Classé Omega Omicron monoblock power amplifier

Non-audiophile friends and relatives raised their eyebrows when they saw the Classé Omega Omicron monoblocks. Not only is the Omicron more expensive than any other amp I've used; at 108 lbs, it's heavier than some of the speakers I've used. The Omicron is Classé's next-to-top-of-the-line amp in its Omega series, but is still definitely a "statement" product. Brian Damkroger reviewed the Omicron's big brother, the Omega Mono, in the July 2003 Stereophile. I refer you to that review for a more detailed description of the Omicron's basic circuitry.

The Omicron's considerable weight is due to the truly massive transformer in its base and the substantial heatsinking for its 48 power devices. The latter are arranged in pairs: 24 of them maintain stiff rail voltages for the 24 that actually drive the output, which is rated at 300W. The Omicron constitutes about two-thirds of an Omega in the number of its output device (24 vs 32), its rated output into 8 ohms (300W vs 500W), and its price ($10,000 vs $14,000).

The Omicron stands on its stable base as a monolithic block, one side polished black, the other brushed silver, the border between the two slashing across the top and swerving down the front panel. The black side is an integrated structural element and heatsink, while the silver side has the large but almost indistinguishable On/Off button. No connections or controls are apparent to the casual viewer.

On the front is a transilluminated omega symbol, which flashes for 10 seconds during normal initialization, and glows a soft blue when the amp is fully powered. Protection circuitry monitors current for all the internal power supplies, distortion levels, and any DC on the output. If these circuits detect anything amiss, the amp is switched into protection mode and the omega symbol glows red. I never got to see that happen, but believe me, I tried.

The Omicron's rear panel has both RCA and XLR inputs, two pairs of multiway speaker terminals, an RS-232 control port, and in/out ports for IR remote power control. At the bottom are a line fuse and a power connector that required me to use the stock power cord. Use of the RCA input requires a jumper to connect pins 1 (Ground) and 3 (Inverting input) on the XLR. The amp is shipped with the jumper already in place, but I removed it to use the balanced input. The speaker terminals are much more generously spaced and accessible than those on the Classé CAM-350 monoblock, which are crammed between that amp's sharp-edged heatsink and the floor. Connecting up the Omicron was a decidedly less painful experience!

I used two sets of AudioQuest balanced interconnects and biwire speaker cables: the same pairs I'd been using for many months, and a similar set with AQ's controversial DBS feature. Speakers were the Revel Ultima Studios and the Paradigm Studio/60 V.3s.

When I first powered up the Omicrons, I was mildly disappointed. Although they sounded somewhat similar to Classé's CAM-350s, which they replaced, my immediate impression was of a loss of upper-end zing, the Omicrons sounding warm and rolled-off in comparison. But as time passed and I listened to a wide range of music at all sorts of levels, I came to realize that my comparisons favored the Omicrons, especially in the treble.

First, however, let's dispose of the power and noise-level issues. I had no complaints about dynamics—whether on a small scale, to reveal subtle musical and emotional shadings, or on a large scale, to surprise or transport. The Omicrons were, in practical terms, the most powerful amps I've used, regardless of what the specs say, and regardless of what John Atkinson discovers on the test bench. They sounded exactly the same at all levels, from casual listening to those moments of irresponsibility when I just wanted to blast something.

When pushed very hard, other amps, in fact, most other amps, tend to sound a bit different from their normal state. The Omicron seemed almost indifferent to stress. When I indulged myself with the SACD reissue of Frederick Fennell's classic recording of Gustav Holst's First Suite in E-flat for Military Band (Telarc SACD-60639), no matter how loud I played it, the bass-drum whomps in the second and third movements were tight and tuneful. Conversely, the quiet murmurs of the opening movement sounded identically clean at a level that was only just audible, and at greater ones that revealed every creaking chair in Cleveland's Severance Hall. Neither the Omicrons nor the Revel Ultima Studios placed any limits on what I could demand—the only things that did that were the ambient noise, the tolerance of my neighbors, and my sanity.

The Omicrons' wide, deep soundstaging was also immune to changes in level. I was equally generous to a small-group jazz recording with lots of air and spacing, Oscar Peterson Meets Roy Hargrove and Ralph Moore (CD, Telarc CD-83399), and a larger, denser ensemble in a defined reverberant space: Mahler's Symphony 5, performed by Hartmut Haenchen and the Netherlands Philharmonic (CD, Pentatone PTC 5186 004). The Omicrons actually encouraged me to listen at appropriately realistic levels, never requiring me to turn the volume up or down just to experience and appreciate a particular performance's details and joys.

Transparency, too, was a hallmark of the Omicron throughout the spectrum. Bass was powerful and very well controlled with either the Revels or the Paradigms, the midrange was open and detailed, the treble clean and grainless. More significant, there was no unnatural emphasis throughout the audible range. Undoubtedly, this is one reason for my initial disappointment—the Omicron did not impress by flaunting any particular characteristic. I had to reassess those first impressions with another batch of familiar recordings.

Minoru Nojima's solo piano on Nojima Plays Liszt (LP, Reference RR-25) had the pure ping that confirms excellent transient detail, but the subtle tap of Nojima's fingernails on the ivories was not obscured. Even more critical a test is the human voice. As you might expect by now, the Omicron excelled here, too. Women's voices, such as Tierney Sutton's on Dancing in the Dark: Inspired by the Music of Frank Sinatra (SACD, Telarc SACD-83592), were absolutely pristine. However, women's voices are less of a challenge than men's, which range from the midrange down into the midbass. But from Leonard Cohen to Roy Orbison, male voices were no problem for the Omicron, which seemed absolutely seamless across the spectrum.

Was the Classé Omicron perfect? Almost. After using Classé's CAM-350 monoblocks for several months, I had came to fully agree with Brian Damkroger's assessment of them in the January 2001 Stereophile: "Putting all of the pieces together, the Classé CAM-350s had a fast, clean, precise sound. They're transparent and open, and effortlessly combine detail, dynamics, and harmonic richness across the frequency spectrum." And even though BD did most of his listening with Magnepan planar magnetic speakers and I did most of mine with the dynamic Revel Ultima Studios, I understood where he was coming from when he said, "The [CAM-350's] overall tonal balance was a little to the lean side of neutral, as if there was a slight recession or suckout in the upper bass and lower midrange. It didn't have quite the warmth and weight of other amps I tried, and could even sound a touch thin on some material." Of course, this was less of an issue with the Revels, but the flavor was detectable.

While the Omicron exhibited all the best features of the CAM-350, it did not have such a distinguishing personality. The Omicron was more evenly and fully balanced across the entire audible range, favoring no single portion of it. What it did have was a little softness at the top end that I found served it very well with most speakers (such as the Paradigm Studios) and most recordings. It was only with the few, new SACDs, or some of Reference Recordings' marvelous discs, that I noticed anything lacking. In fact, if I popped the rear-firing tweeters of my Revel Studios up just one notch, all seemed perfect. But I can muster no such complaints about the Omicrons' performance driving the new Paradigm Studio/60 v3s.

The Omicron was almost indistinguishable from my reference Sonic Frontiers Power3, except for three things: the Classé's unremitting grasp and depth of the bass, its ability to play even louder than necessary, and the need to tweak the system a bit in order to match the Power3's rendition of HF details. One way to do this, as mentioned above, was to trim the Revels' rear tweeters. Another was to choose the matching cables carefully. But these are trivial issues in this context of overall excellence.

A power amplifier should be easy: Whether on the test bench or in practical use, put a signal in, get the same signal out. Any differences, except for scaling in voltage and current, indicate a lapse from perfection. If that were all, a bench test would suffice.

In the real world, an amp must do some heavy lifting, interfacing with a source component (generally a simple task of matching impedances and levels) and transmitting the output to a speaker (generally a more complex task, considering the impedance variations of most speakers and their wide range of sensitivities). It is probably these issues of interfacing that allow us to audibly distinguish one competent power amp from another, rather than an amp's inherent amplification function.

So I wouldn't be surprised if JA gets much the same measurements from the Classé Omega Omicron as he did from the CAM-350, or even the bigger Omega Mono. They're all really good. I am nonetheless willing to posit that the Omicron is in an élite class: audibly more neutral and transparent than the CAM-350, and superior to just about anything I've heard in my system. In fact, I found it hard to quibble with in any way, save for its somewhat forgiving treble. But even that is no fault, but an issue of system matching. When I think that the Omicron's big brother, the Omega Mono, might offer even more, my mind boggles.

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