needed. At my listening levels, the amps
reached only a warm level."
||"They are a step
forward in the march of class-D amplification into the world of organic high-end audio."
Class-D amps suffer from a couple of widely held
misconceptions: "D" stands for "digital" (not true) and brings with it
nasty artifacts (not always true) versus the smoother sound of conventional
"analog" amplifiers. In reality, class-D amps, also called switching amplifiers,
switch their output devices on or off at very high speed. This allows for great
efficiency, as more than 90% of the input current is converted to output power. Plus,
class-D amplifiers can be bantam weight and tiny when compared to the much heavier
traditional amplifiers. Because class-D amps dont generate much heat, heat sinks
arent necessary. To some, light weight equates to fewer parts, less circuitry and
The Bel Canto REF500 ($4990 USD per pair)
represents a new generation of the company's e.One switching amplifiers -- the second
iteration, containing the third version of B&Os ICEpower module touted to
increase clarity and improve high-frequency extension while lowering high-frequency
distortion. The ICEpower module contains its own switching power supply, which can accept
either an AC or DC input. Bel Canto cascades its own proprietary 300-volt DC power supply
ahead of the ICEpower module. This, Bel Canto feels, cuts noise and, with more energy
storage built in, gives more weight or "gravitas" to the sound. Together, these
are said to effect a cleaner, quieter sound.
Then theres the input circuit. It is
tweaked with Caddock resistors, low-ESR decoupling capacitors and low-noise regulated
power supplies. The target benefits are reduced sensitivity to power-line effects, lower
noise, better power delivery, and increased dynamic capability. So the REF500 isnt
simply an off-the-shelf module inside a fancy box. Bel Canto has gone to great lengths to
find ways to improve what comes stock from B&O. The final design is auditioned
in-house on electrostat, ribbon, and dynamic speakers.
The REF500s are rated at 500 watts into 4 ohms
and 250 watts into 8 ohms. If you want more power, the REF1000s double this output. The
damping factor for the REF500 is greater than 1000. Dynamic range is specified at 121dB.
Frequency response is given as +/-0.5dB 20Hz-20kHz. Each amp weighs 15 pounds and measures
8 1/2"W x 3 1/2"H x 12"D.
The industrial design is first-rate. The
minimalist front plate, a dark panel with a blue power LED, is framed by a surround of
substantial silver edging sporting an engraved Bel Canto logo. On the rear youll
find switchable balanced XLR and single-ended RCA inputs (the REF500's circuit is fully
balanced), five-way WBT speaker binding posts, a power switch, and an IEC power-cord
receptacle. There are no air vents, and they are not needed. At my listening levels, the
amps reached only a warm level.
System and setup
My gear includes a VSE-modified Sony SCD-1
CD/SACD player, a Great Northern Sound-modified Audio Research LS5 Mk III preamp, and
Wilson Audio WATT/Puppy 7 speakers. All interconnects are balanced Audience Au24. Speaker
cables are also Audience AU24. Power arrives from a dedicated 100-amp breaker box, with
each dedicated outlet filtered by Audience a1Rp conditioners. The CD/SACD player and
preamp rest on Aurios footers and a Salamander rack that is inset into the wall and backs
into a closet. Power cords are Electraglide Reference Fatboys. I recently replaced NuForce
9 SE V2 monblocks with a single Classé Audio Delta CA-2200 stereo amp. The room was
designed by Rives Audio.
While Bel Canto has made some effort to reduce
the effect of interactions with wires, known to be a class-D issue, when I swapped out my
Electraglide power cords for what I believe are an old pair of Bybee PCs I had cryo'd, I
did hear a difference, as I would ascribe much more etch to the Bybee cords. This was most
noticeable on poorly recorded or hammered-with-processing CDs. Under the caveat "your
mileage may vary," your choice of cables with the REF500s will help you fall in love
or drive you to divorce. The best advice I can offer is to experiment.
Regarding burn-in, I listened to the REF500s
right out of the box to simulate an impatient new owner, then again at 50 hours, and
finally did the bulk of my listening after 300 hours. No question, the impatient buyer
will be disappointed. The sound is congested and muffled, and the soundstage is
constricted. At 50 hours, the improvement was obvious. The presentation opened up,
displaying more more air and ease. At 300 hours, I settled in for extended listening and
heard what I describe below.
The Bel Canto REF500 is the seventh class-D amp
Ive heard in my system. Each sounded different from the others. There was something
missing, hyped or transformed in the lower mids to upper bass that flavored many of the
class-D efforts Ive heard. Also, some designs came down on the analytical side of
the spectrum, noted in the high frequencies with greater edginess, while others were more
organic. All seemed to feature great bass.
The REF500s were of a rare variety that displayed
dynamic prowess, perhaps due to their lower overall gain. This resulted in a playback
level that had me leaving my chair to turn the music up and engendered listening
satisfaction. I listened through CDs completely, enjoying it all. I don't mean to imply
that there was something added at low volumes or subtracted at high ones; such was not the
case. With the 19-track compilation CD Dont Mess With Texas (TMP Music
310304), which was recorded in many studios by many artists, the vocals were clear with no
hint of grain. The presentation wasnt euphonic, as the wide variety of performances,
studios, and mixes still showed distinct character. This lower-than-usual level resulted
in plenty of "there" there, without thinness. Voices seemed especially lifelike,
and I noted more chest than throat. Even at low volume, there was plenty of resolving
I then put on a CD that was highly touted once
upon a time: James Brown Live at the Apollo (MFSL UDCD583). I had only listened to
it briefly, disappointed, and filed away years ago. Now I understood why this
seminal performance was so well regarded. Its odd in a way: Brown is in one channel,
the Flames are in the other, and you almost wish for a flip switch so you can put him in
front of the band. The audience is heard in both channels. He could clearly hypnotize an
audience -- a master entertainer in an amazing performance. The air was clean, scrubbed by
the call and shrieking response between performer and audience, and all the while the band
pulsed in soulful power. Even the shrieks were clean, and there was no shatter to the high
I also heard the effects of a low noise floor,
which were noted as a more resolving, involving, and detailed sound. In other words, even
at low levels, I could hear low-level detail. I eventually cranked up the volume. I
probably know Steely Dans Gaucho SACD (Universal/MCA 7048) better than any
other disc in my collection. I never tire of it. My notes again indicate more chest than I
am used to on voices, even within the choruses, which were exceptionally well resolved, as
was the voice of lead singer Donald Fagen. I could hear the clarity of his voice on
"Chase the Dragon" and "My Rival." I wrote in my notes: "a
righteous mellowness serving the music appropriately -- the reeds, horns,
synthesizer." Translate that to mean there was plenty of swing. Think of organic
sound, just as in real life.
Through the REF500s, the drum-and-bass intro to
"Babylon Sisters" was sized just right. The extremely subtle, whispered
"Santa Ana winds" was right there, fully present. Choruses appeared deeper in
the soundfield, yet were clearer and better resolved than Ive heard. Crescendos were
free of any sonic pollution. And I found that this disc, which has always sounded rather
dry, to have some soft reverb overlaying the music. Again, thats resolving power.
Theres a nice mellow side to Steve Miller
on his Born 2B Blue CD (Capitol C2-48303). With the Bel Canto amps, little tastes
of ear candy (guitar licks, picks, finger snaps) popped out of the mix, hard left or
right, sometimes seemingly forward of the soundstage. On this disc, Miller's close-up,
layered, intimate vocals appeared and disappeared into thin air like slow-motion bubbles.
On "Filthy McNasty," Bobby Malachs saxophone was holographic. Billy
Petersons purring bass line was like a big cat. On the title track, Milt
Jacksons vibraphone was palpable. The significance of what I heard here is that the
position and depth of the little touches were easily distinguished -- not lost in the
louder music. With some amps, they are also too bright, in others dulled by the
surrounding louder material.
Playing the SACD from Jaco Pastorius's Big Band, Word
of Mouth Revisited (Heads Up HUSA 9078), I was impressed by the cut "Barbary
Coast." This is exciting and alive with dynamics. Definition -- from cymbal shimmer
to brass blat to bass runs -- and staging brought the band into the room. How could anyone
hear that and wonder about whether class D has arrived? This cut had the impact of a
Big Countrys eponymous debut CD (MCA MCAD
11446) always seemed to me to have just a touch of edge to the vocals. Through the
REF500s, though, what was once misheard as a trace of spit resolved itself into very
closely doubled vocals. The well-recorded guitars and harmonica imaged appropriately on
point. I believe I heard more detail to pick up the vocal trick, but not at all in any
James Taylors new Covers CD (Hear
Music HRM 30829-02) seems to have been recorded with great care. Taylor's voice is the
standout. It sounds real -- completely unprocessed. With the Bel Canto amps, the horn
section, the strings, and the backup singers were nicely present. Listen to the intimate
violin on "Wichita Lineman" and the gentle brushes on the drums in the
background. Or check out the dynamic drive to "Its Growing" or "Some
Days You Gotta Dance." The REF500s delivered this musical detail intact, including a
superb vocal presentation with plenty of body weight, not just nose and throat.
Consider a line between "analytical"
and "organic"; you can draw another line parallel to it stretching from
"thought" to "feeling." The REF500s live on the "organic,"
"feeling" side of this continuum. There was a sense of effortlessness -- no
strain or disproportion. Initially I thought the REF500s might be a little bass shy
compared to other class-D amps Ive auditioned, giving the lower mids more
prominence, but I came to feel this was more in comparison to what I was used to hearing,
rather than a true characteristic of the amps. Its in this frequency range that
Ive heard a darkness in certain other class-D amps. Ive also felt that some of
the others had hyped lower-bass prominence. Not so with the REF500s.
Since Id just sold my NuForce 9 SE V2s
($5000 per pair), I couldnt play them side by side to compare directly to the
REF500s. Still, the impressive NuForce amps seemed to go lower in the bass and were more
analytical in the highs. The REF500s countered by making music sound more natural and
real. The last amp I reviewed, the Classe CA-2100 ($4000), a conventional class-AB amp,
certainly had a different, brighter texture to the lower mids in direct comparison to the
NuForce amps, and a greater sense of rhythmic drive than the REF500s.
As for imaging, I heard more soundstage detail
than I am used to with the REF500s, but the soundstage itself didnt extend beyond
the usual in my room. The stage spread wasn't wider than my speakers, which, with some
material, can wrap around me 270 degrees.
Each of these amps has obvious strengths, but all
of them sound rather different. If you value the musical realism brought about by a more
relaxed presentation, the Bel Canto REF500s are the amps to audition -- and perhaps buy.
Efforts at Bel Canto to improve the
third-generation ICEpower module seem to have succeeded. The REF500 monoblocks delivered
on the promise of low noise, as evidenced by good detail retrieval and heft amidst notable
dynamic drive and power. They were subject to burn-in and cabling issues, as most amps
are. I enjoyed my time with them and suggest a personal audition -- just be sure they are
fully burned-in before you reach any decision. They are a step forward in the march of
class-D amplification into the world of organic high-end audio.
|Bel Canto Design e.One REF500 Mono
Price: $4990 USD per pair.
Warranty: Five years parts and labor.
Bel Canto Design
212 3rd Avenue North, Suite 274
Minneapolis, MN 55401
Phone: (612) 317-4550
Fax: (612) 359-9358