Pre/Power Amplifiers

Californian amplifier specialist Constellation Audio isn’t one to regularly refresh its product catalogue, so when – after years of maintaining the same models – it begins a complete overhaul of its entire range, audiophile ears prick up. First to hit the market are the new Inspiration 2 and Revelation 2 series, with the latter’s stereo pre/power system being debuted at the UK Hi-Fi Show Live 2024. These will be followed by the Performance 2 and Reference 2 [see boxout], with the lineup then topped off by the flagship Statement amps first ‘teased’ in 2023 at the Munich High End show.

There’s a clear hierarchy to these series, and the Revelation 2, like its predecessor, is intended as the ‘strategic link’ between Constellation’s entry-level Inspiration hardware and its costlier models. To that end, the Revelation 2 Stereo Amplifier sells for £35,000, while the Revelation 2 Preamplifier is £29,998. There’s also a new £33,998 Revelation Phono Preamplifier, with flexible loading options for MC and MM pick-ups, plus the Revelation 2 Mono amplifier at £35,000 a piece. Not pocket change prices, then, but not quite as vertiginous as that of Constellation’s step-up Performance 2, where the incoming Stereo 500 amplifier, which is the successor to the Centaur II 500 Stereo [HFN Sep ’19], will set you back £97,998.

Above: The Revelation 2 Stereo power amp – pressing the left side of the bar on the fascia for three seconds on initiates a series of self- diagnostic checks

Time to switch

What’s spurred this all-new product line? As the manufacturer puts it, a ‘need to push beyond traditional designs and embrace innovation’ – and that means a wholesale transition from linear power supplies to custom switchmode designs. The result is the new Constellation Switch Mode Power Supply (C-SMPS), fine-tuned over a five-year R&D period in partnership with a third-party specialist. Two C-SMPS modules reside inside the Revelation 2 Stereo in a separate enclosure [see pic, below], and are clearly not ‘off-the-shelf’ solutions.

Constellation says its modules ‘increase in sophistication, rectification and parts used’ as you move up through its new hardware ranges. Advantages over transformer-based linear power supplies – high frequency switching noise notwithstanding – include universal AC mains voltage selection, reduced shipping weight (and cost), improved efficiency and, potentially, reduced build costs. Hand in hand with this is Constellation’s Power Factor Correction (PFC) circuitry, ahead of the C-SMPS, to maintain stability regardless of AC voltage.

Yet, as PM reveals [see boxout], the move away from linear PSUs hasn’t resulted in Constellation throwing the baby out with the bathwater...

Above: The Revelation 2 Stereo's dual mono layout sees two custom switchmode PSUs [left, top and bottom] feeding the J-FET (balanced) input and separate N-channel MOSFET-based power modules

Powering up

As is the case with the company’s earlier amplifiers, the Revelation 2 employs N-channel power MOSFETs in its balanced output stage plus a J-FET-based line-level gain stage that can be bypassed, if desired, by connecting a preamp to the XLR inputs marked ‘Direct’. Also like its previous amplifiers, the Revelation 2 claims a power commensurate with the price: 2x300W/8ohm and 2x600W/4ohm. For those keeping count, that’s 50W-per-channel more than the first-generation Taurus Stereo [HFN Dec ’17], even while this new amplifier manages to be marginally more ‘manageable’ in terms of size, and less than half the weight at 25kg compared to 54kg.

Otherwise, the progression to series 2 has yielded little change to the external design, apart from switching the natural aluminium chassis finish to a champagne gold colourway. The austere look of the Revelation 2 Stereo, where the front panel is blank save for a long power/mute button with colour-changing status LED, carries on a now-familiar aesthetic that Constellation says will ‘please the eye, but never distract the eye’. And yes, I’d agree with the second part of that, while suggesting that many other amplifiers at this premium level offer more when it comes to ‘pride of ownership’. But beauty is in the eye of the beholder.

The stablemate Revelation 2 Preamplifier gets the same champagne gold finish for its full-width chassis, which measures 381mm deep and is therefore amenable to placement on a standard hi-fi rack. This comes with its own, external power supply chassis, to fully isolate its C-SMPS circuitry from the preamp electronics. The two units make for a neat, stacked install, and are laced together by three umbilicals, with multi-pin connectors, into sockets marked left, right and control. USB-B and RS-232 ports on the back of both amplifiers then facilitate their use with automated control systems, while 12V triggers are provided for a more basic form of communication between the two enclosures.

Above: Inside the Revelation 2 preamp the large PCB hosts Constellation’s fully balanced, FET-based line stage. The outboard PSU feeds the left/ right channels, and the control circuits

Screen test

If I had to pick an aspect where this pre/power system could be more refined it would be the preamplifier’s display. There’s nothing particularly wrong with this, but the method of control – small, physical keys underneath and some touch-sensitive areas on the LCD screen itself – is a bit fiddly. When a manual must go into considerable detail to explain how to achieve what should be a basic adjustment, it’s a clue that more polish is required. Still, you might not make much use of the preamp’s screen/buttons anyway, as apart from displaying volume and source, functions are limited to setting maximum and minimum volume levels, instigating the amp’s Home Theatre Bypass mode for a specific input, and changing the brightness, contrast and time-out settings of the screen itself. Balance, phase and source selection can also be set here, but are also offered by the preamp’s (champagne gold!) remote.

Slam dunk
Calling your pre/power system Revelation is a bold move, but Constellation’s second-generation pairing lives up to its name with the kind of performance that separates the merely ‘good’ from the truly ‘great’. Used with several different loudspeakers in the HFN listening room, including B&W’s 801 D4 Signatures [HFN Sep ’23], Parker Trio floorstanders from Marten, and the special ‘fx’ version of Wilson Audio’s Alexx Vs [HFN Jan ’22], these amplifiers seemed to get the best from all of them. There is no single trait that leaps out of the Revelation 2’s performance, just a fine blend of hi-fi’s sought-after attributes, by which I mean depth, slam, detail, openness and rich tonality. Tracks you might have heard countless times before sound fresh and exciting.

Rock Rediscovered

As an example, listening to AC/DC’s ‘Ride On’ [Dirty Deeds Done Dirt Cheap, Columbia; 96kHz/24-bit] focused my attention on elements that, at other times, seem to get washed over, such as the lean tone of Angus Young’s guitar in the bridge, the layers of grit to Bon Scott’s vocal, or the faintest of backing chants in the chorus. It was as if I could almost hear the tubes of the guitar amp thrumming away during the one-and-done improvised solo, such was the clarity of the presentation.

This ability to convey fine detail, but on a grander scale, was apparent from Dire Straits’ ‘Telegraph Road’ [Love Over Gold, EMI; DSD64], where deep, well-rounded basslines were accompanied by the most minute of percussive ticks and Mark Knopfler’s careworn vocals. This is another song I’m very familiar with, but through the Constellation duo it was like hearing it anew, courtesy of the detail pulled from the mix, the subtle changes in timbre, and the confident handling of the dynamics.

Lovers of ‘Telegraph Road’ will know that its final five minutes are where the volume deserves to be pushed, although this is easier said than done with the Revelation 2 Preamplifier – its 100-step attenuator makes it easy to find the level you want, but makes it hard to go up or down quickly. Anyway, once set to a level that made full use of the listening room’s soundproof insulation, the power amp bounded along without belying any sense of strain, its dynamic flair and clean delivery intact. By the end of the song, my feet were tired from tapping while the amp seemed ready for more.

It’s a blast

Ease off the throttle for vocal-led performances, and the Revelation 2 system just continues to impress with the scale of its sound, and its blending of richness and detail. With Adele’s ‘Someone Like You’ [21; XL Recordings XLCD 520] it created a powerful vocal performance that was both big and intimate at the same time. The locked-in central image threw a spotlight on Adele’s bittersweet lyrics, given brilliant definition in front of piano chords that sounded thrillingly authentic.

The revealing and open sound of the Revelation 2 system (which I subjectively preferred using its ‘Balanced’ input, making use of its internal gain stage) means it easily turns its hand to other instrumental textures. John Barry’s ‘Bond Back In Action’, from Goldfinger: Original Motion Picture Soundtrack [Capitol/EMI; 96kHz/24-bit] came across in all its cinematic glory, with suspenseful strings contrasted with dramatic, throaty blasts of brass.

The same composer’s ‘Main Title’ for Kevin Costner’s Dances With Wolves [Epic ES 46982] is less idiosyncratic – more straight down the middle Oscar bait, really – but the Constellation system grabbed attention with the mass and weight given to the orchestra, and the sense of space around the players. The image depth was sublime too: military drums, followed by deep timpani beats, appeared far off in the distance.

The Gil Evans Orchestra’s cover of George Russell’s ‘Stratusphunk’ from Out Of The Cool [Analogue Productions; DSD64] is arguably a piece entirely about showing off the comically evocative tone of the trombone solo (played, I think, by Tony Studd). Again, this sounded vivid and real, a huge presence in the room precisely placed left of centre, before it faded away. As more instruments bubbled up in the stereo spread it was easy to visualise the band on the stage.

There’s no feeling that Constellation is softening the treble or managing the bass in pursuit of a more mass-market sound, which is as it should be given the likely partnering speakers. Playback of Prokofiev’s ‘No 2. In F Major Op 91: I. Allegro sostenuto’, by the Calidore String Quartet [Resilience; Signum Classics 96kHz/24-bit], was a masterclass in transient attack, decay, bite and texture. Even better was the spine-tingling sound of the Cappella Nova choir reciting James McMillan’s ‘Lux Aeterna’ [Super Audio Collection 6; Linn Records AKP 408], where the voices soared high into the church.

Grand funk

And, yes, the Revelation system appears effortlessly powerful, and grippy and tight with it. It let its hair down with ‘Good Times’ by Chic [The Best Funk Album In The World… Ever!; Virgin VTDCD44], delivering funky finger-plucked bass, fizzing hand claps and generally a happy, upbeat vibe. But even here, just as the Constellation amps had done with music as diverse as LTJ Bukem’s minimalist dance classic ‘Horizons’ [Looking Good Records; 44.1kHz/16-bit] or the croony blues of B.B King’s ‘Exactly Like You’ [Reflections; MCA 0602498010440], it brought out all the musical thrills on offer. So here comes the pun: these are a revelation.

Hi-Fi News Verdict

The minor cosmetic refresh to Constellation’s Revelation amplifiers does not reflect the transformation under the hood, where new, precision-engineered power supplies seemingly boost every facet of performance. Play any genre and this system excels, muscular and attacking one moment, insightful and fluid the next. It’s a premium sound worthy of the price, and a fine way to kick off the brand’s new era.

Sound Quality: 90%