February 1, 2009
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TWBAS 2/2009
Speakers: Rockport Technologies Altair
Amplifiers: Arcam FMJ A38, Pass labs
X600.5, Vitus SS-101
Preamplifier: Simaudio Moon Evolution P-8
Sources: Apple MacBook running iTunes,
Stello DA220 Mk.II D/A converter, Weiss Minerva D/A converter
Cables and power conditioning: Shunyata
Research: Aurora-IC interconnects, Aurora-SP speaker cables, Hydra V-Ray power
conditioner; Anaconda Helix Alpha/VX, Python Helix Alpha/VX, Taipan Helix Alpha/VX power
cords |
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Rock-Solid Power: Classé
Audio Omega Omicron Mono Amplifiers
Albert Einstein said, "Everything should be
made as simple as possible, but no simpler." But in audio, is simpler always
better? Its the "as possible" that sometimes gets missed. In the world of
audio design, its commonly accepted that a circuit design should be simple --
as in adding no unneeded complexity that could compromise sound quality. But what if a bit
more complexity is needed to make the product sound better? Classé Audio would
likely argue that the power supplies theyve designed for their Omega power
amplifiers are more complex, and thus more costly, than those in their Delta range.
Theyd also tell you that that complexity is precisely whats needed to improve
the sound of their top-of-the-line amps.
The Omega Omicron Mono amplifier ($25,000 USD per pair),
introduced in 2003, is Classé Audios second most expensive product, and benefited
from the development of the larger, even costlier Omega Mono ($35,000/pair) of a few years
earlier. According to Dave Nauber, executive vice president of Classé Audio, the Omega
Omicron Monos "basic topology is the same, but the boards and parts benefit
from more recent tweaking" than the Omega Mono has been subjected to. So when I was
considering the Classé range for evaluation, the Omega Omicron Mono, which puts out 300W
into 8 ohms, made the most sense to audition in "The Worlds Best Audio
System": my speakers, the Rockport Technologies Altairs, are claimed to have a
sensitivity of 90dB/W/m and an impedance of 4 ohms. On paper, therefore, the Omega Omicron
Monos offered what appeared to be plenty of power. And if they might sound even better
than the larger, more expensive Omega Monos . . . well, it was off to the races.
Some hardware facts
Classés Omega components are shipped in metal flight
cases that are far more costly but far more durable than mere cardboard cartons. Such
packing befits a luxury product, and gives one a sense of pride of ownership even before
the actual amplifiers have emerged. The Omega Omicron Mono is large but not unmanageable.
Though at 108 pounds its very heavy for its dimensions of 16.5"H x 10"W x
19.5"D -- meaning its insides must be stuffed tight with parts -- each Omicrons
unpacked bulk can still be maneuvered into place by one person. When Id considered
the Omicrons fitnfinish and overall appearance once Id placed them
in my room, I sat down impressed, anxious to hear them. A large-format owners manual
and custom power cords are included.
These babies should have no problem driving the toughest
loudspeakers around -- each Omicron Mono is rated to deliver 300W into 8 ohms, 600W into 4
ohms, or 1200W into 2 ohms. This impressive power output is supported by an equally
impressive power supply: each chassis contains a 1620VA toroidal power transformer and 48
filter capacitors totaling 201,600 microfarads.
The output stage of the class-A/AB Omicron is where things
get really interesting. In most solid-state amplifiers, a bank of output devices -- the
parts that actually deliver power to your speakers -- is regulated by capacitors, which
are passive devices. Either a bank of many small capacitors, or a few large units the size
of soda cans, provide a source of voltage to keep the output devices operating in a linear
fashion. The problem with this approach is that capacitors must recharge constantly after
being discharged into the output devices. When the musical demand is heavy, the cycle of
charge and discharge can negatively affect the amplifiers output stage: the voltage
drops, and the heart of the amplifier itself can become starved for power.
However, the Omicron Monos output stage is not
regulated by passive capacitors. Instead, each of the 24 bipolar output transistors has a
dedicated regulator that actively supplies it voltage from another, identical bipolar
transistor. So instead of a bank of 24 output devices, each Omega Omicron Mono has 48
such devices -- the 24 that comprise the output stage, and another 24 that regulate the
first set. Together these act as a rock-solid amplifying circuit that should have only
minute voltage drop, even under the most demanding conditions. What this should mean in
the real world is that the amplifier wont get stressed when faced with huge dynamic
swings caused by demanding musical passages.
Other aspects of the Omega Omicron Monos are impressive as
well. Classé describes the circuit as being fully balanced from input to output. The
chassis itself reverses the usual amplifier shape of being wider than it is tall -- not
unlike the flagship models from Halcro and Mark Levinson. The quality of the casework is
impeccable: the front, top, and sides show no evidence of screws or any form of fastening
hardware. The heatsinks are routed out of a solid slab of aluminum on only one side of
each chassis, the other side being smooth. This, to me, seems a far better design for
heatsinking a component -- there are no sharp edges, and, when tapped, there is absolutely
no ringing to be heard.
See the entire Classé Audio Omega Omicron
gallery by Chris Lang.
Sound
The sound of Classés Omega Omicron Monos jumped out
at me from the moment I powered up my system after installing them. Now, immediately
noting a components sonic character can be a good or a bad thing. Often, a component
that is satisfying in the long run produces sound that at first is somewhat boring; such
is the nature of neutrality. The distinctive sound of the Omicrons, however, was a
departure from what Id just been listening to. I was finishing up my auditioning of
the modestly priced and powered Arcam FMJ A38 stereo amplifier ($2300, 100Wpc) -- a
good-sounding design, but no competition for some of the behemoth solid-state amps
Ive had in my system over the last couple of years. Boy, was I shocked when the
first note from the acoustic guitar and close-miked voice of Jakob Dylan poured forth from
his Seeing Things (CD, Sony 702328). They were right there -- close and
intimate, almost making me move my head back in my seat a few inches.
The FMJ A38 is fairly neutral; I could briefly describe it
as "smooth but nondescript." In comparison, the Omicrons lit up the room. What
stood out first was the midrange -- it was just different. Male voices, in
particular, were rendered with more body -- that sense that the men were physically
present in the room because the physical outlines of their bodies were more distinct and
filled with living, breathing humanity. The sense of palpability was startling. How the
Omicrons accomplished this was interesting. First, it seemed that the midrange was a bit
more forward than Im used to hearing. Artists such as Jason Mraz seemed placed
closer to my listening seat than Im used to hearing them. Mrazs voice on
"Mr. Curiosity," from his Mr. A-Z (CD, Elektra 83833), sounded natural
but forward. But being a touch up-front wasnt all that was going on. There was also
more information within the outline of the performer. I could hear deep into Mrazs
voice without any sense of strain or fatigue. I could also "see" Mraz
more clearly in my room. It took me only an hour or so to get used to this quality; soon,
it sounded totally natural. In fact, when I flipped back to the Arcam A38 for a quick
refresher before boxing it up to send back, it sounded recessed and too laid-back, almost
muted, in the midrange.
The Omega Omicron Monos soundstaging qualities were
complemented by the greater physical presence they gave performers. Not only was there
simply stunning separation between instrumentalists and vocalists, but the width and depth
on the stages on which the musicians were set were expanded as well. These amplifiers
should augment a good set of loudspeakers by not truncating the sense of space, whether
natural or studio-created, between musicians. In fact, they should expand on these
qualities, giving the sounds of the musicians more room to breathe -- the Omicrons created
realistically sized spaces that had me "watching" as much as listening to the
performances. Fascinated by this aspect of their sound, I found myself scrolling through
my music collection, looking for tracks that would allow me to hear greater
dimensionality. An example is David-Lloyd Jones conducting the Royal Scottish National
Orchestra in Holsts The Planets (CD, Naxos 8.555776). I might as well have
been watching Raphael Nadal and Roger Federer, such was the interplay between right and
left and front to back.
Normally this is the part of the article where I would go
through my checklist of important sonic characteristics, but the Omega Omicron Monos were
sufficiently neutral as to not warrant that type of description. The frequency extremes
were simply excellent -- the bass was solid and deep, the highs extended and detailed.
Tonality was spot on, and there was no sense of a lack of power -- in fact, the Omicrons
seemed to have more reserve than just about any amplifier Ive had in the Music
Vault. But this doesnt mean that the Omicron Monos sounded like all the other
solid-state Ive recently heard -- to the contrary.
I normally get lots of e-mail asking how the various
amplifiers Ive heard stack up against each other. Heres a
quickndirty selection of the most relevant comparisons:
Omega Omicron Mono vs. Vitus SS-101: The Vitus
amplifier was just as quiet as the Classés, and both were about as good as Ive
heard in this regard. The Vitus, though, was more laid-back, while the Classés sounded
more immediate. Voices were somewhat more relaxed through the Vitus, and sonic landscapes
were rendered in a more evenhanded manner. Performers seemed a touch farther back on the
stage, and just slightly smaller, through the SS-101. This wasnt a night-and-day
difference, but I could understand if different listeners preferred one sort of sound to
the other enough to sway a purchasing decision.
Omega Omicron Mono vs. Pass Labs
X600.5: This was a fascinating comparison. The Pass and Classé amplifiers are both so
darn good that Im almost embarrassed to call either of them "weaker" in
any area -- theyre both simply great. But theyre not the same. The Pass
Labs arent as quiet as the Classés. I definitely got a sense of
"blackness" with the Omicrons that the Passes just couldnt muster. On the
other hand, the Pass amps had an unrestrained quality -- as if they were letting go of the
notes more easily -- that was somehow missing from the Classés. It was if the Passes just
let the signal flow with no resistance at all. The Omega Omicrons propelled things along a
bit by comparison. The Classés moved ahead of the Passes in the ability to separate
performers within the soundstage, and there is no doubt that their midrange presentation
was more energetic and more full of information. I could easily live with either amplifier
-- both are fantastic, and among the worlds best amplifier designs.
Conclusion
The Classé Audio Omega Omicron Mono is not the newest
high-end amplifier design out there. But when it comes to power amplifiers, not many of
the very newest designs have lit my fire. Sure, theres a bevy of class-D, class-T,
and class- . . . well, you name the class, and these days there are a lot of power
amplifiers to choose from. And its easy to understand why a company would make a
digital-switching product when such a choice can reduce the cost of everything, from parts
to labor to shipping. And if these small-fry switching amps were sonically better than the
larger "old school" designs, all would be right in the world -- or at least the
worlds amplifying corners. But when I listen to Classé Audios Omega Omicron
Monos, Im reminded again of what Einstein said: "Everything should be made as
simple as possible, but no simpler." It occurs to me that, as far as power-amp
perfection goes, maybe a design as complex as the Omicrons is as simply built
as possible.
It could be that were just around the corner from
smaller, lighter, easier-to-manage amplifiers that will blow away the Omega Omicron Monos,
but I wouldnt put my money on it. My guess is that, to many audiophiles, and to the
companies that make amplifiers, the advantages of smaller size and greater efficiency
along with lower prices are acceptable even if sound quality suffers. And thats OK
with me, too. But if you want the best sound that transistors can produce, you just
better go out and invest in some Classé Omega Omicron Monos before their ilk disappears
altogether.
. . . Jeff Fritz
jeff@ultraaudio.com
Manufacturer contact information:
Classé Audio, Inc.
5070 François Cusson
Lachine, Québec H8T 1B3
Canada
Phone: (514) 636-6384
Fax: (514) 636-1428
E-mail: cservice@classeaudio.com
Website: www.classeaudio.com
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