Decware Zen Mystery Amp

July 16, 2015

Edgar Winter’s They Only Come Out at Night was the first record in my collection, so to say I’m intimately familiar with it would be an understatement. For old times’ sake, it’s the first album I place on the turntable when critical listening begins for the Zen Mystery Amp (ZMA). Wow! Just when you think you’ve heard it all and you know a piece of music inside and out, this amp whacks you upside the head—which is enlightening and it’s what keeps this reviewing game interesting. The first cymbal crash on Radiohead’s “High and Dry” further convinces me that I’m listening to something magical. There’s more air and delicacy everywhere. The ZMA is all about nuance and finding more information lurking in the details.

This is one of the most musical, most natural, most realistic amplifiers I’ve ever had the pleasure to live with—and it’s been with me for the better part of a year now. If you want to call BS, be my guest. (I’ve got my flame-retardant Kevlar suit on, so take your best shot.) After a crazed life of audiophilia and now 12 years of covering high-end audio as my day job, I still haven’t heard an amplifier that sounds more musical than the ZMA. My Pass Xs 300 monoblocks are on the short list, as are the Audio Research GS150 and Conrad-Johnson LP120SA+. Compared to the ZMA’s 40 watts per channel, all three of those amplifiers have more power on tap, making a wider range of speakers in larger rooms a possibility—but the sheer musical purity of the ZMA is tough to ignore, for a number of reasons.

Arf, Arf

Ever meet a small dog with a big soul? A 20-pound critter with more bark than a German Shepard or Saint Bernard? That’s the ZMA. I’ve always felt that you need a big amplifier to get big sound, but the ZMA not only plays damn loud for only having 40 wpc on tap, it has a ton of headroom. When it does clip, it does so in such a gentle manner that you’ll only notice a slight collapse of the soundstage, rather than sounding like you’ve just hit a sonic brick wall.

If you can live within the ZMA’s performance envelope, there is no reason to buy anything else, even for something two or even 10 times the price. The Holy Grail is right here, built proudly in Illinois. It only takes a brief listen to the ZMA to realize that the only mystery is how Steve Deckert can build an amplifier like this for $5,695 and still stay in business. If this piece of audio fine art had a Shindo or Wavac badge on the front, it would easily have another zero on the price tag. Take it from someone who’s owned both: Save the dough and buy American. The ZMA is a better amplifier than either—and it carries a lifetime warranty and tech support (for the original owner).

If the $12,000 Zen monoblocks are out of reach, or you just don’t have room for a pair of amps (albeit compact ones), the ZMA is essentially the same amplifier on one chassis, with a smaller power supply, delivering 40 wpc compared to the 60 wpc that the monos produce. I’ve been using the Decware Torii for the last few years and my only complaint is that I find myself wanting just a little more power. Even though the Torii is the little amp that can, there are times when 26 wpc just isn’t quite enough. In every way, the ZMA brings more to the table than the already excellent Torii, but above all things, it brings finesse.

Details, Details

It’s up to you whether or not God is in the details, but regardless of what you believe (or don’t) in the spiritual department, I submit that musical happiness does indeed lurk in the details. Happiness in the form of musical engagement is, for me, an experience that keeps you riveted to your listening chair, digging one record after the next, searching for those favorite tracks that, once you’ve heard them through the ZMA, have you searching for more. After several months, this still happens every time I fire up the ZMA.

Regardless of the tracks chosen, subtlety abounds with this amp, and it continually offers little surprises on so many records that I’ve been listening to for years. And listening to new music is equally dreamy. Trent Reznor’s soundtrack for the recent movie Gone Girl is so good it’s scary, constantly reminding me of the tension in the film. Reznor is known for his ability to build a dense and ethereal soundscape—and the ZMA, combined with the GamuT RS5 speakers, envelops me in so much more than what I might call a soundstage with another amplifier. The ZMA creates a hyper-real, three-dimensional sound sphere. While a record like this does not provide the picture of musical accuracy that your favorite Blue Note might, it does have many layers of minute detail—and through a less-capable amplifier, those details just don’t come through in the same dreamy sonic picture that the ZMA paints.

Tracking through well-known albums from Brian Eno and Jean-Michel Jarre prove equally ethereal. Jarre’s Zoolook features a track, “Diva,” with what sounds like water droplets behind layers of synthesizers, with Laurie Anderson saying something in reverse over the top. Trippy as this is, each layer breathes in its own space and, through the ZMA, Anderson’s voice sounds as if she’s just been let out of an asylum; it’s scary-movie good.

Sounding this good on surreal music, the ZMA excels when the fare turns to acoustic instruments. All of the texture, attack and decay associated with piano, guitar, drums and other acoustic instruments are revealed with shocking clarity. As a photographer, I can only describe this effect by saying its similar to going from a standard-definition picture to HD, and even to the latest 4K. The ZMA presents more and smoother steps of gradation, resulting in bongo drums sounding like actual bongos. There’s cheese and then there are cheese-like substances (i.e. Velveeta). Once you hear a piano or violin reproduced through the ZMA, it will be tough to go back to what you’d been using. As Bob Stuart at Meridian likes to say, “When you’ve heard it right, you can’t unhear it.”

The upper registers of the ZMA are as close to perfect as can be. Cymbals not only have the required meat, they have proper texture and decay. The same can be said for the lower register, which are even tougher for a tube amplifier to get right. Again, the ZMA succeeds brilliantly, producing low notes with tone and texture but also with the proper amount of speed and damping, without being overly damped. A picture may be worth a thousand words, but five minutes of actually experiencing the ZMA might well be one of the biggest “a-ha” moments I’ve had in high-end audio.

Setup and Further Listening

The ZMA arrives packed in a padded Pelican Case, with the tube complement in another box. Following the well-documented instruction manual will have you up and running in no time. Even after running the amp for a month, I didn’t have to rebias the tubes; and now after more than six months, they’ve required just a tiny adjustment to stay perfectly biased and matched to each other. Unlike with some tube amplifiers, the ZMA allows you to set each KT66 tube individually and does not require matched output tubes. It’s also worth mentioning that Decware encloses a power cord with the ZMA that a lot of other cable guys would nick you an extra thousand bucks for.

While the ZMA has two sets of binding posts, one for 4-ohm speakers and one for 8, Decware does offer an option that can power 8- or 16-ohm speakers—which leads to my only complaint with the ZMA: The high-quality binding posts are too damn close together. It’s tough to tighten them down onto fairly thick spade lugs like mine—but I will say that you can use banana plugs with ease.

Inputs are single-ended RCA jacks, with XLR inputs via Jensen 95khz transformers available as a $600 option. As Deckert points out, “while not a fully differential balanced circuit, it is still a tehnically balanced amplifier – and the transformer is your friend. It gives a beautiful shimmer to the top end and better dimensionality not unlike a great moving coil cartridge.” I must agree. Using equal lengths of Cardas clear via the XLR and RCA inputs, I do prefer the balanced inputs.

Those with only one source component who want to bypass the preamplifier can tick the stepped attenuator box for an additional $150. Should you fall in this category, this is the perfect shortcut to creating a highly resolving system on a tight budget (unless you have a world-class preamplifier—but then you’re probably not on a tight budget).

A bit of research on the Decware forum reveals that its claim of long tube life is no scam. Even after years, many Decware users are still running their original set of tubes! The 6N23P input tubes can be swapped for 6N1Ps or 6922s, but Deckert says the 6N23P is his favorite, and my experience is to follow his lead. While I leave the input and regulator tubes as installed from the factory, the tube swapping goblins do possess me to try a set of NOS Siemens EL34s in place of the KT66 tubes. The sound is just different, with the E34s being a little warmer and a little softer than the KT66s. Those liking a low-end that is a bit softer, flabbier and less controlled may prefer the EL34s, but I happily went back to the KT66s. Neurotic tube-swapping in my Torii led me back to what Deckert suggested in the first place, so from now I just listen to Obi-Wan.

However, I do believe the combination of 0A3 regulator tubes, fast recovery solid-state rectifiers and 4,500 uF of power supply capacitance is a big part of the ZMAs exquisite sound. This is way more power supply than any 40-wpc tube amplifier needs, or is supplied with any other similarly powered tube amplifier I’ve seen pass through our listening rooms. The ZMAs large, well-executed power supply translates into dynamic capability, a low noise floor and the ability to execute wide transient swings with ease.

Deckert has told me that his amplifiers just keep sounding better, as the wire in the output transformers becomes seasoned over the years. My experience with the Torii has been similar. After 100 or so hours of what audiophiles might consider “break-in,” this amplifier just keeps sounding more natural. The same is happening with the ZMA and I’m sure the person who ends up with our review sample will enjoy it even more in five years than I am today.

We mate the ZMA to some insanely expensive speakers: Focal Stella Utopias, Dynaudio Evidence Platinums, KEF Blades and now the GamuT RS5, as well as the Dali Epicon 8. All have a sensitivity rating between 87 and 89 dB and work well at modest to somewhat loud volumes. In my large listening room, I’m able to run the ZMA out of juice when going for fairly loud listening levels, but for most users in a more reasonably sized room, you will have to tax this one to get it to clip.

In my smaller room at more reasonable listening levels, the GamuTs, Egglestonworks Emmas (which were on our cover last issue) and a vintage pair of Acoustat 2+2s prove absolutely heavenly with the ZMA. We use Cardas Clear cable throughout and every speaker we test happens to work best on the output impedance setting that matches the factory rating.

The ZMA sounds great at turn-on, and while it takes longer to fully warm up than other tube amplifiers I’ve used, the transition from cold to warm is more gradual than any other tube amplifier I’ve used. Again, it’s that gradation thing.

This is the point where many reviewers make wry comments about how they will miss said review product dearly, and in regards to the ZMA, I must admit to having similar feelings. However, I’m looking at this more as an au revoir (since I’m saving for a pair of Zen Monos for my retirement.)

The ZMA is more than worthy of one of our Exceptional Value Awards. Considering the level of sound quality and build quality it offers, the ZMA is one of the most exceptional values I’ve ever encountered.

Decware Zen Mystery Amp

MSRP: $5,695

www.decware.com

PERIPHERALS

Analog Source AVID Acutus Reference turntable SP/SME V tonearm    Lyra Atlas cartridge
Phonostage ARC REF Phono 2
Amplification Robert Koda K10       Audio Research GSPre    Pass Labs Xs 300 monoblocks
Digital Source dCS Vivaldi four-box stack
Speakers Focal Stella Utopias    Dynaudio Evidence Platinums    KEF Blades    GamuT RS5    Dali Epicon 8    Egglestonworks Emma     Acoustat 2+2
Cable Cardas Clear
Power IsoTek Super Titan

Pass Labs XA160.8 Monoblocks

June 26, 2015

It’s no secret our publisher is incredibly enthusiastic about Pass amplifiers.  While the company’s flagship Xs300 monoblocks have been serving dual duty as his reference amplifiers and the furnace for the TONEAudio studio for some time now, his relationship with Nelson Pass is more than a mere bromance. It goes all the way back to the early 1980s, when we lived on Milwaukee’s East Side and he talked me into helping him carry his new Threshold 4000A power amplifier up a few flights of stairs.

I’m a tube guy; I’ve always been a tube guy – the tubey-er, the better. Back in 1980-something, that Threshold was a mind-bender because this massive solid-state amplifier made the room warmer than any tube amplifier I had ever experienced, sounded as musical as anything with glowing bottles, yet had killer bass output and control. It even sported an awesome set of red LED power output meters! The 4000A stayed in my system for a long time after our publisher’s terrier-like nose for all things audiophile led him sniffing down other paths and, as with one of my prized BMW 2002s, I still regret selling it.

It’s all about control

Don’t let Nelson Pass’s easy demeanor fool you; he wants control. At least control of your speakers’ cones. The major benefit to the massive power supplies and output stages in the two-chassis Xs amplifiers is the amount of control they enforce on your loudspeakers. Not letting the drivers act in a willy-nilly manner keeps distortion and non-linearity at bay, resulting in a cleaner, clearer, less fatiguing sound. Pass is fond of saying that he likes the sound of tubes without the hassle, and the Xs300s deliver this in abundance. But at almost $90K per pair they are not within the reach of every audio enthusiast.

Enter the XA160.8 monoblocks at $29,000/pair. Building on the success of the .5 series (you can read our review of the XA160.5 monoblocks here[1] and the XA200.5 monoblocks here[2] ) the .8 series of Pass amplifiers takes these designs a major step further. Larger power supplies and a more refined circuit allow these new amplifiers to be biased further into class-A territory. The changes draw more power from your wall, and generate more heat – something we put to good use here in the Pacific Northwest. The results put the 160.8 closer in sound to the massive, two-chassis Xs amplifiers than before. The price tag is still not pocket change, but a far cry from what the four-chassis, big boys will set you back.

Pass makes it a point to let you know that these are not cookie-cutter amplifiers, with each version sharing an input stage followed by progressively larger output stages. Every model in the .8 series is individually designed from the ground up with all nine amplifiers in the range using different input and driver circuitry optimized for progressively larger output stages. A peek inside the case reveals a prodigious bank of power supply capacitors flanked by equally huge heat sinks, each with “more output transistors than necessary.”

With balanced XLR inputs (the XA160.8 is a fully balanced design) and RCA inputs, this amplifier works well with any preamplifier. My ARC REF 5 proves a perfect match for the XA160.8, but after spending a bit of time with the top-of-the-line Xs Pre, I’m guessing it’s upgrade time again.  Even my standby CJ PV-12 turns in an amazing performance with these amplifiers and reminds me of when I used the Threshold 4000A with a CJ PV-2a preamplifier. Time does fly when you’re having fun. Watch for our review of that piece very soon. Suffice it to say that the XA160.8 will never be the weak link in your hifi system!

Taking care of business

Vicariously sampling the last four or five Pass amplifiers that have been in for review, it’s time to put the latest models front and center in my reference system and flog them. Rage Against the Machine’s “Take the Power Back” does the trick, as the intro kick drum beats and bass riffs occupy separate spots in the soundstage, neither losing their focus as I turn the volume up, up, up – pushing my head back against the couch. Yet near the end of the track as the pace settles to light cymbal work, the delicacy and texture rendered stops me dead. It’s so quiet and precise, everything appears to settle into nothing.

Sporting the big, blue circular meters that adorn the face of all the Pass power amplifiers, the 125 pound (each) XA160.8s are a breeze to move after the Xs300s. However, they’re probably a stretch for one person lifting, so you should consider getting some help to keep your back in order. For those not familiar with Pass amplifiers, the meter needle stays centered, indicating that the amplifier is operating fully in class-A mode, which for the 160.8, is 328 peak watts. So when that needle starts to bounce, these amplifiers are indeed producing major power.

Driving my Vandersteen 5As with the XA160.8s is absolutely peachy and the synergy with the Audio Research REF5SE is near perfection as well. I have spent some time with the Pass Xs Pre that is here for review, and that’s even more revealing. It goes without saying that you won’t go wrong with an all-Pass system, and as Mr. Pass says, you’ll never have to look for tubes again.

Break-in has been the same experience we’ve had with all other Pass amplifiers; they sound great straight out of the box and improve linearly over about 300 hours, with a minimal increase in clarity after that. Though solid state, they take as long as, if not longer than, a vacuum tube amplifier to fully “warm up.” Due to the power draw (550 watts per monoblock) and heat generated, most owners will not want to leave them on all the time. The XA160.8s take about 90 minutes to come out of the gentle mist exhibited at initial power up that dissipates after they reach full operating temperature. You’ll notice it in the smoothness of the upper register and the depth of the soundfield portrayed – getting deeper and deeper, drawing you further in to the presentation as they stabilize.

The 160.8s are consistent at low, medium and high volume. They never run out of steam when cranking AC/DC to near-concert levels, yet when listening to solo vocals or piano at levels barely above a whisper, maintain depth and a tonal richness that you’d expect from a flea watt SET amplifier. To say these amplifiers are incredibly linear and dynamic is an understatement.

In the end

We’re all worm food. But for now, if you find yourself asking the venerable question, “tubes or transistors,” this tube guy says buy the XA160.8 from Pass Labs. Unless you can afford the Xs monos, then of course you know what you must do.

Additional Listening: Jeff Dorgay

Selfishly, it’s always wonderful when someone else shares my enthusiasm for a piece of audio gear, and in this case, it’s been an ongoing argument between myself and Mr. O’Brien for a couple of decades now. While I agree with his analysis, because of the nature of the Vandersteen 5As only needing to be powered from about 80hz up, (because of their internally powered woofers) these speakers don’t give the full scale of the XA160.8s’ performance. And, of course, we like to perform amplifier reviews with as wide of a range of speaker systems as possible to see if there are any rocks in the road. I assure you there are none.

As with all the other Pass amplifiers we’ve auditioned, the XA160.8 continues the tradition of being able to drive any load effortlessly. I began my listening with the toughest speakers in my collection, the Magnepan 1.7s and the Acoustat 2+2s. Both passed with flying colors, and it was an interesting comparison to play the 2+2s with both the XA160.8s and a recently restored Threshold 400A that I used to use with my 2+2s in the ’80s. The more powerful, heavier, 4000A only stayed in my system briefly, but the 400A stayed for quite some time and was always a favorite.

Thanks to so much current on tap, the 2+2s now sound like there is a subwoofer in the room, but more importantly, these speakers, known for their somewhat loose and flabby lower registers are exhibiting taut, tuneful bass in a way they never have. Thomas Dolby’s “Pulp Culture” shakes the listening room with authority. An even tougher test is acoustic bass, and again the vintage ESL’s dance through all of my favorite Stanley Clarke tunes.

Moving through the gaggle of great speakers we currently have here from Dali, Dynaudio, GamuT, Eggleston and a few others, the XA160.8s have no limitations. To get them to (softly) clip requires ear shattering volume, or perhaps a pair of horribly inefficient speakers. In that case, there are always the XA200.8s and the Xs amplifiers.

No matter what music is served, the XA160.8s perform effortlessly and get out of the way for your enjoyment of it. The biggest delight, aside from knowing you’ll never have to hunt down matched quartets of power tubes again, is just how much of the flagship Xs300s capability is locked up inside these two boxes at one third of the price. Mind you in a “cost no object” system, the difference between the XS160.8 and the Xs300 will still be easily apparent, but it’s like the difference between an $85,000 Carrera and a $175,000 GT3RS – it’s easy to see, feel and hear the lineage,  and for those who don’t want to go all the way, will still find the lower-priced sibling still highly enjoyable.

I’ve hinted that the Pass XA160.8s have the slightest bit of warmth in their overall character, which they do. However, this additional richness and palpability is not at the expense of softness, or compromise in transient attack. If you want a strictly “nothing but the facts” the Pass sound may not be for you, but if you’ve always loved a touch of the glow that the world’s best vacuum tube amplifiers possess without having to chase the glass bottles, you must audition the XA160.8 I guarantee you will be highly impressed.

The Pass XA160.8

$29,000/pair

www.passlabs.com

PERIPHERALS

Analog Source SME 20/SME V arm     Koetsu Urushi Blue
Digital Source Simaudio MOON 650D    MacBook Pro
Amplification ARC REF 5     Pass Xs Pre
Speakers Vandersteen 5A
Cable Cardas Clear

Benchmark AHB2 Power Amplifier

January 27, 2015

The first thing you notice about the new Benchmark AHB2 is its diminutive size. Even with feet and binding posts, it’s only about 11 inches wide, 4 inches tall and 9 inches deep. And the heat-sink fins account for about a third of that width, making it even more incredible that Benchmark was able to jam so much oomph into such a small body. Regularly lifting amps that leave my back barking for Tylenol, I chuckle with relief when carrying the 12.5-pound AHB2 to my audio rack.

At about $3,000, the Benchmark AHB2 is a substantial investment, and it certainly demonstrates many musical characteristics one would expect at this price point. But the amp’s size makes it appealing when shelf space is limited or when you simply want to minimize your gear real estate. If more power is desired, you can buy a second AHB2 and configure them as monoblocks.

Benchmark offers the unit with a black or silver anodized faceplate and black heat-sink fins. A studio version is also available, with a wider front plate to fit equipment racks. Other than its tiny power button, the front of the amp has no other controls, just a few LEDs to indicate aspects of operation. Each channel has three LEDs to indicate clip, temperature and mute. In the event of an amp overload (which happened once during my testing), the amp shuts itself down and the LEDs indicate the nature of the problem. Powering the unit off, waiting a few seconds and pressing the power button puts the amp back into operational mode.

Setting the Benchmark

As Benchmark products are used regularly in recording studios, all of the AHB2’s connections are balanced. A couple audio designers have explained to me that balanced XLR connections usually prove superior to single-ended RCAs, since XLRs offer inherent noise canceling and they won’t come loose once clicked into place. If the rest of you’re system doesn’t offer XLR connections, Benchmark also makes cables and adapters.

Setup is fairly straightforward: Connect a preamp and speakers, ensure the stereo/mono toggle is set to the desired position, and then set the three-position sensitivity switch to match the signal levels from your preamplifier; the sensitivity switch also optimizes the amplifier’s gain for controlling volume from your preamplifier. Because of the amp’s size, its back panel can get crowed, making connections a little tricky—especially with my speaker cables, which have soldered spade connections that don’t bend. As such, I have to place the amp at the back edge of my audio shelf so the cables can hang below the amp (though I’ve had this same problem with other amps I’ve tested).
The AHB2 also offers twist-lock NL4 ports for speaker connection. Benchmark says NL4s provide lower resistance and higher current handling than connection via binding posts, as well as a more secure connection. As most speakers don’t have an NL4 connection option, Benchmark makes speaker cables with NL4 connectors for the amp side and standard connections for the speaker side.

Once everything is connected, simply push the power button on the front panel to activate the start-up sequence. When configured as a stereo amp, the AHB2 pushes out 100 watts into 8 ohms and double that into 4 ohms. For those wanting a 12-volt trigger for remote power-up, the AHB2 has you covered.

The AHB2 features a Class-AB/Class-H design (hence its name), which facilitates bridging a pair of the amps to use as monoblocks, pushing 380 watts into 8 ohms. This scenario is very useful if your speakers need some extra juice and you want to provide a dedicated amp for each, or if you want to drive a center-channel speaker in a home-theater setup. When using this setup method, consult the manual to ensure the proper connections and settings.

Meeting the Benchmark

Among Benchmark’s design goals for the amp were extremely low distortion and quiet operation. From the get-go, the amp lives up to its design specs by providing a very clean presentation. The Benchmark does a good job of layering vocals and instruments in all dimensions, with each element supported by a solid and convincing image. The amp’s designer, John Siau, is quick to mention that the third goal was to achieve a ruler-flat high-frequency response—and the AHB2 is completely flat all the way up to 200 kHz. Siau says these qualities are vitally important in delivering high-resolution performance.

As desired in a studio setting, the sonics from the AHB2 are neutral, and in my home setup, there is no observable emphasis in any particular frequency range. I would not characterize the AHB2 sound as warm or romantic, though it’s not stark or emotionless either. Between these two ends of the spectrum, the amp leans toward the latter but with a sweeter top end. Those seeking an amp that emphasizes fullness and richness that will augment slightly thin sound from your preamp or source might consider other amp options. But if accurate portrayal is a listener’s goal, this Benchmark does the trick.

When reproducing poor-quality recordings, the AHB2 does a nice job of limiting digital glare. Lucinda Williams’s album Car Wheels on a Gravel Road demonstrates the AHB2’s ability to offer edge-free portrayal of vocals with a very fluid midrange. Her voice resides upfront in the soundstage and it is well separated from the instruments accompanying her.

Regardless of music type, bass through the Benchmark offers a taught presentation with the snap and punch one expects from percussion. Depeche Mode’s “Personal Jesus” is engaging through the AHB2, with all the subtle synthesized sounds popping into position in the soundstage. This makes me curious about running a pair of the amps as monoblocks—which still wouldn’t take up the rack space of a single traditional amplifier.

The Benchmark brings to life the voice of the Martin Logan Motion XT35 bookshelf speakers. Considering its recording-studio applications, it makes a lot of sense that this amp pairs well with smaller stereo monitors. Combined with the speakers I have on hand for testing, the AHB2’s sound flavor profile remains consistent.

In the case of the AHB2, system synergy is an important factor to consider, since no amp is universally perfect for all speakers. For large and demanding speakers, a prospective AHB2 owner may need more power. In the case of the AHB2, you can add another unit and configure the two amps as monoblocks.

Additional Listening

By Jeff Dorgay

I was curious to hear how Benchmark’s design ethos of compact products would translate into designing a power amp. A couple years ago, the Devialet shattered my bias that amplifiers had to be massive to sound good, and so today I find myself much more open-minded to smaller amps like the Benchmark.

My initial exposure to the AHB2 was at this year’s Rocky Mountain Audio Fest, where Benchmark was playing the amp in an all-Benchmark system that included its new mini-monitor speakers. Back in my own listening rooms, the AHB2 did a fantastic job driving the KEF Blades, Dynaudio Evidence Platinums and even my Acoustat 2+2s, which are notoriously tough to drive, though a pair of AHB2s would have been even better for the 2+2s.

As both my reference systems are balanced, I actually prefer the XLR connections of the AHB2. If you’re working with single-ended RCAs connections, the Cardas adaptors are my favorite. I agree with Rob’s conclusions on tonality, etc., and will add that the AHB2 definitely has the bass drive necessary to achieve convincing full-range performance, even from big speakers.

In the end, the Benchmark AHB2 can become a great anchor to your system, offering high performance in a compact box. With an extremely neutral tonal balance, you can use it straight, or warm it up with a tube preamplifier, should that be your preference. Either way, the AHB2 is a stellar performer from a company known for excellence.

Benchmark AHB2 power amplifier

MSRP: $2,995

benchmarkmedia.com

PERIPHERALS

Digital Sources Mac mini, dCS Debussy DAC    JRiver Media Center 20    Tidal music service
Analog source SME 10 turntable with SME 10 tonearm and Dynavector 17D3 cartridge
Amplifier Burmester 911 MK3
Preamplifier Coffman Labs G1-A
Speakers Sonus faber Olympica III, Martin Logan Motion XT35
Cables Jena Labs
Power Running Springs Audio Haley power conditioner    RSA Mongoose power cords
Accessories ASC tube traps    Mapleshade Samson audio racks

Gato Audio DIA-250 Integrated Amp/DAC

January 3, 2014

Part of the mission here at TONEAudio has always been to remain on the lookout for magnificent hi-fi gear that not only performs well but is also a piece of visual art able to blend into any décor. Gato’s amplifiers caught my eye at this year’s Munich show, where I met importer Michael Kelly (of Aerial Acoustics), who was very proud of Gato’s latest creations. And lovely they are.

Hailing from Denmark, the DIA-250 features a small form that is remarkably able to contain a 250-watt-per-channel Class D amplifier and a 24-bit/192-kHz DAC, doing so at a very reasonable price of $4,500. Those requiring more power can step up to the DIA-400, which offers 400 wpc and has an MSRP of $6,000.

With ease and precision, the DIA-250 implements Class D amplification and upsampling signal conversion—two technologies that are big personal preferences of mine. It also provides major input and output flexibility to allow your system to grow, should the need arise. With a pair of balanced and XLR analog inputs to go along with USB, TOSLINK and S/PDIF digital inputs, the DIA-250 is a fantastic system hub. It also includes balanced and RCA variable outputs for those requiring an additional power amplifier or amplified subwoofer. HT bypass is also included for those needing to make the DIA-250 part of a multichannel setup, a feature sometimes overlooked.

Its gentle, curved shape—which combines brushed aluminum extrusions and a highly polished wooden top panel—is stunning, with one main control in the center to adjust volume level and two tastefully small buttons to select inputs and switch the amplifier into standby mode. The slightly blue-tinted display is easy to read from across the room, and it can be dimmed via an adjustment on the rear panel, or set to switch off completely after a few seconds. For those unhappy with the font choice, I submit (perhaps from a 50-something’s perspective, guilty as charged) that this feature is handy beyond belief, especially when living with a component for a long time. Those tiny readouts on other components might look a bit more stylish at first, but if you can’t read them, then what’s the point?

Setup, Sources, Speakers

I utilize a plethora of digital sources to evaluate the DIA-250, from a modest OPPO BDP-103, all the way up to the $36,000 dCS Vivaldi transport, with a few music servers and a MacBook Pro thrown in for good measure. All sources perform flawlessly, regardless of the chosen input.

With all of the digital sources being upsampled to 24/192 and then decoded by the DIA-250’s Burr-Brown PCM1794 converters, the sound is decidedly old school—and, for these ears, it is highly musical. My former digital reference, the Naim CD555, uses this setup brilliantly, proving that it’s all about implementation when it comes to the digital world.

Along with a variety of digital sources, the latest vacuum-tube phonostage from Van Alstine ($1,295), combined with a Rega RP3 turntable and Exact MM cartridge, proves an excellent match, giving analog and digital sources an equal voice during playback. The smooth character of the DIA-250 proves a perfect fit when spinning the latest releases from Music Matters Jazz, which I find enthralling. Lee Morgan’s trumpet on The Gigolo solidifies the fact that analog remains king, even on a journeyman rig like this. As much as I enjoy the digital section of the DIA-250 and its convenience, I would still highly suggest adding an analog front end to a system built around it.

The only area that the DIA-250 falls slightly short of its higher priced, Class-A or vacuum-tube competitors is in the area of image depth, but this is still endemic of the breed to some extent. And the DIA-250 is delivering music to the $85,000 Dynaudio Evidence Platinum speakers, which are not likely what this amp would be paired with—though you could with good result. For its $4,500 price tag, this is indeed a rocking little amplifier with integral DAC. Pair it up with your favorite speakers in the $3,000-to-$10,000 range and your music server of choice and you’ve got all the ingredients of an incredible system on a relatively reasonable budget.

Moving a bit downstream with the $8,500-per-pair Paradigm Signature S8 speakers also proves highly synergistic. The DIA-250 controls these tower speakers with aplomb, providing a rock-solid bass response and smooth highs. Combined with the S8s 92-dB sensitivity, the DIA-250 never feels the least bit strained, even at concert-hall levels.

Those using a sat/sub system will appreciate the additional flexibility of the variable outputs. The DIA-250 handles the JL Audio Fathom in-wall subwoofer mated to a pair of KEF LS50s with ease, so any powered subwoofer on your wish list should match equally well. And those of you using a REL subwoofer will have no problems connecting through the speaker outputs.

Getting Better All the Time

Class D continues to not only get more natural in its ability to reproduce sound but also in its ability to drive complex speaker loads. Just a few years ago, many Class D amplifiers were as finicky as any SET amp, but they have since come a long way. Full-range ESL and Magnepans are equally easy to drive with the DIA-250, though if you really like to push your Maggies, I suggest spending a few extra bucks and going for the DIA-400 to have the extra headroom at your disposal.

Regardless of which Gato amplifier you choose, Magnepan owners will be impressed at the amount of grip and drive these amplifiers provide. All too often the Class D/Magnepan combination comes across with a lack of timbral engagement, sounding somewhat flat—but that is not the case here.

Spinning the Volume Control

When I crank Metallica’s classic self-titled black album in a 24/96 format, it becomes instantly apparent that the Paradigm/Gato combination can satisfy those craving high sound-pressure levels. The first drum thwacks in “Wherever I May Roam” are highly convincing, pushing me back in my listening chair like the Maxell man. Bowie’s Scary Monsters keeps the classic-rock groove rolling and exposes yet another facet of the DIA-250: its ability to effortlessly uncloak inner detail. Robert Fripp’s guitar work on “Teenage Wildlife” is reproduced brilliantly, easily occupying its own space in the far left of the soundstage, while Bowie is anchored dead center in the mix.

Leaning heavily on an old audiophile classic, Dave Grusin’s “Sun Song,” from the recently remastered XRCD, reveals just how smooth this Class D amplifier and DAC combination can be. The opening triangle clangs float in the air, gently filling the room with sound. It’s amazing how far this amplifier technology has come in the last few years—saying Class D and DAC in the same sentence is no longer an audiophile faux pas. The delicate brushwork on Dave Holland’s “Overtime” is equally enthralling, and the extremely low noise floor of the DIA-250 enhances this effect.

The Bottom Line

The Gato Audio DIA-250 ticks all the boxes: It’s compact and gorgeous, and it sounds great—and, best of all, it’s priced right. With a comparison review in process between the DIA-250 and its companion, the higher-powered DIA-400, we look forward to hearing more of what Gato Audio has to offer. Whatever your power needs, both of these amps are highly recommended.

DIA-250 Integrated Amp/DAC

MSRP:  $4,500

www.gato-audio.com (factory)

www.aerialacoustics.com (US Importer)

Peripherals

Digital sources Meridian Control 15 server    Aurender S10 server    dCS Vivaldi transport    Oppo BDP-103    MacBook Pro
Analog source Rega RP3    Exact cartridge    AVA Phonostage
Speakers KEF LS-50    Magnepan 1.7    Paradigm S8 Signature    KEF Blade   Dynaudio Evidence Platinum
Cables Cardas Clear

Merrill Audio Veritas Power Amp Mono Blocks

September 4, 2013

Based in Bernardsville, NJ, Merrill Audio was formed in 2010 by Merrill Wettasinghe, a lifelong audiophile and former HP executive with a background in R&D.

The current product line consists of the Veritas line of amplifiers and the Lucia preamplifiers.  Merrill Audio has a clear vision for the products they offer, which are designed and built with an attention to detail rarely encountered. In for review are the Veritas Power Amp Mono Blocks, priced at $12,000 a pair.

The Veritas monoblock amplifier is a Class D design that uses the Hypex Ncore NC1200 power modules.  Each  chassis is machined from a solid block of aluminum with one-inch thick outer walls.  The internal electronic components are laid out in various chambers to maximize isolation.  Further examination leads one to conclude that very few, if any, compromises are apparent in the construction and layout.

According to Merrill, wiring is point to point, and Cardas ultra pure copper litz wire is used throughout the amps. Around back are Cardas speaker binding posts that utilize solid copper  and a rhodium plate; however, they will only accept spade terminated speaker cable.  The inputs are fully balanced and feature only top-shelf Cardas XLR connectors, so balanced cables are mandatory.  For an interesting touch, the units are supplied with power cords that Merrill has had custom-designed for them by Triode Wire Labs.  The IEC inlet is gold-plated Furutech. The monoblocks also ship stock with either synergistic or Stillpoints support feet.

The Veritas are not for those with weak backs, as they weigh in at 33 pounds each. According to Merrill Audio, their build process is as follows: “Start with a 66-pound solid aluminum block.  Delicately machine the chassis from this solid block with isolation chambers and frames to limit any sonic interference and minimize vibrations. Keep the walls one-inch thick, to limit and absorb vibration. The signal paths are designed to be the shortest possible, giving you the cleanest audio signal possible. Longer cables typically use shielding. Excessive shielding introduces capacitances that slow the dynamics of the system, especially power amps, bloating the bass and reducing the high frequencies. Keeping wires short removes the requirement for shielding…”

Setup is straightforward: a MyTek Stereo 192 DAC, Musical Fidelity M1 CDT transport, Bogdan Audio Creations Art Deco and Thiel CS2.4 loudspeakers, Audience power conditioning, along with Kimber cabling make up the review system. One interesting note is there is no power switch – the amps are turned on or off by detaching the Triode Wire Labs power cords, which results in a faint, harmless pop through the speakers. The Veritas monos also run warm to the touch, and have been left on continuously for optimum performance.

Listening:

The Veritas are given a few days of casual use to allow them to settle in, and then a steady diet of reference tracks for serious listening.  It is apparent from the very first listening session that the Veritas are very serious contenders for one of the biggest sounding amps to enter the listening room.  All the engineering, careful selection of parts, and attention to detail pay off.  The listener is rewarded with an enormous soundstage; feel-it-in-the-gut, super-controlled bass; and a wonderfully transparent midrange.

The topology of this amplifier never enters the mind during extended, fatigue-free, and highly engaging listening sessions. It is clear that many audiophiles have preconceived notions about certain amplifier types and, unfortunately, prejudge certain technologies without actually listening.  But with the Veritas, listening is believing.

The Veritas are nimble performers – aside from the excellent bass performance, the high frequencies are supple and delicate. Complex musical passages are rendered with a sense of effortless ease.  Listening with anything but full attention proves a difficult task.  All musical genres are rewarded equally with sublime transparency and appropriate scale.

The new album from Tom Jones, Spirit In The Room, is an amazing mélange of classic folk, blues, and rock. Jones and producer Ethan Johns call upon material from Richard Thompson, Leonard Cohen, Paul McCartney, and more. It is well recorded, and through the Veritas monos, the gravitas of Jones’s voice is remarkable.  Jones’s take on Leonard Cohen’s “Tower of Song” comes through with the necessary emotional impact.

Switching gears, the remastered  Collectors’ Edition of Joy Division’s seminal 1980 release Closer simply dazzles rhythmically and texturally. The Veritas shines a glorious light on the recording, which laid a foundation for the alternative movement of the 1980s, with stripped-down arrangements, melodic bass lines, and minimalist production.

The Veritas is also spot-on with acoustic music, especially classic jazz. Listening to various high resolution downloads of historic Blue Note recordings from John Coltrane, Joe Henderson, Wayne Shorter,  Herbie Hancock, and Freddie Hubbard is a gas. Drums, horns, piano, and bass all sound natural in timbre and free from grain. Wayne Shorter’s Speak No Evil is a particular favorite with the drive and soul that the Veritas provided this classic recording.

The Veritas are so resolving, it is easy to hear the changes in upstream components, cables, and tweaks. The amps are remarkable in this regard, making it easy to detect something as simple as switching a power cord or two in the system. As revealing as the Veritas are, they never seem analytical or soulless. Quite the opposite, actually. They paint a holographic picture of the performers when the recording allows, without being the least bit mechanical.

On an ergonomic note, the Veritas runs slightly warm to the touch and responds positively to quality amplifier bases and speaker cables. It is utterly noiseless and offers some of the quietest operation experienced in this reviewer’s system. This manifests itself in a pristine soundstage and the ability of the listener to distinguish even the most subtle aspects of a recording.

Conclusion:

At $12,000 per pair, the Merrill Audio Veritas Mono Block amps are certainly not entry level components; they provide a sonic picture virtually without flaw across the musical spectrum. Mind you, the Veritas for this review are installed in a system normally built around tube amplification.  The fact that tubes have not been missed in the least during the review period speaks volumes about the vision of Merrill Audio.

The Merrill Audio Veritas Mono Block amplifiers may very well be a breakthrough in Class D amplifier design.  The fact that the amplifiers are equipped with such performance enhancers such as high-end vibration control, top-shelf wiring, and connectors that many far more expensive amps cannot claim is impressive and makes these amps plug ‘n’ play.  The build quality of the Veritas is beyond reproach, and the footprint of each amp is relatively small, which means easy installation.

The time spent with the Merrill Audio Veritas Power Amp Mono Blocks was nothing less than enjoyable with long, satisfying listening sessions. They have the ability to drive virtually any pair of speakers without a hint of strain, and with a clarity and precision most often seen at the very upper echelon – highly recommended for those seeking a transparent amplifier with power to spare.

The Merrill Audio Veritas Mono Blocks

MSRP:  $12,000/pair

http://www.merrillaudio.net

Associated Equipment:

Transport: Musical Fidelity M1 CDT, Squeezebox Touch w/CIA power supply

DAC: MyTek Stereo 192 DSD DAC

Speakers: Bogdan Audio Creations Art Deco, Thiel CS2.4

Cables: Kimber, Stager, DH Labs, Transparent

Accessories: Audience aDeptResponse

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