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- Written by Doug Schneider Doug Schneider
- Category: Full-Length Equipment Reviews Full-Length Equipment Reviews
- Created: 15 December 2017 15 December 2017
Note: Measurements can be found through this link.
In the 22 years of the SoundStage! Network, I’ve reviewed audio products of all shapes, sizes, and types -- but I’ve tended to shy away from items that cost as much as or more than the average car (these days, in the US, that’s just under $35,000). If an audio product costs more than that, two questions inevitably pop to mind: 1) Who can afford it? and 2) Why in the world does it cost that much? That’s why, on SoundStage! Hi-Fi, in all these years, you’ll find few such components reviewed under my byline.
Despite the price bias, I’m not oblivious to the fact that many audio products exceed my cost threshold, or, more important, that I’m not serving those readers who are willing to spend that much. As a result, I won’t completely shut my listening-room door when asked to review such expensive stuff, particularly if manufacturers who want to send those products know where I stand on high prices.
Enter Constellation Audio, who offered to send me their Revelation Pictor preamplifier ($18,000 USD) with optional DC filter ($5000), as well as the subject of this review: a pair of Revelation Taurus Mono monoblock amplifiers ($19,500 each). At $39,000, a pair of Revelation Taurus Monos cost $4000 more than that average-price car. Could their sound convince me that they’re worth it?
Constellation Audio makes four series of electronics -- ascending in price from entry level, they are the Inspiration, Revelation, Performance, and Reference lines. The models in each are cut from the same technical and visual cloths.
All Constellation amplifiers are based on the same 125W amp-module design, which, instead of the usual combination of N- and P-type transistors, uses only N-type transistors for the positive and negative halves of the signal, in a topology Constellation calls Balanced Bridged. As the power outputs of Constellation amp models increase -- that is, from a stereo model to a monoblock within a series, or from one series to the next higher -- more and more of these modules are typically used, and the power supplies to support them usually get more elaborate.
When Constellation designed its very first amplifiers they settled on a specific type of transistor they wanted to use; however, only N-type devices were available. Nonetheless, they decided to go ahead, and figured out a way to design the amp using only N-types. That design constraint proved fortunate -- because the transistors used to amplify both halves of the signal were identical, those halves ended up being perfectly symmetrical, which apparently isn’t always the case in amps that use both N and P transistors. Constellation liked the results so much that, ever since, every Constellation amp uses only N-type transistors.
Another design element common to all Constellation Audio amps is the Constellation Direct input, an XLR-type balanced connection designed to be used with a Constellation preamplifier, all of which have higher-than-normal gain (about 25dB), and is how I connected the Pictor to the Tauruses. With this connection, an entire gain stage of the amplifier is bypassed, for a purer signal path. For compatibility with conventional preamplifiers with lower gain there are still the usual balanced (XLR) and single-ended (RCA) inputs. These are internally connected to the Line Stage Gain Module, which provides enough gain (how much isn’t specified) to drive the amp’s output section. A small toggle switch on the rear panel lets you choose between these inputs.
The Revelation Taurus Mono is specified to output up to 500W into 8 ohms or 1000W into 4 ohms. Each amp measures 17”W x 8.25”H x 21.5”D, excluding binding posts and feet, and weighs 120 pounds. In their promotional copy Constellation repeatedly points out that the Taurus Mono is smaller and lighter than the model of monoblock immediately above it, the Performance Centaur II Mono ($40,000 each), which measures 18.75”W x 11.5”H x 24.25”D and weighs 130 pounds. (The Centaur II Stereo also costs $40,000.) The Taurus Mono is not small -- the pair of them took up eight square feet of my floor, which is where I suspect most buyers will put these heavy beasts. No shelves of my equipment rack were big or sturdy enough. Constellation says that the Taurus Mono weighs almost as much the Centaur II Mono because they have nearly identical power supplies.
Here’s what happens when you move down through Constellation Audio’s product line: The Revelation Taurus Stereo and a single Revelation Taurus Mono each cost $19,500, the Stereo delivering precisely half the Mono’s power output per channel: 250Wpc into 8 ohms or 500Wpc into 4 ohms. The Inspiration Mono 1.0, the sole monaural amplifier in Constellation’s lowest-priced level, costs $11,000 and delivers 400W into 8 ohms or 800W into 4 ohms. The Inspiration Stereo 1.0 costs the same and delivers 200 or 400Wpc into 8 or 4 ohms.
While all Constellation amps share the same basic company look, the Revelation Taurus Mono and Stereo, and the Inspiration Mono 1.0 and Stereo 1.0, are all pretty much cosmetically identical, save for small differences on their rear panels and in their overall depths. All share the same heavy-duty, thick-walled aluminum case -- it’s attractive and, rapped with a knuckle, responded not with a bell-like ring but a dull thunk. The Taurus Monos felt satisfyingly inert. The whitish-gray finish has a texture that feels like suede. It feels and looks great.
Each amplifier side comprises two aluminum panels finished in the same whitish-gray, both with large holes cut throughout and slightly offset with each other. This offset produces an interesting-looking design, and provides ample ventilation. Low on the front panel is the horizontal bar found on all Constellation power amps. Press the left side of this bar for about three seconds to toggle the amp between Standby and On -- it then takes about 30 seconds to warm up. Pressed momentarily, the left side of the bar mutes the amp’s output. On the rear are two pairs of heavy-duty speaker binding posts, a white rocker switch to power the amp fully off or on, RS-232 and USB connectors for use with home-automation systems, and a 1/8” trigger input for remote turn-on from another device.
I also like the two ridges that begin at the bottom of the front panel, just to the left and right of the bar, go straight up to the case’s top front edge, steadily increasing in relief, then continue across the top panel, decreasing in height from front to back until they disappear into the top panel’s surface just before the amp’s rear edge. And the proportions of the Revelation amps are more pleasing to my eye than Constellation’s more expensive models, which are much more tall and bulky.
I have a nit to pick. Although the metalwork of the review samples I received seemed good, the seam tolerances weren’t up to the standards of the best-made amps. And inside, the wiring didn’t look as tidy as it might have. Granted, all that is never seen by the user, and might have no effect on sound or reliability -- the Taurus Monos worked perfectly the many months they were here -- but in products that cost as much as these do, I think that the level of fit’n’finish could have been a bit higher.
I did most of my listening with the Revelation Pictor preamplifier and its external DC filter, connected to the Revelation Taurus Monos with Audience Au24 SX balanced interconnects. Wanting to test the standard XLR input as well (I seldom use single-ended connections anymore, so I didn’t test that), I also used the amps with a Simaudio Moon Evolution 740P preamplifier and a Hegel Music Systems HD30 DAC, whose digital volume control allows it to be used as a preamp when directly connected to power amps. The Simaudio and Hegel were connected to the amps with the same Audience Au24 SX interconnects I used with the Pictor, and both were able to drive the amps capably. The sound of the entire system was similar with all three, with some subtle differences described below.
Other equipment included a Samsung laptop computer running Windows 10, Roon, and Tidal connected with an AudioQuest Diamond USB cable; and an EMM Labs DA2 Reference DAC with the Constellation and Simaudio preamps, connected via Crystal Cable Standard Diamond balanced interconnects (but not when I was using the Hegel DAC); and three pairs of loudspeakers, wired to the amps with Siltech Classic Anniversary 330L cables: GoldenEar Technology Triton References, Dynaudio Special Fortys (review forthcoming in January 2018), and Revel Ultima2 Salon2s. Being able to use multiple speakers allowed me to better judge the Taurus Monos’ compatibility with differing designs as well as their overall sound quality -- I could hear which characteristics of their sound remained consistent from speaker to speaker to speaker.
The Constellation Revelation Pictor and Revelation Taurus Monos had been played before I received them, and had had a battery of measurements taken by Bascom H. King, so little break-in was needed. Still, I used them for casual background listening for a week or so before doing what most people do when they get a pair of high-powered monoblocks: crank them as loud as the speakers I was playing could go without damage, to see if they’d run out of juice, and to find out what they sounded like on the way there.
Although GoldenEar’s Triton Reference is a large, three-way floorstanding speaker with six drivers (one tweeter, two midranges, three woofers) and four passive radiators, its moderate impedance, built-in bass amp, and high sensitivity of more than 91dB/W/m make it a snap to drive. Extremely high and clean-sounding sound-pressure levels (SPLs) were a cinch to achieve from the Tauruses with these speakers -- the amps seemed to be hardly working; I’m sure the speakers would have given up long before the amps. At about 86dB/W/m, Dynaudio’s Special Forty isn’t nearly as sensitive as the Triton Reference, but it’s only a small two-way. Although the Dynaudios needed much more juice to be able to sing at SPLs comparable to what I got with the GoldenEars (each 3dB increase in SPL requires a doubling of amplifier power), the amount of power needed was still a fraction of what the Tauruses could provide. Power-wise -- overkill again. Even the Revelation Taurus Stereo, with half the output per channel, would likely provide more power than either of these speakers needs.
Revel’s Salon2 was a different story -- this four-way, six-driver, fully passive floorstander is of low sensitivity (about 85dB/W/m) and presents a somewhat difficult load: 6 ohms overall, but around 4 ohms from 500Hz down, with a 3.7-ohm minimum. Most tube amps don’t work well with the Salon2 -- few have enough muscle to exert full control over the speaker’s woofers. Solid-state amps that deliver 100Wpc into 8 ohms can work with a pair of Salon2s up to moderate volume levels, but I believe that 200Wpc is the least an amp needs with dynamic music if it’s to avoid clipping, and 400Wpc or more is better if you want to experience all that these speakers can do in terms of output and bass.
All of which meant that the 500W each Taurus Mono could provide wasn’t excessive -- they produced SPLs as high as I’ve ever experienced with the Salon2s, with utterly clean, effortless sound throughout the audioband with every type of music I played. Sometimes amps sound coarse or strident in the highs when the going gets tough. For example, Simaudio’s Moon Evolution 870A ($22,000), specced to pump out 300Wpc into 8 ohms in stereo or 1200W in bridged mono, sounded very clear at most volume levels, but less refined in the highs at very high powers. But nothing made the Taurus Monos ever sound less refined -- the sound was exceedingly loud and reverberating throughout the room, but still clean at the top. The Salon2’s bass can get blurry and undefined if an amp doesn’t control its three woofers well, but with the Taurus Monos in charge, the bass was as deep and tight as I’ve heard from these speakers -- no overhang, no blurring, no lack of weight. They held the Revels in an iron grip.
“Drawn to the Blood (Sufjan Stevens Remix),” from Sufjan Stevens’s The Greatest Gift (16-bit/44.1kHz FLAC, Asthmatic Kitty/Tidal), had bass of tremendous weight that went so low that I could feel and hear it. The propulsive kickdrum that underpins the title track of Adam Cohen’s We Go Home (16/44.1 FLAC, Cooking Vinyl/Tidal) was supertight and visceral, and made me want to stamp my feet to the beat.
The high-volume pyrotechnics out of the way, I began to hear qualities in the Taurus Monos’ sound that impressed me even more. Not that high power output isn’t impressive -- it’s just that it’s not that often that all that much of it is required. If you’re going to live with an amp(s) for the long term, it must sound great at every level you listen to.
We say that an audio product has a higher resolution of sound if it can reveal more detail than other audio products. The greater the resolution of sonic details, the more of the music you hear and the richer your experience of its nuances. The definition of smooth isn’t as cut and dried, though the term is often used by audio reviewers. For me, a product’s or system’s reproduction of music sounds smooth when it’s free of such artifacts as distortion and noise, so music flows into your ears in a more pleasing way. Think of a smooth drink -- it goes down easy. Pure might be another word to describe this. Regardless, I’ve heard many amps that exhibit varying degrees of detail and smoothness -- tube amps often excel at smoothness, while solid-state is known for detail -- but it’s rare to have both in abundance in the same amp, and with no drawbacks. Simaudio’s Moon Evolution 870A had a good balance of smoothness and detail, but it wasn’t the pinnacle of either -- other amps I’ve had here sounded smoother and/or more detailed. The last I heard that hit that high mark was Luxman’s M-900u ($20,000), a 150Wpc stereo amp that I reviewed in April 2015; in fact, the Revelation Taurus Monos’ sound reminded me of the M-900u’s, which I wished I still had here to compare directly.
I first heard how detailed and smooth the Tauruses could sound when I played “You Will Become,” from Glen Hansard’s Rhythm and Repose (16/44.1 FLAC, Epitaph/Anti-/Tidal), through the Triton References, with Constellation’s Pictor preamplifier. Although the listening level was very low, details sprang to life in a way that startled me for how apparent they were amid the “blackest” of aural backgrounds. The tonal balance across the audioband was spot on -- everything sounded real and natural. I also heard a well-fleshed-out soundstage with first-rate width and a more than credible sense of depth. I didn’t have to concentrate hard to visualize it -- the acoustic space was simply there. Hansard’s voice was palpably front and center, reproduced very smoothly but still with loads of detail, the air directly around his head seeming to hover like a fog of sound. I’d never heard the Triton References image with this precision before, or have them re-create such a well-defined sense of space.
“Spanish Steps,” from Van Morrison’s Poetic Champions Compose (16/44.1 FLAC, Mercury/Tidal), struck me in the same uncanny way -- great soundstage width and depth, razor-sharp delineation of instruments on the stage, and so much air in the room that it seemed as if I could see a mist. Then there was Morrison’s alto saxophone -- every nuance revealed, but rendered in the most realistic, most natural-sounding way, with faultless timbral accuracy. I heard detail and smoothness in spades. It all added up to a wholly natural sound that revealed itself in every other recording I played.
When I played these tracks and others through the Dynaudio Special Fortys, I lost the bottom octave of the audioband -- after all, any small two-way stand-mount design such as the Forty has bass limitations that even super-powerful amps can’t overcome. When the bass comes on strong midway through Hansard’s “You Will Become,” it sounded stunted. But the smoothness was still there, and the detail through the midrange was even a bit greater -- a strong suit of this speaker. I also found that the Taurus Monos’ way of conveying space became even more distinct, probably because of that increased detail.
Although the Revelation Taurus Monos’ high power was far more than the Dynaudios needed, as I was already reviewing them, I used the Taurus Monos for them anyway because of how well they controlled the speakers’ drivers, particularly the woofers, and how much detail they could provide. I felt as if I was giving the Fortys their best chance to shine -- which they did, with hi-rez sound very transparent to what was on the recordings (save for the low bass). When that review is published, you’ll read that I describe the Forty as being one of the most neutral two-ways Dynaudio has ever made. I felt confident coming to that conclusion because I knew that the amps were contributing no colorations of their own, which makes them a great reviewing tool for speakers.
The Special Fortys were also the speakers with which I mainly played around with the Constellation Pictor, Simaudio 740P, and Hegel HD30, to hear whatever sonic differences I could among the three. Those differences were small. Their smoothnesses throughout the audioband were comparable, but the Pictor sounded ever so slightly more detailed than the 740P, which I believe is why its sound was also more spacious, with greater tangibility of musical images. (Remember, both of these preamps were used with the EMM Labs DA2 Reference DAC.) The Hegel HD30 sounded as detailed as the combo of DA2 Reference and Pictor, but a bit more incisive -- the visceral sound Hegel products are known for came to life here. Still, the EMM-Pictor combination sounded more spacious than the HD30, though these differences weren’t that significant -- overall, the character of the Taurus Monos’ sound didn’t change much. Although I think the Taurus Monos’ best synergy was with the Pictor, there’s no reason you couldn’t use another company’s high-end preamp.
Mating the Pictor and Taurus Monos to the Revel Salon2s brought back the bass lost with the Dynaudio Fortys, while retaining all the detail I’d heard before. The Salon2s also had something the other speakers didn’t: far better dynamics, even at modest listening levels. Everything felt freer, the amplifiers sounding even more alive and open than with the other speakers. The reproduction of “No Landing (Lucknow),” from Greg Keelor’s Gone (16/44.1 FLAC, WEA/Tidal), was something of a revelation for how exciting it was to listen to. His voice, at center stage, sounds as if very little postproduction processing was applied to it -- it sounds very naturally recorded -- and it soared effortlessly and freely, completely unrestrained. The acoustic space was once again reproduced very obviously around him. And I noticed something else: Although the soundstage on this track wasn’t any deeper than I’d heard it portrayed before, it seemed to widen toward the rear -- Anne Bourne’s cello at far left, Francis Anil’s guitar at far right. The Constellations also let me hear the positioning of Parijata Charbonneau’s tablas better than I’d previously experienced -- they were farther back on the stage, the larger drum producing the lower frequencies on the left, the smaller one on the right.
Further exploring soundstaging with the Revel Salon2s, I turned to two albums I’ve used for decades to evaluate equipment, played from files ripped to my computer: the Cowboy Junkies’ The Trinity Session (16/44.1 FLAC, RCA) and Ennio Morricone’s score for the film The Mission (16/44.1 FLAC, Virgin). That each was recorded in a large venue is readily audible in every track. It wasn’t only that the soundstages were huge and exceedingly well defined -- they also seemed, again, wider, all the way to the back. It was as if everything had opened up a bit without losing the specificity of any voice or instrument on each stage. My first thought was that this was being helped by the fact that these were monoblocks, with which absolute channel separation is possible -- but I’ve regularly used JE Audio VM60 monoblocks ($6600/pair), and I used to own Anthem Statement M1 monos ($7000/pair), and their stages were never this wide. My other hunch is that the Revelation Taurus Monos’ exceptional retrieval of detail let me hear more. I can’t be sure why, but that doesn’t matter as much as that it was consistent in what I heard.
Playing these two longtime reference recordings sent me down a rabbit hole. When I listened to The Trinity Session yet again, I was struck by how natural Margo Timmins’s voice sounded, and by all the air I could hear around it -- a small but significant increase in resolution and clarity from what I’d heard with other amps. In The Mission, the sound of the woodwind instruments grabbed my attention -- a breathy quality I hadn’t noticed before that made them sound more real, with a bit more presence. After having heard both recordings so many times over the years, I was surprised to hear something new. Which makes me think that while I’ve already spent several thousand words describing these amps, there may be still more to say about them -- a telltale indication of a great hi-fi product.
I’d like to see Constellation Audio’s Revelation Taurus Mono built to a slightly higher quality, to fully justify its high price. But I wouldn’t change a thing about its appearance, which I liked -- or its sound, which I loved. Powerful, smooth, detailed -- you name it, the Taurus Monos took hold of the three pairs of speakers I used them with and made them sound their best. I can’t imagine any speakers they wouldn’t work well with. If someone has the means and the desire to spend on these amps more than most people would spend on a new car, I wouldn’t try to talk them out of it. They’ll likely find the sound worth every penny.
. . . Doug Schneider
- Speakers -- Dynaudio Special Forty, GoldenEar Technology Triton Reference, Revel Ultima2 Salon2
- Preamplifier -- Constellation Audio Revelation Pictor, Simaudio Moon Evolution 740P
- Power amplifiers -- Blue Circle Audio BC204, JE Audio VM60 (monoblocks)
- Digital-to-analog converters -- EMM Labs DA2 Reference, Hegel Music Systems HD30
- Computer -- Samsung laptop running Windows 10, JRiver Media Center 20, Roon, Tidal
- Digital interconnect -- AudioQuest Diamond USB
- Analog interconnects -- Audience Au24 SX, Crystal Cable CrystalConnect Standard Diamond
- Speaker cables -- Siltech Classic Anniversary 330L
- Power cords -- Shunyata Research Venom HC
- Power distributor/conditioner -- Shunyata Research Venom PS8 with Defender (2)
Constellation Audio Revelation Taurus Mono Amplifiers
Price: $39,000 USD per pair.
Warranty: Three years parts and labor.
Suite 1, Level 6
580 St Kilda Road
Melbourne Vic 3004
3533 Old Conejo Road, Suite 107
Newbury Park, CA 91320
Phone: (805) 201-2610