China’s AURALiC, a relative newcomer to the hi-fi industry, has stepped into this crowded scene with some quality products, and the company sets a high bar for itself with each new release. Seeing AURALiC’s new MERAK monoblocks (priced at $5,000 per pair) freshly out of their packaging is a bit like seeing a great tuxedo-wearing magician backstage before a much-anticipated performance. It’s easy to admire the polished outward appearance, but as anticipation begin to grow, it becomes clear that something interesting will happen when the curtain rises, leaving one to wonder if the performance will live up to expectations.

Smoke and Mirrors?

In every way, these amps offer substantial build quality and beautiful fit and finish. The sleek, brushed metal exteriors of my test pair sport a matte-silver finish—but the modest exterior does not reveal what’s hidden beneath the handkerchief. These mono monsters offer 400 watts of juice into 4 ohms and half of that into 8 ohms. According to AURALiC, the MERAKS’ capacitors hold enough energy to deliver 16 amps of peak current and 900 watts of power. By comparison, my reference amp—a Mark Levinson 335 stereo amp—pushes 500 watts into 4 ohms. From a power perspective, I never feel that my power-hungry Piega P10 speakers are limited with the Meraks in the chain.

Not a full Class D design, AURALiC refers to the MERAK as a hybrid design using Class-A signal amplification, switching output stage and linear power supply, sounding surprisingly like another very exciting amplifier that graced our cover a couple of years ago. In daily use, these monos never get hot, even when they are powered up for a couple weeks continuously. In addition to the stellar energy efficiency of the MERAKs, their design allows the user to stack them in an audio shelf without worry of overheating. Each amp measures 11 inches wide, 11 inches deep, and 2.75 inches high, so even in a two-tier configuration the amps’ physical footprint remains modest.

By sharp contrast, moving my Mark Levinson 335 stereo amp (which should have come with a coupon for a hernia operation) requires a friend, or a couple post-move aspirin. The MERAKs, which weigh 18.7 pound apiece, are extremely easy to carry by comparison. In fact, I’m able to carry one amp under each arm and still have a spring in my step.

Sleight of Hand

Connecting the amps is as simple as expected. I must give AURALiC kudos for including Cardas CE binding posts with the amps. Clamping a single knob down onto a tough plastic bracket holds my speaker cable’s spade terminations against the posts. And it’s so easy to get a good finger hold on the knob that I don’t need a post wrench (or a kung-fu grip) to get a tight cable connection. I should note that this knob-bracket combo does not accommodate banana cable terminations.

The MERAK s offer only balanced XLR inputs, and so given my single-ended preamp, I choose to enlist the help of some adapters. After contacting AURALiC to see if they have any specific recommendations for or against that approach, I get the thumbs-up for adapters, which do the trick. After testing them with my Levinson to ensue they don’t color or cloud the sound to any significant degree, the adaptors are easy enough to drop in place. Once flicking the rear switch to activate the amp, pressing a small button on the front puts them in and out of standby mode, which a small LED indicates.

Firing up the MERAKs without source material playing, I’m amazed by their silence. If it weren’t for the LED indicator, I’d wonder if they were powered up at all. With the rest of my audio chain shut down, only the ribbon tweeter of my Piegas can reveal any audible hiss—and only when I put my ear against it. I leave the amps on for two weeks straight for both burn-in and stress testing and I never experience anything from my listening position except great music. That’s a disappearing act indeed!

Rabbit from a Hat

Switching designs inherently bring a lot of positive merits. First, their power-to-weight ratio offers very good value for the dollar. They also sip energy (rather than gulping it), which makes them the more environmentally friendly option. These amplifiers have come a long way in the last few years, but I generally find them lacking some of the subtle detail, frequency extension, and sonic emotion I’m accustomed to with class-A or AB designs. But contrary to my assumed impressions, the MERAKs provide some very welcome surprises that challenge my past views in meaningful ways.

During my first listening session, covering about 20 tracks of various music types, several characteristics stand out immediately. The MERAKs do not romanticize the sound, nor do they leave it overly stark and cold. They strike the right balance. They also do a very nice job of creating the ambience and reverberation around the musicians.

Also impressive is the soundstage they throw, which is both wide and tall. There are no perceived boundaries and the sound extends well beyond the speakers. Additionally, they do a very good job of layering instruments in depth. Music reveals itself both in front of and behind the plane of the speakers. Vocals stand out front and the other instruments fall into their proper alignment behind the vocalist. This characteristic is one of the MERAKs strengths and it’s very engaging with all types of music. Few tracks illustrate this better than Portishead’s Roseland NYC Live on vinyl. When delivering the track “Roads,” the MERAKs pull Beth Gibbons’ voice out front such that the illusion of the singer extends into the room and creates an appropriately upfront but unaggressive presentation. There’s no stridency, and vocals retain the engagement they should command. The MERAKs also place the sound of the crowd clapping along well into the background.

Enya’s album Watermark does present two noticeable downsides that my Levinson does not. First, with all the juice that the MERAKs bring, they most definitely take control of the speakers and maintain a tight command, which results in the bass losing a bit of low-frequency punch and definition and the highs losing a bit of sparkle. Secondly (and more subjectively), there’s a reduction in the underlying emotion of the song.

It’s hard to put a finger on this at first, but after listening to several tracks on various albums—both digital and vinyl—I notice a consistent signature to the MERAKs. There’s a slight veil, which results in the reduction of the nuanced detail and delicacy that gives increased realism to good recordings. Of course, this quibble is in comparison to an amplifier priced around $8,000, yet the Meraks run for only $5,000 a pair. At that price difference, I’d expect the Levinson’s performance to exceed the MERAKs’ by a significant margin.

Abracadabra!

Delivering the disco-y tunes Daft Punk’s Random Access Memories, proves to be a joy, with a very nice integration of instrumentation, and the perceived pacing of the music brings a captivating energy to the recording. A remastered Royal Edition recording of Mozart’s symphony No. 36 performed by Leonard Bernstein and the New York Philharmonic also illustrates the MERAKs’ prowess with wide dynamic swings.

Pink Martini’s “Omide Zendegani,” and other tracks from Get Happy, similarly reveals an ability to pristinely render more intimate songs with a small combination of vocals and instruments. But, where necessary, the amps are also able to decipher a complex array of instruments across the soundstage.

Take a Bow

As with a great magician, it’s hard not to be impressed with MERAKs’ capabilities and finesse. Of the class-D designs I have experienced so far, these top my list sonically – I’m sure the hybrid design contributes to this sense of ease in a big way. Compared to my favorite class-A and class-AB amps, the MERAKs have only a few tradeoffs, as noted above. At the same time, there is a lot to love—and kudos again to AURALiC for taking switching amplifier design further toward an elusive sonic pinnacle than my past experiences. Even when mated with very revealing and power-hungry speakers, the MERAKs never take the sound into the realm of stridency, and considering their other merits, it’s easy to settle in for a long listening session of great music.

While $5,000 is a significant financial commitment for most people, what you get with these amps represents great value in terms of watt-per-dollar ratio. There are many good amps in this price range, so the MERAKs face some stiff competition—but with oodles of power and very good sonics, these amps are certainly worth your consideration.

Additional Listening

The folks at AURALiC are on a roll.  We’ve had the pleasure of listening to almost their full line now, and they all share an equal level of sonic excellence, build quality and elegant visual understatement.  Best of all, the gear is reasonably priced, over delivering for the prices asked.  This just might be the next big brand in world of hifi, no small achievement.

I concur with Rob on all of his observations, and feel that the MERAKs strike a fantastic balance of timbral and tonal accuracy, major dynamic slam and a complete lack of fatigue.  Putting them through their paces with the KEF Blades, the Focal Maestro Utopias and the Dynaudio Evidence Platinum speakers proved the $5,000 pair of AURALiC amplifiers were not out of place in a six figure system.

However, like every other switching amplifier I’ve had in the listening room, the MERAKs benefit from careful attention to what’s coming from the AC line.  While they offer great sonics just plugged into the wall, a top notch power line conditioner will take them to an even further level of clarity.  And, should you need a bit of warmth in the mix, you can always pair these amplifiers with your favorite vacuum tube preamplifier.

In short, the AURALiC MERAK amplifiers offer tremendous sound for a very reasonable price.  We look forward to see what they will come up with next.  Maybe a 250 watt per channel stereo amplifier in one box?  Hmmm.

MERAK monoblock amplifiers

MSRP: $5,000 per pair

www.auralic.com

PERIPHERALS

Speakers	Piega P10
Amplifier	Mark Levinson No. 335
Preamplifier	Coffman Labs G1-A
Digital Sources	Audio Research CD3 MKII    Light Harmonic DaVinci DAC    HP 2.5 GHz Quad Core running Windows 7 and JRiver Media Center 19.0.32
Analog Source	Marantz TT-15 turntable with Clearaudio Virtuoso cartridge
Cables	Jena Labs Valkyrie and Symphony interconnects    Jena Labs Twin 15 speaker cables
Power	Running Springs Audio Haley power conditioner    Cardas Golden and Golden Reference/Mongoose power cords
Accessories	Mapleshade SAMSON racks and shelves    ASC TubeTraps    Cathedral Sound room-dampening panels    Coffman Labs equipment footers

What do you get for a whopping $205,000 dollars?  You get real music, provided you have speakers and ancillaries up to the task.  Each of Boulder’s massive 3050 monoblocks weigh 450 pounds and supply 1500 watts of Class-A power per channel, delivering an experience beyond anything I’ve ever heard.  The price tag of awesome is rarely a small one.

You also need a dedicated 220/240-volt line for each monoblock amplifier.  My wimpy 20-amp dedicated lines are not enough for me to commandeer a pair of these for review, so I go to the mountains of Boulder, Colorado, home of Boulder Amplifiers.  Forget the usual audiophile excuses about how a review can’t be written without the product being in your own system, because in this case the Boulder listening room features a pair of Focal Grande Utopia EM speakers, a model I am very familiar with.

“We haven’t sent these out for review because no one has enough AC power in their listening room to accommodate these,” laughs Boulder’s Rich Maez as we tour the factory.  And I’m guessing that only a privileged few also have floors stout enough. For those with enough power on tap and hefty floors (and the wherewithal to afford a pair), the 3050s arrive with Colorado-mined black granite bases that perfectly match the asymmetrical shape of the amplifiers.

The Epitome of Craftsmanship

The visit begins in the machine shop, where the exquisitely machined parts that make up a Boulder amplifier come to life.  Each 3050 heat sink is machined from a 115-pound solid billet of 6061-T1 aluminum alloy.  Once through Boulder’s various CNC machining centers, the amps undergo a series of final finishing operations, ending with bead-blasting and clear-anodizing processes.  As impressive as the chassis and heat sinks are, perhaps the coolest part of each Boulder 3050 is the massive power switch, which features a highly polished paddle machined from stainless steel.  It’s actuation feels like the clunk of a Bentley door.  (Click HERE to visit our website for more pictures of the Boulder factory.)

Shop foreman Ian Balmforth has been with Boulder for over 15 years, having inherited the job from his father, and he takes a tremendous level of pride in his work.  The rest of the employees in the Boulder factory share the same level of enthusiasm for their work, often putting their efforts and expertise into different phases of component production and for different models.  When orders are ready for a batch of 3000-series components, they work on nothing else until the run is complete.  Whereas so many products are built in hours, the Boulder 3050 monoblocks take approximately four weeks each to complete, from the time the raw metal enters the dock until the finished, tested and safely crated amplifiers leave.

Fully balanced, differential power amplifiers from start to finish, the 3050s offer only balanced inputs, and the driver stage consists of Boulder’s latest discrete 99H modules.  A giant metal tunnel runs through the center of the amplifier chassis, with four separate, potted transformers inside, which helps drop all mechanical and electrical noise to the theoretical minimum.

Power and Control

The Boulder 3050s have more power than anything else you can buy, but sheer watts are not the whole story.  Boulder’s president Jeff Nelson explains it as a “factor of control,” telling me that the more power available and the more devices to distribute the load—there are 120 output transistors in each 3050—the easier and more precisely the amplifier can control the movement of the speakers’ drivers and the EMF that the woofer cones generate.

Rich Maez begins my listening session of the 3050s with an introduction to the range.  Everything is driven by Boulder’s 2010 preamplifier and 1021 network disc player.  The 1008 phonostage we reviewed back in issue 27 sits on another rack with a SOTA turntable.  AC/DC’s “Rock and Roll Ain’t Noise Pollution” plays through the 800-series monoblocks (also reviewed in issue 20) with good results.  Everything Boulder is famous for is here in spades with this $12,000 pair of amplifiers:  Bass weight and control, lightning-fast dynamics and a big soundstage—impressive and duly noted.

Switching the cables to the 1050 monos and then to the 2050 monos clearly illustrates the progression.  Tonality remains the same, but each pair of amplifiers reveals more music than the models before.  Going up the range brings a lower noise floor, more weight and more dynamic jump.  And the 2050, which has been Boulder’s flagship for years, is indeed impressive, with the Grande Utopias turning in a truly grand performance.

For those not familiar with the Focal Grande Utopia EMs, they are one of the world’s finest loudspeaker systems, but their stunning level of resolution can disappoint if the rest of the system doesn’t deliver the goods, and I have heard this speaker turn in more than one lackluster performance over the years with mediocre systems.  (That’s my polite way of telling those of you who don’t like the Grande Utopias to shut your pie holes…insert smiley face.) They excel here.

Music’s New Definition

Wonderful as the 2050s are, the 3050s are a quantum leap in every aspect of performance.  Revisiting the AC/DC track is a stunning experience.  The Grande Utopias simply liquefy in the room now that the 3050s are powering them; there seem to be no speakers whatsoever, just music.  Tonality remains the same, but soundstage width and depth jumps to another level with the 3050s.  The Grandes become even more coherent, fading further into nothingness.  I’ve been listening to Back in Black since the day it was released in 1980, and I’ve never heard it like this.  The drums now have the force to convince you that you’re listening to the real thing, along with the right texture and tonality of the various drumheads.

Miles Davis’ “Freddie Freeloader” stretches out between the speakers, with natural-sounding cymbals and endless texture present in the recording; it feels as if you can hear all the way inside his horn.  This speaker-amp combo delivers a similar effect with the piano, which just floats directly out in front of the left speaker and is rendered to perfect scale, as a drumstick cracks down on the rim of the snare and Miles’ trumpet glides in so gently you don’t even notice it until the sound is there in full force.

These amplifiers deliver unbelievably tight pace and texture in the low-frequency register, regardless of volume level, again giving a feeling of being in the performance instead of just listening to it.  Acoustic bass is fleshed out perfectly, with just the right amount of resonance and texture, while electric bass growls as it should.

Unlimited Dynamics

Revving up the tempo with a dose of hard bop, Rich goes for some Freddie Hubbard, whose horn on “Philly Mignon” blows me back in the listening chair—Maxell-man style.  The complete lack of clipping or compression continues to amaze me as the hours roll by.  The opening bit to Pink Floyd’s “Welcome to the Machine” feels as if you are in an elevator 6 feet under the floor, moving up through solid matter to listening level and then up another three stories.

The bongos in Bob Dylan’s “Everything is Broken” take on a life of their own, sounding much larger than life.  While I’ve often dismissed Dylan’s Oh Mercy album as flat and uninvolving at the standard 16-bit/44-kHz resolution, it comes alive in all three dimensions in this system.  I don’t even want to listen to vinyl!

More time goes by as I investigate countless tracks that I’ve heard time and time again on many systems.  I’m continually amazed by the new experiences these amps deliver—from the Beatles to Metallica.  As Ella Fitzgerald and Louis Armstrong run through “Isn’t this a Lovely Day,” I feel as if the room’s walls are missing and the performers are walking around me as they sing.

Playing music through the Boulder 3050 monoblocks is hallucinogenic.  Continually stunned by everything I choose, I don’t want to leave the listening chair, but by now it has become dark and everyone but Maez and Nelson have long gone home for the day, so it’s time to call it a night.

Boulder achieves the ultimate with the 3050s:  They resolve more detail than anything I’ve ever experienced, yet they are never harsh or off-putting in any dimension.  As I listen to quite a few albums I am infinitely familiar with (some of which are not known for their sound quality) the music comes alive through the Boulder/Grande Utopia combination in a spectacular manner.  I’ll go on record to say that this is the most musically lifelike system, coming the closest to the real thing I’ve ever had the pleasure of listening to.

Meeting the Goal

Boulder president Jeff Nelson claims his company’s ultimate goal is to produce an amplifier devoid of sonic signature, one that lets the music come through as it may.  For this reviewer, Boulder has succeeded fantastically.  In the early 1990s, in his review of Boulder’s original 500AE power amplifiers, Stereophile editor at the time, J. Gordon Holt, said that the amplifiers “are just not there.”  Though incredible progress has been made in 22 years, this still remains the essence of the 3050s.  They truly disappear, becoming a conduit of music unlike anything I have experienced.

The paradox of the Boulder 3050s is twofold:  Hearing them will reset your bar in terms of what is possible in the world of reproduced sound, even if you only listen to average recordings.  They will also spoil you for anything else.  You don’t really need that 401k, do you?  You’ll be too old to enjoy it anyway, right?  For our readers fortunate enough to afford a pair of 3050s, I guarantee you will not be disappointed.

In addition to otherworldly sonic performance, Boulder amps come with a level of craftsmanship that is also beyond anything else I’ve experienced.  Most Boulder amplifiers produced over the company’s history are still in use, and most are still owned by the original owners.  Boulder doesn’t do “mid-model updates,” and a quick glimpse at eBay shows only a couple pieces for sale on the secondary market, and they command high prices.  (Three of the six sellers say their reason for selling is that they bought the next piece up in the Boulder line.)  I can’t imagine where you would go after owning a pair of the 3050s.

Those a little less well heeled might consider the 900-watt-per-channel 3060 stereo amplifier, which sells for $115,000.  It will still require a single 30A 240-volt outlet, but Rich Maez assures me that it offers up a very enticing experience.

Having spent plenty of time with some of the world’s top amplifiers, I can tell you that the Boulder 3050s deliver the goods.  This is not a case of paying three times as much for a miniscule increase in performance; this is a mind bender.  You’ll never be the same.

Boulder 3050 Monoblock Amplifiers

MSRP:  $205,000 per pair (including granite bases)

Boulder Amplifiers

www.boulderamp.com

Even with a track that is not bass heavy, the Pass Xs 300 amplifiers immediately show their superiority.  Sinéad O’Connor’s luscious voice on “Bewitched, Bothered and Bewildered,” from her album Am I Not Your Girl? lingers in the air between the KEF Blades in a way that it never has before—her voice is bigger and airier, with a higher degree of “reach out and touch it” than I’m used to.  And when Michael Jackson takes us through a time warp with minimal accompaniment, courtesy of The Stripped Mixes, he truly feels right in the listening room about five feet in front of the couch.  The realism is staggering.

In the world of high-end audio, where Internet-forum pundits loudly proclaim that expensive gear is not worth the money and that its curve of performance versus diminishing returns is incredibly steep, I must strongly disagree in favor of the Xs 300s.  Having lived with Pass Labs’ $22,000-per-pair XA160.5s monoblocks for over a year, and then having stepped up to the $34,100-per-pair XA200.5s (a huge jump in performance) and now taking the leap to the $85,000-per-pair Xs 300 two-chassis monoblocks, I’m still staggered at how much more of everything is available with Pass’ flagship amplifiers.

Here in Portland, Oregon, one of America’s greenest cities, my aging hipster friends would mess themselves if they knew I had a pair of amplifiers that draw 1,000 watts each, all the time.  Okay, so I’ve thrown concerns about my carbon footprint out the window with these amps, but I do walk to work and I’ve replaced all 22 of the 50-watt halogen bulbs in my studio ceiling (along with the 15 in the house) with LEDs that only draw 7 watts each.  That just about makes up for the power that these massive monos consume.  I’d light the place with candles and eat dirt before I’d give up these amplifiers!

As TONE staff member Jerold O’Brien helps me unpack these super-sized beasts, which weigh in at 168 pounds for the power supply and 130 pounds for the output stage, we become awestruck:  The Xs 300s have six banks of output devices per channel and Pass has increased the bias current by a factor of 10 compared to the XA amplifiers.  And as Pass Labs’ Desmond Harrington is fond of saying, “This means more control.”  Interestingly enough, Jeff Nelson of Boulder Amplifiers says the same thing, and both the Boulder 3050 monoblocks and the Xs 300s are definitely the two most incredible amplifiers I’ve ever heard (for those of us who are not worried about the price tag).

Where the mighty Boulders take more of a “just the facts, ma’am” approach, the Xs 300s sound more like a gigantic tube power amplifier with tighter grip and more bass grunt, while retaining the airy character and ravishing tonality that you would normally associate with vacuum tubes.  I’d happily put the Xs 300s up against any vacuum-tube power amplifier on the market, regardless of price, and I’d still prefer them to tube power.  The Xs 300s are equally yummy, and knowing you’ll never have to forage for power tubes again is a major bonus.

Love at First Listen

O’Brien and I are both equally stunned when we begin to hook up the Xs 300s.  Way too anxious to just let one stack sit there while taking the photos for this review, we connect one of them to the GamuT S9s.  We look at each other and O’Brien exclaims, “Dude, your system sounds better in mono with one of these than it does with the pair of XA200.5s.”

Strong words indeed; this is the level of performance increase that comes with spending twice as much money with a reputable company.  If you’ve ever fallen deeply in love at first sight then you know how this is.  The Xs 300s are love at first listen.  (After months of using them with an incredibly wide range of speakers, from the $1,500-per-pair KEF LS50s to the $150,000-per-pair GamuT S9s, I’m even more smitten with them now than the day I unpacked them.)

By the time we have the photos done and the second channel connected, it’s time for some shut-eye, so the Xs300s are left to play all night, and we’ll reinvestigate them in the morning.  As is the standard procedure with massive class-A power amplifiers if they are going to be on all night, no heat is needed in the studio.

The next day’s listening session begins with a comfortably toasty listening room, but more importantly, the amplifiers are now thoroughly warmed up.  Normally, we always leave solid-state power amplifiers on 24/7, but this is just not practical with the Xs 300s, because they produce such a prodigious amount of heat.

Boxes Ticked

The amount of sheer control the Xs300s provide is unbelievable—there is truly nothing they won’t do.  When we swap out a few of the other amplifiers we have on hand for the Xs300s (even the awesome XA200.5s), it feels as if a subwoofer has been added to the system, even with the tiny KEF LS50s—which, incidentally, sound amazing through these four-box wonders.

It isn’t just all power and punch, though:  These amplifiers offer the magic of incredibly high resolution, without throwing delicate tonality out the window.  You’ll notice tasty little nuances in your favorite well-worn recordings, prompting the desire to revisit as many of them as possible.  I predict many late-evening listening sessions once you get these fully broken in.

A perfect example is Ornette Coleman’s Ornette on Tenor. This straightforward bop record features great interplay between Coleman on sax and Don Cherry on trumpet, backed up with bass and drums—a sparse mix to be sure.  The sax and trumpet tear it up across the wide stereo mix, with the drums and bass exploding from the left and right channels, respectively.  The scale at which all of this takes place, especially in the way the Xs 300s render height, makes it all sound so convincing.

The Hammond organ sounds fabulous as it creeps into the mix at the beginning of War’s “The World is a Ghetto.”  The Hammond is barely there, just skating in and out of your consciousness, but it adds an unmistakable texture to the track—all the better in 24-bit/192-kHz resolution courtesy of HDtracks.  All the while, the funky, wah-pedal-laden guitars segue in over layer upon layer of horns.  Backing up to “The Cisco Kid” proves equally enlightening.  When a piece of gear can render a track that you’ve heard way too many times and still keep you riveted, you know you’re onto something special.  This is what the top of the mountain looks like, or rather sounds like—and it’s good.  No, it’s wonderful.

Those who live and die by the sword of pace and timing will be equally enthralled with the Xs300s.  The needle in the gigantic round meter on the front panel of the amplifier chassis stays firmly planted in the center, indicating that the amp is staying in single-ended class-A operation.  Until pushed well past reasonable and prudent levels, the needle barely ever budges, as is the case when powering the 90-dB-per-watt KEF Blade speakers.

Jazzman Marc Ribot’s Silent Movies is a collection of atonal tracks that exhibit laser-sharp focus through the Xs 300s.  The decay of Ribot’s heavily processed guitar on “Natalia in Eb Major” is so realistic that I’m magically transported back to the 10th row at the Montreal Jazz Festival as I soak it all in.  As Ribot switches from distorted electric guitar to clean acoustic, the Xs 300s allow the notes to just linger in the air so that you can feel the strings resonate.

Comfortable at All Levels

Even at practically intolerable volume levels, the Xs 300s hold their poise completely, with no soundstage collapse whatsoever.  Audioslave’s “Gasoline” is by no means an audiophile darling, and it’s actually somewhat compressed; yet, on a great system this track can be unraveled.  With the meters just beginning to budge from their stops, I can feel my brain rattling around inside my head from the sheer sound-pressure level, but the pounding drums and lead guitars stay in place and Chris Cornell’s high-octane scream stays anchored, drilling itself into my being.  These amplifiers remain composed, even at these elevated levels.

Yes, this kind of listening is bad for your eardrums, but being able to pressurize your listening room at near concert levels (no matter what kind of music you enjoy) is enthralling to say the least, so use the Xs 300s with care.  A sound-level meter would be an apt accessory for these amps.

In the end, every aspect of music reproduction sounds more convincing with these amplifiers.  Pass Labs founder Nelson Pass has always been a proponent of the “first watt” methodology (i.e. if the first watt doesn’t sound great, why bother with the rest?), and he went so far as to built a pair of small power amplifiers bearing that name.  We’ve reviewed most of the First Watt amplifiers and they are superb; the massive Xs 300s manage to retain that same level of delicacy while still providing major power.  There are just some speakers with which 15 watts per channel simply won’t cut it.

Setup and Stuff

If you think you really don’t need 300 watts per channel of class-A power, think again.  The combination of speed, control and bone-crushing dynamics offers an experience you just don’t get with less power, even at low listening levels—it’s more about the control these big amplifiers provide than just power.  Incredible acceleration is an added benefit of all this power, along with the ability to stop instantly.  The Xs 300s are lightning fast with no hangover or fatigue.  They’ve been playing nearly nonstop since they arrived, and at the end of a 16-hour day I can still keep going back to the record rack for just one more.

Like the other Pass amplifiers we’ve used, the Xs300s require about 100 hours of play to be all they can be, but they are damn good straight out of the box.  Once you become intimately familiar with them, you will notice that they sound slightly hazy at first turn on, and gently yet linearly they come out of the fog over the course of about 90 minutes.  Everything just gets easier as they reach operating temperature.

Because of the heat they generate, these amplifiers need ventilation, and Pass confirms that you can stack the chassis one on top of the other, but be sure to give them plenty of room.  And if you are in tight quarters, make sure you have decent HVAC.

The Xs 300s can be used with balanced or RCA inputs, though they are fully balanced amplifiers.  The ARC REF 5 SE and Robert Koda K-10 preamplifiers work fantastic, as do the Simaudio MOON Evolution 850P and Burmester 011.  Even my vintage ARC SP-11 Mk. 2 works well, but the high resolution of the Xs 300s does reveal the limitations of this great vintage piece.  The only real downside to the Xs 300s is that you’re likely to find yourself wanting linestage and source upgrades.

A pair of enormous cables connects the chassis with the biggest Neutrik connectors I’ve ever seen.  I plug each monoblock set into a dedicated 20-amp line, even though the power cords are of the 15-amp variety—there’s no point in putting regular gas in your Aston Martin, right?  The four speaker binding posts are the super-coolio Furutech carbon-fiber jobs that ratchet tight and click when you’ve reached the proper torque, which is a nice touch.

The $85,000 Question

Though saying so may result in some hate mail, the Pass Xs 300s are worth every penny of their $85,000 price tag.  Considering a few other amps on the market that I’ve sampled, Pass could probably charge an even 100 grand for them and easily get away with it.

But you have to ask yourself a couple of questions before making this kind of a purchase decision:  Do these amplifiers take you somewhere you’ve never been before, giving you an experience that you just can’t get with a lesser product?  Are they built with a level of precision, care and attention to detail commensurate with other products at a similar price?

Yes and yes—and then some.  Fortunately, I’ve had the privilege of listening to a lot of fantastic amplifiers in the $20k-to-$40k range over the last few years, and the Xs 300s are considerably better.  They reveal more music and are more transparent, with bottomless dynamic power and they present no problem driving any of the speakers I have at my disposal.

So if you’ve got the system, the software and the scratch, buy these babies—you won’t regret it one bit.  And the couple of readers I’ve talked to who have jumped off the cliff agree with me.  These are indeed very special amplifiers.

Pass Labs Xs 300 monoblocks

MSRP: $85,000 per pair

Pass Laboratories

www.passlabs.com

Peripherals

Analog Source	AVID Acutus Reference SP turntable    TriPlanar and SME V tonearms    Lyra Atlas and Clearaudio Goldfinger SP cartridges
Phono Preamplifier	ARC REF Phono 2 SE    Indigo Qualia    Pass Labs XP-25    Simaudio MOON 810LP
Digital Source	dCS Vivaldi    Sooloos Control 15    Aurender S10
Speakers	GamuT S9    KEF Blade    Sonus faber Aida    Sonus faber Guarneri Evolution
Cable	Cardas Clear
Power	IsoTek Super Titan

No matter your drug of choice—chemical, horsepower, audio—with prolonged use, you always reach a plateau at which you believe you just can’t get any higher. But sooner or later, something else enters your reality that restarts the cycle, and you’re off and running again. Such is my experience with the Pass Labs XA160.5 monoblocks.

If you are new to the world of high-end audio, you can get the condensed history of Pass Labs here: http://www.passlabs.com/about.htm. The shorter version is simple: Nelson Pass is a genius. He’s probably got more patents for amplifier design than almost everyone else combined. And he’s got a great sense of humor, too. The owner’s manual describes the new amplifier as “tending to run heavy and hot, but elicit high performance and reliability from simple circuits.”

Weighing in at about 130 pounds each and $24,000 per pair, the XA160.5s are not for the light of wallet—or bicep. Or, for that matter, air-conditioning capacity. The power draw isn’t huge, but each unit sucks 600 watts from the power line, whether idling or at full power. Because they only produce 160 watts per channel into 8 ohms, doubling into a 4-ohm load, they get very warm to the touch. Yes, this behavior is normal for a class A design. The extra heat was welcome in March when the amplifiers arrived, as it kept our studio toasty. Yet, as days got longer, the amps forced us to run the A/C well before we normally would.

Super Yet Simple

Pass has always advocated keeping things as simple as possible. While squarely looking at the enormous monoblocks might cause you to question whether he still believes in this basics-minded philosophy, thanks to Pass’ patented SuperSymmetry design, the amplifier has only two gain stages. At the risk of oversimplifying, the SuperSymmetry approach achieves low distortion (and tonal purity) by making each half of the balanced amplifier as close to identical as possible so that the resulting distortion from each half of the amplifier circuit cancels out in balanced mode.

To achieve maximum performance, the amplifier must be run in balanced operation. Fortunately, the ARC REF 5 offers balanced and single-ended outputs, which makes comparisons a snap. And Pass is right again: Utilizing the XA160.5 in single-ended mode proved very good, but it featured a layer of grain not present in balanced mode. Whether you use a Pass Labs preamplifier or a model from another manufacturer, make sure to take the balanced route.

Coming Full Circle

My first experience with Pass’ class A amplifiers came in 1979. I combined a Threshold 400A with a Conrad Johnson PV-2 preamplifier driving a pair of Acoustats, making both an incredibly natural combination and excellent case for pairing a solid-state power amplifier with a tube preamplifier. While many combinations have since passed through my room, the tube pre/solid-state power amplifier is always the one to which I’m drawn, especially when it involves a class A amplifier.

The XA160.5s symbiotically works with all of the preamplifiers at my disposal, but the match with the Audio Research REF 5 linestage and REF Phono 2 preamplifier is heaven-sent. Pass Labs president Desmond Harrington tells me that many customers use the company’s amplifiers with tube preamplifiers. “It’s a popular combination, but when it comes to power, we like to see our amplifiers offering the tube sound without the tears.” Truer words haven’t been spoken.

As someone who’s purchased more than a fair share of power tubes, I am relieved to know that the sound of the XA160.5’s will never change. And, you won’t have to buy new power tubes every year. Continuous operation cuts down on tube life. If only Costco sold tubes by the palette.

Like Luke, I Ignored Yoda Just Once

Pass’ instruction manual cautions against using the XA160.5s with a power conditioner. Nonetheless, I plugged them directly into the wall and then into my Running Springs Maxim power conditioner, with the latter providing an even cleaner presentation. The soundstage opened up significantly, and I didn’t experience any loss of dynamics. Yes, the stock power cords that come with the XA160.5s are very good, but aftermarket power cords (Shunyata and Running Springs models yielded excellent results) offered up a slightly clearer window to the music.

In all fairness, think of superior power cords as being able to take an amplifier that goes to 11 up to 11.2. Besides, you wouldn’t put regular gas in your Porsche, would you?

Super and Scrumptious

Unlike a non-class A solid-state amplifier, the XA160.5s shouldn’t be powered on for 24 hours a day. They generate too much heat. Still, just like a tube amplifier, the XA160.5s need an hour to warm up and stabilize. At first turn on, they still sound great, but once you get used to them, you’ll notice a slight haziness that softly dissipates as the clock ticks. Coincidentally, the ARC REF 5 and REF Phono 2 need an hour to sound their best, too, so if you are using a tube front end, everything will warm up at the same pace.

I initially listened to familiar digital tracks from the Sooloos music server/dCS Paganini combination. I was immediately taken aback by the additional weight and depth, even more so with high-resolution digital files. All of the class A amplifiers with which I’ve lived share a tonal richness that other solid-state amplifiers do not possess. Some might refer to this quality as warmth, but I prefer to call it tonal richness. I associate warmth with slowness, lack of pace, and rounded-off treble; the XA160.5s exhibited none of these characteristics. The Pass monoblocks sport the equivalent of a great guitar’s ability to sustain a note. On a choice Gibson Les Paul, for example, music just seems to hang in the air a little longer.

Switching back and forth between amplifiers at my disposal revealed that the XA160.5s are indeed very special. It was as if the particular characteristics from my favorite amplifiers have somehow taken up residency in one model. Thanks to their monoblock design and huge power supplies (the 160.5 is claimed to have a significantly larger power supply than the 160 it replaces), these amplifiers throw a soundstage that is prodigious in all three dimensions. Image width really stands out.

I noticed such traits on all program material, but they became more obvious when listening to classical. Conveying the size of a symphony orchestra—much wider than most listening rooms—is one of the toughest feats to ask a system to accomplish. When listening to Sir Arnold Bax’s sixth symphony, it felt as if the sidewalls in my listening room had been each moved out about six feet. Not realistic, of course, but much more convincing than without the XA160.5s.

Recorded live and flush with ambience, Hugh Masekela’s “Stimela (The Coal Train)” from Analogue Productions’ 45RPM 2LP version of Hope provides an excellent test. Having just heard Masekela perform the song at the Montreal International Jazz Festival in June, the recorded version via the Pass amps colored me impressed. While the live version claimed a slightly different arrangement, the XA160.5s pushed my GamuT S9s to a realistic sound level and conveyed such nuance and tonal contrast, I felt like I was back in Montreal’s Club Soda venue. Even at the high volume level, the front panel’s deep-blue backlit oval meter barely flinched from its center position, indicating that the amplifier never left class A mode.

Of course, man cannot live on jazz alone. At prime operating temperature, the XA160.5s did not miss a beat on a Japanese vinyl pressing of Michael Schenker’s Built to Destroy. No matter how hard I pushed, I could not destroy the amps or my speakers. And yes, that’s a very good thing. Staying in Japanese LP mode, Bruce Springsteen’s The Wild, The Innocent, and the E-Street Shuffle proved tough to resist, as did David Bowie’s Aladdin Sane. These old favorites never sounded better, and when I quickly switched back to the gear I’ve lived with for some time, across-the-range performance boosts became manifest.

Staggering Pace and Tonality

While classical music plays to one group of the XA160.5s strengths, revisiting the recently remastered Beatles catalog plays to another: These amplifiers offer rock-solid pace. Violins in the mono version of “Eleanor Rigby” (from Revolver) were strongly anchored, and Lennon and McCartney’s voices unwavering. There was so much depth, it almost sounded like a stereo recording! Speaking of the latter, the stereo version of “Penny Lane” from Magical Mystery Tour turned out to be just as exciting. Ringo Starr’s drumming and McCartney’s bass held true throughout the psychedelic soundscape.

I am easily swayed by the big sound of these amplifiers, yet that characteristic only scratches the surface of their capabilities. Concerning tonal accuracy and texture? Spot on. Acoustic instruments sound correct, whether listening to wind, string, or percussion instruments. Dynamic contrasts equate to the best I’ve experienced. A few TONE writers whose tastes skew towards classical remain astonished at the lifelike piano reproduction.

Music fans that crave vocal performances will benefit from the XA160.5’s picture-perfect tonality and resolution. Again, the extra tonal body almost feels as if one is listening to an SET—albeit an SET with nearly unlimited power that you can use with real-world speakers. The extra low-level resolution goes a long way, especially when spinning marginal discs. An ideal example comes courtesy of Keith Richards’ Talk is Cheap. Richards is not known for possessing a terribly strong lead vocal. Yet, when put through the XA160.5s, it actually has some depth. Such is the XA160.5s’ allure. They hover at the optimum point of boasting maximum resolution without being harsh, sounding full bodied and musically natural without introducing tonal distortion— a difficult balancing act.

Bass response keeps in line with the exceptional performance found elsewhere in the frequency range. While the XA160.5s have more than ample weight and slam, the bass reveals a level of texture and detail that I’ve only experienced with a small handful of amplifiers. Remember: It’s easy to confuse “audiophile bass” (usually over-damped and distinguishable from the real thing that has life, texture, and resonance); the XA160.5’s are the genuine article. A cursory listen to your favorite acoustic bassist reveals the way these amplifiers allow the instrument to breath, and brings you that much closer to the actual performance.

Top Contenders

Two years ago, I proclaimed the Burmester 911 Mk.3’s the best amplifiers I’ve heard. And over the course of hundreds of product reviews, I’ve used that dreaded “B” word just once in the absolute sense. After conveying my enthusiasm for these amplifiers to Harrington, he responded, “The 160’s are amazing, but you need to hear the 200s.” So just when I thought I couldn’t get any higher, the quest begins again.

It’s always tough to make comparisons, yet the XA160.5 combines the virtues of my three favorite amplifiers into one (actually two) boxes:  the delicacy of the Wavac EC300B, the texture and dimensionality of the ARC REF 150, and the power, control, and composure of the Burmester 911s.

Independent of the “B” word, the Pass Labs XA160.5 monoblocks orbit the top stratosphere of amplifier design at any price. If you would like that je ne sais quoi that you thought required a vacuum-tube amplifier, these are a consummate alternative. There is nothing that the XA160.5s do not do.

The Pass Labs XA160.5 monoblocks

MSRP:  $24,000/pr.

www.passlabs.com

Peripherals

Analog Source	Audio Research REF Phono 2     AVID Acutus Reference SP w/SME V tonearm and Koetsu Urushi Blue cartridge    AVID Volvere SP w/SME 309 tonearm and Grado Statement1 cartridge
Digital Source	dCS Paganini stack    Sooloos Control 15
Preamplifier	Burmester 011    Burmester 088    ARC REF 5    McIntosh C500   Conrad Johnson ET5
Speakers	GamuT S9
Power	Running Springs Dmitri    Running Springs Maxim
Accessories	Furutech DeMag    Loricraft RCM