Constellation Audio Performance Centaur Mono monoblock power amplifier Page 2

The long horizontal bar on the front panel is a rocker switch with a single LED and settings of On (hold it down a while) and Mute. On the uncluttered, easily accessed, unrecessed rear panel are the three inputs, a three-way (Bal/Direct/RCA) toggle switch for selecting among them, a Mute On/Off toggle, two pairs of widely separated metal binding posts, a 15 amp IEC AC jack, and the main power rocker switch. The heatsinks are hidden behind circular cutouts in the distinctive side panels.

"Comin' At Ya" Exhilarating Sound!
I reviewed Lamm Industries' ML-3 Signature monoblocks in the September 2013 issue. Going from the luscious, softly sprung Lamms to the Centaur Monos' sports-car ride could have been jarring, even disappointing, were it not for the Constellation's spectacular transparency, transient clarity, and absolute freedom from grain, in an overall sound that otherwise seemed to favor frequencies from the midrange to the lower highs. While MOSFETs have a reputation for sounding soft, the Centaurs' mids and highs never sounded so. Nor did they sound hard or unforgiving. Instead, I could crank them up, play them at almost uncomfortably loud SPLs, and revel in the brisk sonic wind that rushed by my ears without ever worrying about getting sand in my face—unless it was the recording spraying it. The Centaur's transient performance was superclean and precise without ever straying into unnatural solid-state hardness or edge. If you prefer the saturated tonal colors of tubes, you're not likely to cotton to the Centaur's overall sound—but you will take note of what it is doing.

Peter Madnick told me that the Centaur Mono runs in class-A for the first 15W or so, and in class-A/B thereafter. Based on my experience with the darTZeel NHB 458. monoblocks' power display, chances are that the Centaur rarely, if ever, switched to A/B as it drove my sensitive Wilson Audio Specialties XLF speakers to similar levels.

The Centaur Monos hid nothing. Great recordings sounded great, bad ones had no place to hide. If you like a soft, thick, laid-back sound, the Centaurs might not be for you. But more than many I've encountered, these amps were almost empty sonic vessels, into which you could pour your choices of associated gear—and, especially, cables—to get your desired sound.

But why do that when you can use fast, open, transparent, linear gear and cables that complement the Centaur Mono's lack of self-expression? Fortuitously, dCS's Vivaldi DAC, SACD/CD transport, upsampler, and clock arrived just in time. While dCS's previous digital stack, the Scarlatti, sounded somewhat laid-back, the Vivaldis are anything but. Their openness and transparency proved an ideal match for the likeminded Centaurs, particularly when directly driven via balanced cables using the Vivaldi DAC's volume control.


Driven balanced or single-ended via darTZeel's NHB-18NS preamplifier, the Centaur's backgrounds were pitch-black. Running the Vivaldi DAC single-ended through the darTZeel didn't appreciably change the overall tonal balance, but overall dynamic expression was slightly diminished, as was transparency to a lesser degree, as happens whenever even the most transparent electronic link and associated cables are added to the chain. This slightly more laid-back sound might appeal more to some.

The Vivaldis and Centaur Monos shared what was, in my experience, an unusual ability to play at very low SPLs without apparently sacrificing any sonic performance. Both let me listen far into the music with all parameters well balanced and fully expressed (within the obvious constraint of low volume level).

Late one night I played, at almost whisper-low levels, a CD reissue of an RCA Living Stereo recording of Artur Rubinstein playing Rachmaninoff's Piano Concerto 2, with Fritz Reiner and the Chicago Symphony (JVC XRCD). I was surprised by how well the sound held up at such minuscule SPLs—that's when digital sound usually falls apart, particularly in terms of space and texture. The superb capturing of space and natural tonal balance of this recording, which was engineered by Lewis Layton, remained remarkably intact; more significant, Rubinstein's attacks were still delicate, tactile, and supple. Was that because of the dCS stack or the Centaurs? Maybe both—at low levels, my LP of this recording (RCA Living Stereo LSC-2068) was reproduced equally intact and as fully satisfying. While the sound from vinyl tends to hold up better than digital at low SPLs, this sort of low-level "togetherness" from CD was notable. As for which format sounded more real, do I really have to spell it out? Okay: v-i-n-y-l.

After cranking up the volume, I opened up the Meridian's digital music server's Core Control program on the iPad and tapped in the Records' addictive, Byrds-like "Starry Eyes," from Shades in Bed (CD, FOAMCD 5), and that brisk sonic wind blew as intensely and pleasingly as I'd anticipated. Most of this track's chimey, guitar-based action is in the upper frequencies; the Centaurs sorted it all out well spatially while keeping intact all of the aggressive, speedy, sharp transient action required to make "Starry Eyes" sail. The overdriven electric guitars rang out with generous sustain, the snare hits had great snap and control, and the insistent, finely sized cymbals rang smartly yet almost sweetly, and entirely without solid-state glaze.

The bass, however, was somewhat less fully anchored than I was expecting. Over time, it became apparent that the Centaur Mono's bass, while texturally superb, rhythmically lithe, and harmonically complete, was not, to use a word favored by my audio-review mentor, testicular when that last bit of depth-charge whomp was called for.

For instance Himmelskip, the musically mesmerizing and sonically engrossing analog recording made in a church by Norwegian organist and composer Iver Kleive and electric guitarist Knut Reiersrud (CD version, FXCD 163), can really shake a room when Kleive goes for the deep notes. The Centaur Monos' rendering of these was by no means bass shy, but it didn't produce the concentrated, gut-shaking rumble this recording can generate, and which the XLFs can mostly reproduce.

Yet the Centaurs' bass was 100% consistent with everything else it did—had it been anything other than what it was, the amp's seamlessness and superb top-to-bottom tonal, spatial, and rhythmic continuities might have been upset.

If you can play recordings with resolutions of 24-bit/96kHz or 24/192, I highly recommend Markus Schwartz and Lakou Brooklyn's Equinox (24-bit/96kHz WAV files, Soundkeeper SR1002, Stereophile's "Recording of February 2011"). Trumpeter Jean Caze and others join percussionist Schwartz in an album of lilting, driving, melodic, Haitian-based instrumental music that's guaranteed to pique your curiosity. The three-dimensional sound is as natural and artifact-free as you'll hear from any recording or medium. There's a bit more concentrated weight to be had from the drums and bass than the Centaurs delivered, but the percussion's timbral and textural resolution and detail, combined with the amps' taut rhythmic performance, more than compensated. This recording demonstrated as well as any the Centaur Monos' exceptionally pure sound, as well as their seamlessness and transparency and, especially, their ability to effortlessly project a three-dimensional soundstage.

So did the instrumental trifle "Glad," from Traffic's John Barleycorn Must Die (LP, original pink-label pressing, Island). Chris Wood's tenor sax—raucous, round, and full-throated—appeared in greater 3D relief than I can ever remember it sounding.

I switched to the Meridian's Swim mode (similar to iPod's Shuffle), and the digital gods first served up the acoustic "It's All Over Now, Baby Blue," from Bob Dylan's legendary "Royal Albert Hall" concert (actually recorded in Manchester), on Live 1966: The Bootleg Series Vol.4 (CD, Columbia/Legacy C2K 65759). If anything could spook the Centaur's somewhat forward and present midrange/lower treble, it would be Dylan's jagged, high-pitched, shouty vocal, his squealing harmonica, and the hall's reflective ambience (not to mention the raw mono recording). About 15 seconds in, my reaction to the direct, forward sound was to crank pretty loud to even louder. It only got better! Dylan's voice floated cleanly in 3D space, every vocal nuance and texture effortlessly well articulated. Even when he moved to the shrieky harmonica, the Centaur Monos' precise, natural transients produced a believable tonal and textural balance, while well behind him, the hall ambience ricocheted and decayed cleanly and naturally into a deep black backdrop to produce a notably holographic image.

Next, the Meridian swam over to Chubby Checker's cover of Hank Ballard's "The Twist," featuring the great Buddy Savitt on saxophone and an irresistible back beat courtesy drummer Ellis Tollin, which was probably as responsible as Checker's great vocal for the song's going to No.1 (CD, Parkway P-7001). This is another relatively unsophisticated recording rich in upper-midrange frequencies that, while somewhat bright, was never rough-edged or unpleasant through the Constellations, but did sound fully resolved and honestly transparent, if projected slightly and excitingly forward.

At the behest of Impex's Robert Pincus, the label reissued an RCA New Orthophonic mono recording, made in the 1950s by Jascha Heifetz and pianist Emanuel Bay, of Beethoven's Violin Sonatas 8 and 10 (LP, RCA/Impex LM-1914). Commercially, this is a risky reissue, all things considered: old, mono, just two instruments, chamber music. And while the recorded sound isn't "modern" even by 1960s standards, the honest presentation of Heifetz's violin—the sheen of the bow across the strings; the resonance of the wooden body; the well-focused, appropriately sized image; the moderate room reverb—provide a true system test. The Centaurs easily passed it, if somewhat on the dry side compared to their bipolar opposites, the comparably priced but somewhat lower-powered D'Agostino Momentums.

Play through the Centaurs your finest symphonic recordings, analog or digital, and you may conclude, as I did, that their seemingly midrange-forward sound isn't actually a coloration but a result of their transparency, transient speed, and ultraquiet backgrounds. The combination of those qualities simply makes the presentation "pop" more.

However, for its sonic greatness to truly shine, the Centaur's open-windowed sound requires careful matching of associated gear, and especially careful choice of cables.

Like examining your own complexion in a revealing light, listening to your favorite recordings and gear through power amplifiers whose sound is as uncompromised, transparent, fast, and open as that of Constellation Audio's Performance Centaur Monos might at first be uncomfortable. But rest assured, great recordings will sound great, and so will the best associated gear/

The Centaur's openness and transparency may be too much for those who prefer tube warmth, or just a more laid-back, less in-your-face sound. And you can find more concentrated and muscular bass elsewhere. If MOSFETs' reputation for softer sound emerged anywhere in what I heard from the Centaurs, it was in the bass.

If you're shopping at the rarefied altitude of $55,000, Constellation's Performance Centaur Mono and Dan D'Agostino's Momentum are two superb, very different-sounding, high-performance choices among many. Don't let any nabob of negativity tell you otherwise: This is a great time for high-performance audio.

Constellation Audio
3533 Old Conejo Road, Suite 107
Newbury Park, CA 91320
(805) 201-2610

xsipower's picture

Hello Mr. Atkinson,

I was wondering if you were told what failed on the first unit you were testing at 2 ohms. Was it a fuse? There are four small aluminum panels on the back of the amplifier when removed allow access to ATO (automotive type) fuses.

I'm also surprised the signal to noise measured so poorly. John Curl who designed the input side of the amplifier is known for his superb low noise small signal amplifier designs. See pictures of the inside of the Centaur (can be found by searching the web) they show a rats nets of wires crisscrossing around. Some of these wires come quite close to the transformer.

I understand from the article that this is a "budget" version of the flagship Hercules. It uses the same circuits, but with surface mount components and assembly done in China. Unfortunately the build quality inside the unit does not present itself as a piece of high end audio, especially at the price it's going for. I would say that the metal work of the case is amazing. They must spend a good percentage of the material cost on machining (probably done on a 5 or 6 axis machine).

I think the peaking in the high frequency response is because they do not use an output Zobel network in their design. From the picture of the amplifier module you can see that the output is directly fed from the Mosfets to the output terminals via bus bars that pass under the PCB. The output does not go through a high frequency filter (LRC network). This can make the amplifier susceptible to oscillation with capacitive loads and external ingress of RF signals.

I’m not against five or six figure amplifiers, but I am concerned with:

  1. Poor Signal to Noise for an amplifier of this price and pedigree.
  2. Input impedance way low (way out of specification).
  3. Iffy with loads less that 4 ohms ( specifications say 1000W into 2ohms)
  4. Innards build/wiring quality not up to the price being paid.
  5. Not a big deal, but it concerns me that it has a peaking response in the infra-frequencies.
  6. Probably paying a lot for the glitzy aluminum panels, rather than the meat inside.

Other than that I’m happy that Mr. Fremer enjoyed the units.


John Atkinson's picture

xsipower wrote:
I was wondering if you were told what failed on the first unit you were testing at 2 ohms. Was it a fuse?

Yes, as I write in the footnote to the measurements section in this Web reprint, Peter Madnick told me that a fuse had blown.

xsipower wrote:
I'm also surprised the signal to noise measured so poorly....

Me too, which is why I repeated the noisefloor measurement on both samples. But the noisefloor is still low enough not to be a factor in the amplifier's sound quality, I feel.

John Atkinson

Editor, Stereophile

Rick Tomaszewicz's picture

...for being so gimlet-eyed in reviewing ultra high-end gear.  This means we (the 99% - or 99.9%, as another commentor corrected me) can also rely on you for calling out underperforming affordable gear which has a more relaxed price/expectation ratio.

Perhaps your next gig should be evaluating, with the same thoroughness, large government programs prior to their launch!  

Vadim S's picture

Hello Mr. Fremer,

Thank you for the interesting reviews about some of the world's best power amplifiers.

Could you compare the Centaur monoblock performance to the performance of the Soulution 710 stereo power amplifier, at least concerning their basic sonic character? It seems like they share many qualities in common (basing on your reviews of the bespoke components).

Thank you in advance,