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Audio Research Corporation Reference 160S Stereo Power Amplifier

The Audio Research Corporation needs no introduction. Its foundational contribution to the audio world is well established. I have lusted after various ARC products over the last 35 years. Pretty much all ARC’s tube gear—from the 1987 SP9 preamp a neighbor owned when I was starting out to the more recent REF250 power amps, and many products in between—has fostered a kind of “inner life” within recorded music. The even more recent Reference 160M monoblocks vaulted my interest yet higher. When I heard them at industry shows and in audio shops, they sang with a clarity, finesse, and dynamic command that struck me as a new frontier for ARC. Now, we have the stereo version of the 160M—the $22k Reference 160S.

I didn’t have a pair of Ref160M ($34k) monos on hand for direct comparison, but with the stereo Ref160S in my system I did hear qualities very similar to those of the monos in other systems. This is no surprise, since the Ref160S has the same circuitry, tube complement (four KT150, two 6H30 per channel), and power rating (140Wpc) as the monos. The feature set is also the same—output-tube auto-bias, front-panel output-tube monitoring, ultralinear/triode-mode buttons, and “floating” power meters on a see-through faceplate. On the rear panel we have 4-, 8-, and 16-ohm taps, an output-tube hour-counter, a cooling fan control, an auto shut-off, and RCA/XLR input switches. The Ref160S is a bit larger in all dimensions (mostly depth) and weighs a lot more than a single Ref160M (100 pounds vs. 56 pounds), no doubt to accommodate two channels’ worth of stuff in a single chassis. (The only circuitry difference—as far as I can tell—is that the Ref160S shares one power transformer for both channels, whereas the 160M has, of course, one transformer per amplifier.) The stereo amp actually has a slight edge over the mono in aesthetics in my opinion: The 160S’s transformers are covered in their own nice-looking vented cage with the Audio Research logo on top, whereas the 160M has exposed transformers—if one removes its larger, “whole amp” cage cover to expose the tubes. The Ref160S also has two rear handles, which the Ref160M lacks, that make moving its 100-pound chassis easier. (For a more detailed explanation of the Ref160M/160S circuit and tube complement in the context of ARC’s development as a company, please see Executive Editor Jonathan Valin’s excellent Ref160M review in Issue 294. For more information about Audio Research Corporation as a company and its contribution to the audio arts, please refer to the ARC section in The Absolute Sound’s Illustrated History of High-End Audio, Volume Two: Electronics.)


Right from the start, the Ref160S had a wonderful, fluid, agile quality. Music skipped along with engaging litheness that did not immediately scream “classic tube amp,” in the sense of imparting a slight sluggishness on transients and some looseness in the bass. Actually, the Ref160S is the most powerful, nimble, and neutral-sounding tube amp I have had in my system. (For twenty years, until 2009, I used to run mostly new [not vintage] tube preamps and power amps exclusively.) The Ref160S combines just a touch of warm-side-of-neutral tonal balance with remarkably low—for a powerful tube amp—underlying noise, so it joins a group of tube gear from brands such as VTL, VAC, Lamm, Ypsilon, and Atma-Sphere that bucks classic tube amp sound in this regard.

Ref160S rear cover

In keeping with tubes’ typical strengths, the Ref160S had both midrange resolution and 3-D depth—both of the larger soundscape and of individual images—in spades. Though not quite as extended at the extremes as some good solid-state amps, it also expanded midrange resolution to the immediately adjacent parts of the frequency spectrum—to a degree that helped everything sound more realistic and less obviously “tube-processed.” Mind you, the Ref160S’s top end was a little softer than I am used to from the solid-state amps (Gamut, Constellation, Hegel) I have been recently using, but I did not get the sense that I was missing much sonic information when I considered the whole picture. In fact, the Ref160S reproduced the gestalt (as TAS founder Harry Pearson liked to say) of a full orchestra in a way that made me think, “Wow, that gets a lot of it right!”

It may seem like a conundrum, but the Ref160S had such a low noise floor and its image boundaries were so free of “electronic etch” or “fizz” that its upper frequencies might strike some listeners as missing the last bit of extension and information, compared to certain other amplifiers. But the Ref160S actually made music sound more lifelike, to my ear, than most other amplifiers in terms of its refined image outlines and lack of electronic grain. Maybe it was the sense of continuousness that tubes bring to bear, or the midrange lucidity, or the sense of physical presence, or the wonderful musicians-in-a-hall effect with their trailing tails of notes lingering in space a bit longer (all of which the Ref160S does so well) that contributed to an overall “reminiscent-of-live” impression. Because of this truly fine realistic quality, I was motivated to revisit some of my classical LP collection: the Poulenc Concerto for Strings, Tympani, and Organ [Erato], Canteloube’s Songs of the Auvergne [EMI], and Mozart’s Concerto No. 21 in C Major [Phillips] were reproduced with remarkably natural-sounding details and immediacy. I found new aspects of the performances’ phrasing and developmental arc—new “musical meaning,” if you will—with the Ref160 in play. (Choreographers Glen Tetley [Voluntaries], Leslie Jane Pessimier, [Les Chansons] and Jiří Kylián [Petite Mort] used the music listed above, respectively, to create wonderful neo-classical dance works, by the way.)

Pop and rock had forward momentum in a parallel to the lucid gestalt in classical music. There was plenty of transient snap and power to give well-recorded drum kit, for example, the sense of acceleration that well-recorded drums contribute to the mix. I didn’t hear the Ref160S’s musical appeal across different genres as overtly euphonic as such; rather, the Ref160S simply brought out elements in recordings that illuminated the artistic expression inherent in music more readily—provided the recordings had decent performances and were well recorded in the first place, of course. It was as if the musicians had a particularly good night at the concert hall, club, or recording studio. We have probably all attended a live performance on one evening and then heard the same group or orchestral program again on another night and regarded one evening’s performance as better than the other. The players were clicking more with each other or the singer was in particularly good voice or the sound engineer got the levels and microphones’ phase-matching right. The Ref160S seemed to have the effect of making home listening sessions come closer to a superior evening’s performance. When one of my long-time audiophile friends said upon hearing a few cuts through the Ref160S, “Wow, the music sounds really alive—I could easily live with that amp,” I got it.

The Ref160S had a very deep soundstage, the deepest I have heard in my system. Front-to-back layering was continuous and closer to real life than many amps can muster, especially amps of the solid-state variety. Images within the soundscape were fleshed out as more completely formed sound sources created by real people and instruments in space, rather than as flat cutouts or bas-relief tableaux. The front of the soundscape was moved more forward than I am used to, so this—combined with slightly narrower soundstage width—created an overall stage that was sometimes closer to a cube in shape than to a rectangle whose width is greater than its depth. I suspect some of the amp’s slightly narrower soundstaging could be the result of the Ref160S being a stereo amp rather than a monoblock. (All things being equal, a pair of monoblocks tend to cast a wider soundstage than the equivalent stereo version.) Also, I believe the Ref160S is meant to be paired with an ARC preamp, like a Ref10 or Ref6SE, which themselves recreate very wide, expansive soundscapes. (Unfortunately, an ARC preamp was not available during the review period to test this hypothesis.)

Bass was deep reaching and powerful. The Ref160S’ plumbed the depths with ease, not exactly a typical tube amp’s forte, especially when one considers the speaker I used was the YG Sonja 2.2, which generally fares better with a high-current solid-state amp. While not quite matching the speed and definition of some solid-state amps, the Ref160S had the best bass pitch definition and stability of any tube amp in my system. Dynamics were also very good, both macro and micro. The big, meaty sound the Ref160S produced stemmed, in large part, from its ability to track bass-laden dynamic peaks with sustained control. The Ref160S never clipped or showed signs of strain while in ultralinear mode. It did lose control and clip, however, on the big orchestral stuff while in triode mode (70Wpc).  I think most folks who listen in triode mode would presume it is better suited to smaller, less demanding music (or to an easy-load speaker). Speaking of triode and ultralinear modes, I did nearly all of my listening in ultralinear. While the triode mode did offer some additional warmth and intimacy on smaller-scale music, I didn’t find the difference compelling enough to be worth switching back and forth between the two modes on appropriate music selections. On the whole, I found ultralinear to sound tonally closer to neutral and more dynamically responsive.

The Ref160 gives off a lot of heat, but that comes with powerful tube-amp territory. ARC uses cooling fans to keep operating temperatures within optimal range and extend tube life. Since I placed the Ref160S in front of my equipment rack to make connecting it to and from my system easier, I did hear the fan during very quiet music passages, even with the fan speed set to low. I believe most users would place the amp in a more room-friendly position, and that would, no doubt, be farther away from the listening position. Let me add, the Ref160M/S aesthetics are a welcome change for ARC whose typical look has tended to be more industrial and functional. I liked the see-through faceplate, but I turned off the lighted VU meters, as I found them to be a little distracting. A friend thought they looked really cool and wanted to see them with their light level all the way up. (There are three levels plus off.)


The winning combination of a low noise floor, which allows details to emerge in an unforced way, and very high levels of image solidity, which produces a closer-to-live listening experience, is central to the Ref160S’s appeal. Add in uncommonly good bass presence and dynamic control, and you have a tube amp that goes a long way to furthering the strengths of valves while mitigating their typical weaknesses.

To my mind, the Ref160S doesn’t try to sound like a solid-state amp as such; it is, rather, a high-quality amp in its own right, and can outperform most solid-state designs in depth layering and musical fluidity. If you feel like venturing into the glories of tubes or continuing your tube amp adventures on a different plane, consider the Ref160S. It is highly recommended.

Specs & Pricing

Tube complement: Two matched pairs KT150; two 6H30 per channel
Power output: 140Wpc (20Hz–20kHz)
THD: Typically 1% at 140 watts, below 0.04% at 1 watt, 1kHz
Power bandwidth: 5Hz to 70kHz (–3dB points)
Frequency response: (-3dB points at 1 watt) 0.5Hz to 110kHz
Input sensitivity: 2.4V RMS balanced for rated output
Gain: 25.5dB into 8 ohms
Input impedance: 300k ohms, balanced; 100k ohms, single-ended
Output taps: 16 ohms, 8 ohms, 4 ohms
Damping factor: Approximately 14
Overall negative feedback: 14dB
Slew rate: 13 volts/microsecond
Rise time: 2.0 microseconds
Dimensions: 19.0″ x 10.25″ x 21.5″ (with handles and connectors: 24″)
Weight: 100 lbs. (net)
Price: $22,000

6655 Wedgwood Road North, Suite 115
Maple Grove, MN 55311
(763) 577-9700

Associated Equipment
Analog source: Basis Debut V turntable & Vector 4 tonearm, Benz-Micro LP-S MR cartridge
Phonostage: Simaudio Moon 610LP
Digital sources: Hegel Mohican CDP, HP Envy 15t running JRiver MC-20, Hegel HD30 DAC
Linestages: Ayre K-1xe, Hegel P30, Constellation Audio Virgo III
Integrated amplifier: Hegel H390
Power amplifiers: Gamut M250i, Hegel H30
Speakers: YG Acoustics Sonja 2.2, Raidho TD1.2, Dynaudio Confidence C1 Signature
Cables: Shunyata Sigma signal cables, Nordost Heimdall 2 USB, Shunyata Alpha S/PDIF and AES/EBU, Shunyata Sigma NR and Omega XC power cords
A/C power: Two 20-amp dedicated lines, Shunyata SR-Z1 receptacles, Shunyata Everest 8000 and Typhon power conditioners
Accessories: PrimeAcoustic Z-foam panels and DIY panels, Stillpoints Ultra SS

KEF Creates Maximum Bass in Minimum Space with NEW Uni-Core Technology

The following is a press release issued by KEF.

Marlboro NJ, 14th January 2021 – Audio Manufacturer KEF is releasing a brand new groundbreaking technology called Uni-Core, which delivers a completely new take on speaker and subwoofer design. This latest innovative technology developed by KEF redefines size versus performance by enabling high-level performance while reducing the subwoofer or speaker cabinet volume significantly.

With the ambition to create an aesthetically pleasing piece of audio equipment to complement your living room, it was also imperative that KEF not only maintain but excel in their delivery of accurate and deep bass. Between desirable aesthetics and uncompromising performance the first challenge was fitting two drivers into a compact cube enclosure.

“To deliver deep and loud bass from a compact product is a big engineering challenge,” says Dr. Jack Oclee-Brown, Head of Research & Development at KEF. “The Uni-core is a breakthrough technology for KEF because it allows us to pack two drivers into a tighter space without compromising their performance.”

Uni-Core uses two dual force-cancelling drivers with concentrically arranged, overlapping voice coils, that are driven by a single motor to provide stunning bass performance from a small enclosure. The voice-coils are different sizes and occupy the same physical space within the Uni-Core driver assembly. This allows for an extremely compact physical cabinet with significantly reduced volume when compared to subwoofers that rely on conventional driver technology.

The saved space provides the drivers far more excursion than an equivalent-sized, force-cancelling design, unlocking more output and depth from much less space. This patent-pending technology smoothly delivers powerful and deep bass response while removing the space concerns that are often obstacles to premium subwoofer performance.

The new Uni-Core technology will be applied in an upcoming KEF product that will be announced this month. To discover more on KEF, please visit: https://us.kef.com/.

Secret Machines: Awake in the Brain Chamber

After a decade in limbo, Dallas-bred alt-rock cult favorites Secret Machines return with an emotionally charged and sonically forceful fourth album. Building on the kinetic flavor of their haunting 2004 debut Now Here Is Nowhere, Awake in the Brain Chamber is a volume-challenging mesh of fiery guitar, evocative keyboards, and propulsive drumming. It’s a fitting homage to their onetime bandmate guitarist Benjamin Curtis, who left the fold in 2007 and sadly passed away from lymphoma in 2013. Working on and off for 10 years, surviving bassist/keyboardist/vocalist Brandon Curtis (Benjamin’s older brother) and drummer Josh Garza honed eight songs that blend unavoidable melancholy with a fierce drive to plow forward. Aptly named opener “Let’s Stay Alive” crackles with the full force of Garza’s muscular drumming, while Curtis’ dreamy vocals serve as a 21st-century bridge between the Machines’ inherent shoegazing tendencies and unabashed space-rock heroics. “Everything Starts” sews in sinewy guitar accents from the late Benjamin Curtis, and the guttural “Talos’ Corpse” teems with defiant resolve. Brain Chamber is a welcome reawakening from a long-lost band not yet ready to sign off on their final chapter.

The Cat’s Grin

Jonathan Valin wrote the following essay in response to the Point/Counterpoint in the last issue, in which Robert Greene and I presented diametrically opposed views of the roles of listening and measurement in evaluating audio equipment. —Robert Harley

To start, let me just say that I am very very glad that Dr. Robert E. Greene has recovered from his illness. If you’re comparing big differences to littler ones, what could be bigger than surviving a near-death experience, where being here and not being here are the stakes? I am extremely happy that Dr. Greene is still with us. The petty disagreements about hi-fi that he and I have had over the years matter not—hi-fi itself matters not—in this biggest of all pictures.

Having said that (and said it from my heart), I have to add that denying the existence of sonic differences because they are “too small” to verify by measurement is the exact opposite of Harry Pearson’s “observational” approach to hi-fi. This is not to say that questioning or expanding upon Harry’s ideas (which is what Dr. Greene is doing and what I myself have done and am about to do) is verboten; it’s just that quoting Harry incredibly selectively to support your position on, oh, wide-dispersion loudspeakers and soundstaging, while simultaneously going squarely against his core idea (which is that listening trumps measurement, always and invariably) is more than a bit misleading.

But rather than chastising Dr. Greene for heresy, let me confess one (very big) heresy of my own: I don’t believe in the absolute sound—at least, I don’t believe in it exclusively. Instead, I see three closely related but nonetheless distinctive and equally valid ways of listening to stereo systems and judging their excellence.

My first group of listeners, staked out by Harry and this magazine, is what I call the “absolute sound” bunch. For them, the thing that matters most is how closely and convincingly reproduced sound approaches the sound of the real thing. It doesn’t really matter how a speaker or amplifier or turntable or server manages to create the illusion of actual acoustic instruments in a real space; all that matters is that it does—whether that be by design, accident, coincidence, or adherence to or deliberate departure from the measurable (or un-) “truth.”

While profoundly important and influential, the idea of the absolute sound is not unproblematic. The trouble is that the absolute sound, as I often said to HP, isn’t absolute. What you hear in a concert hall is fundamentally dependent on all kinds of variables (e.g., the hall’s acoustics, where you’re seated in the hall, how the players themselves are spaced on the stage floor, what kind of instruments they are playing, how “warmed up” or not those instruments are, etc.). The result of all this relativity is that what sounds “absolute” to you in your orchestra section seat close by the double basses (which is where Harry customarily sat in Carnegie Hall) may be—in fact, will be, in ways large and small—different than what sounds “absolute” to another listener who sits in the center of the orchestra section or nearer to the strings, or in a loge or a balcony seat.

My second group of listeners is also looking for the absolute sound, but with an essential proviso: These folks want to hear voices and instruments sound fully realistic when—and only when—the recording has been made in a way that permits them to sound fully realistic. This is what I call the “accuracy” school of listeners, who aren’t really listening first and foremost to music, but rather to the quality of recordings. Fidelity to what is on an LP or a bitstream becomes the central goal of the stereo system and reproducing what was actually miked, mixed, and mastered, warts and all, overrules other considerations.

The trouble here is that determining what was “actually” recorded is fraught with its own set of problems, not the least of which is the inescapable fact that a recording is made and monitored through a set of speakers (or headphones) and electronics that are fundamentally different than those through which that recording is being played back in your listening room.

Of course, you could (if you had the access) turn to someone who was actually at the recording session for an informed opinion on how “faithful” your playback is, but then you start bumping up against some of the same issues that vex absolute sound listeners (e.g., where was that audience member seated vis-à-vis the microphones used at the recording session—and how did what he or she heard differ from what the microphones heard at their locations, how reliable is his or her “sonic memory” of the event, how much of what he or she heard is actually reflected in the finished product where edits, compression, and overdubs may have been used, etc.).

Which kind of brings us back to the ineluctable relativity of the listening experience, in the concert hall, in the recording studio, and in the home—a conundrum that is solved (or at least overstepped) by my third group: the “as you like it” or “musicality first” listeners.

By far the largest of my three sets, musicality listeners are simply looking for a good time. They could care less if the system sounds like the absolute (save to the degree that voices and instruments sounding real increases their enjoyment of and involvement with what they’re hearing), and they aren’t concerned if a system is faithful to sources (save to the extent that better-sounding records make listening more exciting and fun). Truth is, this group is not interested in sound per se. Its adherents are interested in what sound does to them, physically, emotionally, and intellectually. They’re looking for a facsimile of the rapture they feel in a rock club or a concert hall; they’re looking for delight.

Obviously, the problem with putting musicality ahead of everything else is that one man’s musical is another’s mush. In worst case scenarios, musicality amounts to subjectivity taken to an entirely personal extreme. There can be no general standard of what constitutes excellent playback because no standard (except one’s own) is needed or applies. Put simply, you like what you like.

As I noted earlier, these three groups are interrelated: They share a love of “better” sound. What constitutes “better” is where they differ.

This brings me to a fourth set of listeners—one that Dr. Greene, at least in part, seems to sympathize with—the bunch that listens primarily to numbers.

Based on long experience, I don’t fully relate to this group. Oh, I understand the role that measurements play in designing, say, a loudspeaker, just as I understand the role that measurements play in following a recipe for a mille-feuille pastry or a plate of lièvre à la royale. What I don’t understand is how measurements taken with a microphone from one or even from several spots in an RFZ or an anechoic chamber or a quasi-anechoic setup can tell you, save in broad outlines, what that speaker is going to sound like in a real-world listening room, hooked up to real-world sources, amplifiers, and cables. For me, determining that requires actual listening, just as that pastry or plate of lièvre requires actual tasting.

I used to pester Harry with some of these thoughts—to get his goat. But whenever I started to go on about, say, the relativity of the absolute sound, he’d stop me short with a single prescient observation that could’ve been his byword: “We all know real when we hear it.” In other words, real is real, whether you’re sitting in the first row or the cheap seats, whether you’re listening to an RCA or a Mercury, whether you’re a fan of acoustic music or rock ’n’ roll.

“We all know real when we hear it.” Figuring out why that should be the case in the face of the obvious contradiction (to wit, a stereo system is manifestly not a real symphony orchestra or a string quartet or a rock group) has been the challenge of a hi-fi lifetime. And I haven’t figured it out yet, save to speculate (as I’ve done recently) that when a stereo sounds “real” it isn’t just a matter of superior parts (such as more powerful intensity, flatter-measuring timbre, longer duration, or more perfect pitch) but also of the way those parts are grouped together—of their gestalt—and that this magical gestalt regrouping of parts depends in some unmistakable way on the neutrality and completeness of the presentation. It is that neutrality and completeness that allows a stereo system to disappear like the Cheshire cat, leaving behind only the music—the cat’s grin.

Well, that’s it, folks. At least, from this corner of The Absolute Sound world. It may not be satisfying and it certainly isn’t specific, but…it’s the best I can do when it comes to summarizing how we listen.

Shunyata Research Everest 8000 AC Power Conditioner and Omega XC Power Cord

As a long-time user of various Shunyata Research AC power conditioners and power cords, I’ve been fascinated to discover how the company’s products have evolved with each new generation. In performance there’s been unmistakable forward progress, with lower noise and an attendant increase in clarity, resolution, and soundstaging. But Shunyata’s new flagship Everest 8000 power conditioner breaks this trend; rather than offering an incremental improvement, the Everest 8000 represents a significant leap in sound quality—one that redefines what’s possible in AC power conditioning.           I think it’s no coincidence that the Everest benefits from some of the technologies Shunyata founder and designer Calin Gabriel developed for his AC power conditioners used in medical laboratories. A few years ago, a cardiologist who spent much of his time battling residual noise while looking at extremely low-level electrical signals in heart patients made a surprising discovery. The cardiologist, an audiophile who happened to use a Shunyata power conditioner in his home-audio system, speculated that if the Shunyata conditioner lowered the noise floor in his music system, it might confer similar benefits in his medical lab.

After plugging his lab equipment into the Shunyata conditioner, he was surprised and delighted to discover that the AC conditioner allowed him to more clearly see the heart’s low-level electrical signals. He contacted Shunyata to share his experience, which eventually led Shunyata to start a whole new company, Clear Image Scientific, to design and manufacture AC power-conditioning devices for cardiac labs. The new company has grown exponentially, leading Gabriel to research and develop advanced new techniques to isolate, to an unprecedented degree, sensitive medical equipment from AC line noise. Some of those techniques have now been deployed in Shunyata’s AC conditioners for audio. How Clear Image Scientific sells its products says much about their efficacy; the company demonstrates the gear in a hospital for cardiologists, who can see for themselves the effect of reducing noise on the AC powerline.

Turning back to audio, the Everest is a vertical tower with a sloping front panel that narrows toward the top in a kind of truncated-pyramid shape (as seen from the front). This vertical form factor means the Everest sits on the floor next to your equipment rack rather than taking up shelf space. A blue LED, which is mercifully faint, indicates when the Everest is powered on. The rear panel holds eight AC outlets, each supported by Shunyata’s excellent cable-cradle system, which secures the AC cord to the power conditioner. An IEC C19 AC jack (20 ampere) accepts the AC cord that connects the Everest to your wall socket. The Everest isn’t supplied with this C19 cord; you need to provide your own. Because this cord essentially supplies your entire audio system, you’ll want to use a good one. Shunyata sent me its new Omega XC for this application, which costs nearly as much as the Everest ($8000 vs. $7000). An electromagnetic breaker switch turns the Everest on and off, but this switch is not a master power switch for your system. Rather, it is an over-current protection device. 

The Everest features Shunyata’s Ground-Plane Noise-Reduction (GP-NR) system, which consists of four grounding posts on the rear of the unit. The idea is that you run a wire from each of your components to the Everest’s grounding posts so that all your equipment is grounded to the same electrical potential. Although most components (preamps, DACs, servers, etc.) lack a grounding post, you can connect the ground wire to a chassis screw and achieve the same effect. Shunyata offers grounding cables made from flexible stranded wire that’s easy to work with. Ground posts are common on professional and telecommunications gear for good reason: If some of your components’ grounds are at a different electrical potential (voltage) than other components, and those components are connected through interconnects, a small amount of electrical current will flow along the ground path provided by the interconnect. We hear this current flow as noise and hum. Preventing these noise-inducing “ground loops” is why I specified that each run of 10AWG to the five dedicated AC lines to my listening room be of the same length. With identical-length runs, the ground potential will be the same in each line. It’s common in professional gear for every component in a metal rack to be grounded with a braided wire to the rack.


The Everest’s technology is based on that of the Hydra Triton and Typhon conditioners, but with some new twists in technologies, construction, and materials. Before describing the Everest’s design, we should review the goal of a power conditioner. In addition to distributing power to multiple components, an AC conditioner should block noise on the AC line from getting into your audio components. Most people think that this is a conditioner’s primary function. But a conditioner’s most important job is preventing noise from traveling from one component to another. Think of a digital component, filled with chips that switch high-speed digital signals on and off. This switching creates noise that gets on the component’s ground plane. The AC cords in your system are the conduits for that noise, conducting it from one component to all your other components, degrading performance. A good conditioner blocks and dissipates this noise, isolating the components from each other.

Each of the Everest’s eight outlets features Shunyata’s CCI (Component-to-Component Interface) filters—a series of multi-stage filters that removes noise. Noise is further reduced by Shunyata’s patented NIC (Noise Isolation Chamber), a device that contains a ferroelectric material that absorbs high-frequency noise. The NIC was originally developed for the Hydra Triton. A different type of noise filter, called “CMode,” reportedly reduces common-mode noise.

Another technology from the Triton/Typhon products is QR/BB, a circuit that delivers additional instantaneous current for brief transients, reducing dynamic compression. Unlike many conditioners that diminish the ability to deliver high-current pulses, QR/BB is claimed to increase impulse-current delivery via a circuit that lowers the inductive reactance. The Everest’s QR/BB device is three times the size of that in the Denali, Shunyata’s previous flagship conditioner. This feature is useful when power amplifiers or integrated amplifiers get their power through the Everest. Unlike a preamp or a DAC that draws a small amount of current continuously, a power amplifier pulls current from the wall in very short bursts (at the tops and bottoms of the 60Hz AC sinewave). If the conditioner restricts these instantaneous current surges, the amplifier will be starved for power, compromising musical dynamics. In designing the Everest, Shunyata relied on its proprietary test instrument, called the Dynamic Transient Current Delivery (DTCD) analyzer, to measure instantaneous current flow through low-impedance conductors and contacts.

The outlets are Shunyata’s CopperCONN, with contacts and conductors made from thick pieces of solid high-purity oxygen-free copper. They also provide better grip on the blades of an AC cord plugged into them than conventional AC outlets. I installed these outlets in each of the five dedicated AC lines that run to my listening room when I built the room. The Everest’s internal wiring is Shunyata’s ArNi conductors, made from certified OFE C10100 copper, and fashioned into hollow tubes to reduce skin effect. The conductors are treated with Shunyata’s KPIP (Kinetic Phase-Inversion Process), which reportedly eliminates the need for break-in, and improves the sound. Many of the components are cryogenically treated in Shunyata’s own cryo lab. Finally, the chassis and internal structures are treated with vibration-damping panels, and the outlets are physically de-coupled from the chassis for further vibration isolation.

I know that’s a mouthful of alphabet soup, but illustrates that the Everest is packed with technologies that Shunyata has developed over the past 25 years, many of them patented.

The Omega XC power cord features Shunyata’s VTX-Ag conductors that are made from an outer tube of purified copper surrounding a silver conductor. The cord has CopperCONN connectors encased in a carbon-fiber housing at both ends. Once assembled, the Omega XC is treated with the KIPP processing described earlier. Note that the step-up power cord, the Omega QR, incorporates noise-reduction technologies within the cable. Nonetheless, Shunyata recommends the Omega XC with the Everest. Both Omega Series cords are available in a range of carbon-fiber colors.

I replaced the Hydra Triton and Typhon combination that I’d been using for a few years with the Everest to power my front-end equipment. My equipment racks are at the back of the room behind the listening seat, and the power amplifiers are at the other end between the speakers. The power amps were plugged straight into the wall sockets.

When I’ve upgraded Shunyata’s conditioners in the past, I’ve usually heard an incremental improvement in dynamics, soundstaging, and the rendering of instrumental timbres. But the Everest/Omega XC combination realized, by far, the most significant improvement in my system. The change in sound quality was more of a step function than an incremental advance. It’s worth noting that my current system is extremely revealing of every change, good or bad.

Swapping in the Everest and Omega XC brought out the best in my system, heightening those qualities I value. The most immediate improvement was in the way the soundstage expanded in all dimensions, particularly in depth. Interestingly, the entire stage became slightly less forward and immediate, like moving from Row C to Row M. But at the same time, the spatial presentation became more three-dimensional, with instruments toward the back of the stage sounding much farther away. The apparent distance between instruments in the front and back of the orchestra expanded. A few minutes into The Rite of Spring (Eiji Oue, Minnesota, Reference Recordings, MQA at 176.4kHz) a contrabassoon plays a short, virtually unaccompanied passage. The Everest presented the instrument as way back in the orchestra, with very fine resolution of the reflections and reverberation that supply the brain with distance cues. Despite the slightly less immediate spatial perspective, the sense of vividness and tangibility increased.

But that’s not what make the Everest/Omega XC so compelling. Rather, it was the way this new conditioner resolved the air and space between instruments, giving the sound a greater dimensionality that was closer to what one hears from live music. I could hear a more tangible sense of the cushion of air around each instrument, particularly on dynamic passages. The feeling of sound expanding from the instrument was more realistic. This impression was heightened by the tighter focus of the image itself, along with the greater delineation between the image and the air around it. This may sound like an esoteric analysis of a not-that-important perception, but this more realistic portrayal of instrumental images, the immediate space around them, and the greater space of the hall went a long way toward making me forget I was listening to a recreation of music. It was just more organic and lifelike. In addition, the finer spatial resolution and more vivid presentation of individual instruments made it easier to follow each instrument’s musical line within the whole. The track “The Cowboys Overture” from John Williams at The Movies (176.4/24 downloaded from Reference Recordings) took on much more sonic and musical clarity, with each instrument, section, and musical line more clearly resolved.

I’ve noticed that my colleague Andrew Quint mentions in his reviews a track that I also happen to like, and also use in evaluating equipment. “Back Row Politics” from Gordon Goodwin’s Big Phat Band Act Your Age features three virtuoso trumpet players trading off extended, high-energy solos. After adding the Everest to my system, the trumpets had less glare, along with more richness, warmth, and body.

Finally, I heard an increase in dynamic impact, particularly in the bass. This is one of my system’s strong suits, but the Everest took transient fidelity and visceral impact to another level of realism.

The Everest 8000 AC conditioner and Omega XC power cord are, in my view, the best components to come out of Shunyata Research, a company with a long history of developing great products. The Everest allowed the outstanding components in my system to perform at their highest level by providing them with an ultra-quiet and clean power source. The Everest 8000 and Omega XC have become essential parts of my reference system.

Specs & Pricing

Everest 8000
Type: Eight-outlet AC conditioner
Maximum continuous current: 30A (US version)
Maximum continuous current per outlet: 15A (US version)
Isolation zones: Six
Noise suppression: Input to output (100kHz–30MHz): >50dB reduction; zone-to-zone (100kHz–30MHz): >60dB reduction
Over-current protection: Hydraulic electromagnetic breaker
Wiring: 8 -gauge ArNi® VTX™ Buss system; 10 gauge ArNi® VTX™ wiring
Dimensions: 8″ x 20.75″ x 14.75″
Weight: 34 lbs.
Price: $8000

Omega XC Power Cord
Technology: VTX-Ag conductors
Price: $7000

26273 Twelve Trees Lane, Ste D
Poulsbo, WA 98370
(360) 598-9935

Associated Equipment
Loudspeakers: Wilson Audio Chronosonic XVX, Wilson Subsonic subwoofers (x2), Wilson ActivXO crossover
Analog source: Basis Audio A.J. Conti Transcendence turntable with SuperArm 12.5 tonearm; Air Tight Opus cartridge; Moon 810LP phonostage; DS Audio ST-50 stylus cleaner
Digital source: Aurender W20SE and Wadax Atlantis servers, Berkeley Audio Design Alpha DAC Reference Series 3 and Wadax Reference DACs; Berkeley Alpha USB USB-to-AES/EBU converter; Shunyata Sigma USB cable; AudioQuest Wild Digital AES/EBU cable
Amplification: Constellation Altair 2 preamplifier; Constellation Hercules 2 monoblock power amplifiers, Constellation Centaur 2 stereo (driving subwoofers)
AC Power: Five dedicated 20A lines terminated with Shunyata AC outlets
Support: Critical Mass Systems Olympus equipment racks and Olympus amplifier stands; CenterStage2 isolation
Cables: Shunyata Sigma interconnects; AudioQuest WEL Signature interconnects; AudioQuest Dragon Zero and Dragon Bass loudspeaker cables
Acoustics: Acoustic Geometry Pro Room Pack 12
Room: Purpose-built; Acoustic Sciences Corporation Iso-Wall System
LP cleaning: Klaudio KD-CLN-LP200, Levin Design record brush

2021 Jeep Grand Cherokee Ushers in Luxury Sound by McIntosh

The following is a press release issued by McIntosh.

BINGHAMTON, NY (January 7, 2021)The new 2021 Jeep Grand Cherokee, now with three rows of seating, will debut with the auto industry’s only sound system made by the legends in luxury home audio, McIntosh Laboratory. Available first in the 2021 Jeep Grand Cherokee L, the MX950 McIntosh Entertainment System is available in Overland and Summit models and comes standard when equipped with the Summit Reserve Package.

The collaboration between McIntosh and the Jeep brand has been a match made in America. The Jeep brand understands McIntosh’s goal is to carry its exceedingly high standards for sound into vehicles in an authentic way. That said, this partnership didn’t happen overnight.

Seeds for MX950 McIntosh Entertainment System for the Jeep Grand Cherokee were planted four years ago when engineers from both organizations collaborated on the Grand Wagoneer concept vehicle revealed this past September.  And now with the Jeep Grand Cherokee L, customers will soon be able to experience what it is like having a McIntosh Entertainment System with them on-the-go.  It is sure to be “Legendary Performance in Motion.”

For over seven decades, McIntosh has been on the leading edge of high-end home audio and popular culture with sound systems handcrafted in their factory in Binghamton, NY. The company’s amplifiers were used to power the original Woodstock and the Grateful Dead’s groundbreaking “Wall of Sound” which cemented McIntosh’s reputation as a true American icon.

But McIntosh is no stranger to car audio, having delved into both OEM and aftermarket fitments in the 1990s. In the new millennium, McIntosh developed custom solutions for Harley Davidson special editions, and the 100th anniversary edition of the Ford GT. The MX950 McIntosh Entertainment System for the Jeep Grand Cherokee will take sound quality to the next level, much the same way Jeep Grand Cherokee has repeatedly reset the bar in sport utility vehicles.

“We understand that customers don’t just want great sound,” said Charlie Randall, President of McIntosh Laboratory, Inc.  “They want to get a full sensory experience.  And that’s why it was so important that we left no stone unturned to deliver a true McIntosh Entertainment System for the Jeep Grand Cherokee L. We’re thrilled to bring our brand to a whole new group of people who may never have experienced McIntosh before.”

To ensure McIntosh luxury home audio experience was replicated in the vehicle, engineers from both companies worked hand-in-hand to fuse form and function into the system architecture. Engineers constantly went back and forth between the test vehicle and the McIntosh Reference Room itself to ensure a truly authentic McIntosh experience, even in a car. The resulting system is so revolutionary, it doesn’t just bring the performance to you, it brings you to the performance.

The MX950 McIntosh Entertainment System boasts 19 speakers in 12 optimal locations to deliver precision sound through every inch of the vehicle and a 17-channel amplifier delivers up to 950Watts of power. The system has LD/HP® speaker design to lower distortion and McIntosh Power Guard for unrivaled clarity even at very high-volume levels. The most advanced materials technologies were used to make components lighter, yet stronger, so speakers respond faster in delivering timely sonic reproduction. The occupants are enveloped in a massive sweet spot to hear music with zero coloration, just as the artist intended.

The shared vision between Jeep and McIntosh was to integrate the same level of authenticity and design language from the McIntosh home audio products into the Jeep Grand Cherokee.  The system incorporates McIntosh’s iconic styling cues such as the metal ridged control knobs, in the look and feel that have made McIntosh instantly recognizable to fans around the world.   Backlit logos on the door speaker grilles accent the vehicle’s interior lighting with McIntosh’s signature blue. The Jeep Grand Cherokee L’s subwoofer grille is emblazoned with the McIntosh “Mc” logo as it appears in McIntosh Monogrammed Heatsinks™.  It is truly a treat for the eyes as well as the ears!

The 2021 Jeep Grand Cherokee L is equipped with the MX950 McIntosh Entertainment System and will arrive in Jeep dealerships in the second quarter of 2021.

UpTone Audio EtherREGEN Ethernet Switch

With the increasingly widespread streaming of digital music content to our audio systems, either from discs or streaming services (e.g., Tidal or Qobuz), many audiophiles are finding the need for an audio-grade Ethernet switch to connect their home computer network modems, routers, computers, drive arrays, etc. to an increasingly wide array of devices to mediate the transfer of digital content to digital-to-analog converters. As my digital streaming “front-end” has been in development for the last year and half or so, I’m finding there are now better audiophile-grade solutions that provide network access to my nearly 4TB of disc-based digital content, and to new content via streaming services.

UpTone Audio is a small audio-products firm based in Northern California. Company principal and founder, Alex Crespi, has been in the audio business for over 30 years, and was one of the co-founders of the well-regarded audio products company, Hovland, which was started in 1999 and closed in 2009. UpTone was founded in 2010, and all of its products are developed in close partnership with professional electronics engineer, John Swenson, who has had a long career designing the power-distribution networks deep inside large custom computer chips (the sort of devices that run high-speed network data centers). As UpTone Audio, Crespi and Swenson have developed a successful range of products for digital playback including the REGEN line of digital audio products and the UltraCap line of linear power supplies for digital components and music servers. John is also well-known as the hardware engineer for the popular Sonore Rendu series of products.

I purchased my $640 UpTone Audio EtherREGEN in October, 2019, and I can unequivocally say it has been instrumental in getting the audio performance of my digital streaming front end to a level where it is now as fully engaging, immersive, and enjoyable a musical experience as my turntable-based analog system.

Description and Features
The UpTone Audio EtherREGEN Ethernet switch utilizes the same oval-shaped aluminum case used for many UpTone Audio products, and measures 112mm x 110mm x 30mm. Of note, UpTone has specifically designed EtherREGEN so that it does not require an external linear power supply to provide nominal performance. Rather, it comes with an UpTone Audio switch-mode power supply specially designed to prevent the passage of high source-impedance leakage current to the EtherREGEN (more on this later).

The EtherREGEN is unique among Ethernet switches in that it uses a circuit topology called the Active Differential Isolation Moat or ADIM that completely isolates the side of the switch used for connecting network devices (typically the “A” side) from the side connected to the renderer, network bridge, or streamer (typically the “B” side). The ADIM provides electrical, galvanic, and noise isolation between the two sides. I’ll discuss the rationale and function of the “moat” in more detail in its own section in this review.

On the “A” side of EtherREGEN is a SFP (small form-factor, pluggable) cage for making fiber optic connections using an optical transceiver (Figure 1) and an RJ45 module composed of four specially manufactured copper Ethernet ports with status lights. There are 12 transformer cores in each port and the center-taps of these cores are grounded using capacitors to block port-to-port leakage current.

EtherREGEN B Side

The “B” side of EtherREGEN (Figure 2) has a DC-power barrel jack, ground post, a single 100-Megabit RJ45 port with status lights, a switch for selecting the internal or an external clock, and a BNC connector for connecting an external clock, if hot-rodding your EtherREGEN is desired. The standard impedance for the clock connector is 75-ohm, but a 50-ohm clock connection can be ordered from UpTone Audio at no additional charge. While EtherREGEN works identically in both directions, the “B” side is typically connected to the computer, streamer, network bridge, endpoint renderer, etc., with a copper Ethernet cable. DACs that have an Ethernet input can be directly connected to the “B” port.

Technical Considerations and Design Features
The Active Differential Isolation Moat (ADIM) design is unique to the EtherREGEN, as it provides data-transfer functionality and audio performance that significantly differentiates it from all other Ethernet switches, including those modified for audio applications. EtherREGEN has two data/power/clock domains which are isolated from each other by the ADIM. These two domains are referred to the as “A” side and “B” side, respectively. Each isolated domain is re-clocked, and the clocking system runs from an advanced, programmable, jitter-attenuating clock synthesizer with four differential outputs. It is referenced to an ultra-low-jitter/phase-noise Crystek CCHD-575 oscillator, and the clock distribution system is run differentially throughout. UpTone Audio colloquially refers to the separation provided by the ADIM between the sides of its circuit board as “the moat.”

The rationale for the moat is important because every signal “edge” coming out of any digital device carries the jitter and phase-noise of the clock used to “clock out” that edge. When dealing with Ethernet-based signals, specifically for audio applications, where timing is critical, there are two types or classes of sound-degrading noises that EtherREGEN was designed to mitigate: 1) low and high source-impedance leakage current, and 2) clock phase noise. Clock phase noise travels on the Ethernet signal and on power and ground planes. This phase noise affects the threshold jitter of chips’ clock inputs.

The differential circuitry was specifically designed to eliminate the signal-borne phase noise going from one side of the moat to the other. EtherREGEN is mostly symmetrical—technically, there is no “dirty side” or “clean side.” While ER works identically in both directions, it is best to have the streaming endpoint device (renderer/streamer/network bridge) that connects to the DAC be the only device that is connected to that particular side (typically the “B” side). While the circuitry between the individual RJ45 ports or SFP cage on the “A” side decreases phase-noise effects to some degree, it does not decrease it to the same degree obtained by crossing the moat. This is because crossing the moat makes use of differential isolators in conjunction with differential flip-flops. (Refer to the engineering white paper by John Swenson, Understanding how perturbations on digital signals can affect sound quality without changing bits, and how these issues are addressed by the UpTone EtherREGEN, https://cdn.shopify.com/s/files/1/0660/6121/files/UpTone-J.Swenson_EtherREGEN_white_paper.pdf?v=1583429386.) And this is the big advantage: The differential isolators prevent the data-borne clock signature from getting onto the ground plane of the circuit board, while the differential flip-flops prevent the clock phase-noise signature from getting into the flip-flop’s own internal ground network, as well as the ground plane of the rest of the board. It is the use of these two differential isolation methodologies together that provides the performance advantage of EtherREGEN compared to other Ethernet switches.

Physically, EtherREGEN circuitry is mounted on a single, premium, six-layer circuit board, but electronically it is actually two boards (Figure 3). Looking at the EtherREGEN circuit board, we see it is galvanically divided into two parts, the “A” side (lower half of Figure 3) that typically handles network connections, and the “B” side (upper portion of Figure 3) across the moat, which provides the fully isolated signal to the renderer/endpoint.

Transfer of data from one side to the other is mediated using high-speed Analog Devices differential isolators. When the network signal has passed to the other side of the moat via the differential isolators, it is sent to the “B” side electronics that re-clock the data with an ultra-low phase noise Crystek CCHD-575 Crystal oscillator and Silicon Labs jitter-attenuating clock synthesizer (unless the clock switch is set to external, in which case, the external clock signal is used).

This is a key point: Because all the clocking in EtherREGEN is run with differential lines, and the isolators and flip-flops are fully differential, there is no noise overlaid on EtherREGEN’s ground plane by any of the el-cheapo clocks from network devices (e.g. routers, music servers, NAS’s, generic switches, etc.) upstream. Furthermore, no leakage current from switch-mode power supplies from these upstream devices can pass across the moat, either. No other Ethernet switch design does this, and these features are key aspects of EtherREGEN’s unique design because they prevent the data-borne clock signature and leakage currents from getting onto the ground plane of the circuit board and into the DAC, where they will increase jitter in the circuitry. Reduction of phase noise, leakage current, and concomitantly, jitter, are the significant audible benefits that EtherREGEN offers when used in a digital music streaming setup.

Set-up and Configuration
The setup and configuration of EtherREGEN is simple and straightforward. Connect a single copper Ethernet cable from their main network router or switch to any of the RJ45 ports on the  “A” side (Figure 4) of EtherREGEN. The remaining three RJ45 ports can be used for other connections, e.g. a music server, NAS, or other network device. If an optical-fiber connection is used, it can be connected to an optical transceiver in the SFP cage on the “A” side. 

Depending on the user’s network or requirements, different connection configurations are possible. For example, one could leave the network router music server, NAS, etc. connected to another switch, and make a single Ethernet connection to EtherREGEN as shown in Figure 4. How the connections are configured are primarily a matter of convenience and/or the requirements of the specific network, and UpTone says the effects of different configurations on sonic performance are likely to be small, if any.

Networking Setup for Evaluation
I made my evaluations of the EtherREGEN compared to a consumer-grade TP-Link Ethernet switch, as I did not have access to any other “audiophile-grade” Ethernet switches. Since I am using a run of fiber from the bedroom study, where the music server, router, and switches are located, to the main audio rack, I also used a consumer-grade TP-link fiber-media converter (FMC) in conjunction with the TP-link Ethernet switch. It’s important to understand that the base configuration was composed of two networking devices used together to stream the data: the consumer Ethernet switch and a fiber-media converter. The run of fiber connected at the downstream end in the main audio rack to a Sonore Optical Module that was connected by a Shunyata Sigma copper Ethernet cable to my SOtM SMS-200 UltraNeo network bridge, which serves as my endpoint/renderer, as shown in the base networking configuration in Figure 5. 

For my configuration with EtherREGEN, I replaced the generic TP-link FMC with the Sonore OpticalModule at the upstream end; the Mac Mini music server and OpticalModule were connected to the RJ45 ports on my network router with Shunyata Sigma Ethernet cables. The OpticalModule was connected with a forty-foot run of optical fiber downstream to EtherREGEN’s “A” side via it’s SFP cage in my main audio rack. A Shunyata Sigma Ethernet cable from the “B” side of EtherREGEN was connected to my SOtM SMS-200 UltraNeo renderer/endpoint, which was connected to my Schiit Gungnir Multibit DAC with a Shunyata Alpha USB cable. The configuration using EtherREGEN is shown in Figure 6.

Power Connections for Network Devices
Because of the insidious and audible problems of leakage current, caused by the use of switch-mode power supplies in virtually almost all network devices, I paid special attention to the quality of power for the devices in the digital streaming chain. In my base configuration, when the TP-link Ethernet switch and FMC were used, they were powered by Jameco Reliapro linear power supplies; my Pace router used its standard switch-mode power supply with a home-made connector that shunts high source-impedance leakage current to ground. For the purposes of this review, the Mac Mini music server was powered with a Shunyata Venom V14D digital power cord, and the Sonore OpticalModule was powered with an UpTone Audio LPS-1 power supply. Both the UpTone LPS-1 and the Mac Mini were plugged into a Cryoparts power strip powered by a Shunyata V12 NR power cord. The Shunyata V12 NR power cord provides approximately 12dB of noise reduction for the power strip, and the Venom V14D digital power cord, specifically designed for devices that utilize switch-mode power supplies (e.g. the Mac Mini), provides another 12dB of noise reduction. In the main audio rack, the EtherREGEN was evaluated using the supplied UpTone Audio power supply, and the SOtM SMS-200 UltraNeo endpoint renderer was powered by a Keces P3 linear power supply. Both of these power supplies were powered by Shunyata Venom V14D digital power cords plugged into a Shunyata Everest power distributor. All listening evaluations were conducted using my two-channel loudspeaker system described in the addendum.

Listening Impressions
My journey with my digital streaming front end has been one of discovery, experimentation, and reflection. This journey has taught me new ways to listen to digital content that are much more convenient, flexible, and enlightening, specifically when I use the Radio mode of Roon and Qobuz to discover new music. While I was reasonably satisfied with my first digital front end, when I made the decision to run a direct optical fiber cable connection from the music server to the DAC (see my article on streaming via optical fiber in the May issue of TAS), I needed an Ethernet switch. I bought a generic, consumer-grade TP-link switch to connect the router, music server, and my fiber media converter to the network. After installing it, there were aspects of the presentation that I just didn’t like. Upon first listen, the TP-link switch brought improved detail, but upon extended listening it also brought other attributes were very decidedly un-musical.

What I found was, despite the increased detail, there were “components” to the music and presentation that became increasingly irritating, fatiguing, and over longer listening sessions, quite unpleasant to listen to. I found that I couldn’t listen to the system for more than an hour without wanting to leave the room. It turns out that my Pace network router had four RJ45 ports on it, and I found that by not using the TP-link Ethernet switch (and just using the RJ-45 ports in my router) the presentation was actually pretty good. I would have thought that installing a dedicated Ethernet switch should have sounded better than the ports in a generic Internet router, but every time I put the TP-link switch back into the network (regardless of recording) the system sounded…ghastly. Harsh, strident, bright, irritating, with shrinking of the soundstage and spatiality, a crushing down of dynamic range, and a loss of nuance and gesture in the artists’ singing or playing. By contrast, I found when just using the router’s RJ-45 ports to make connections the sound was acceptably good; I’ll circle back to this observation in the conclusion.

Installing the EtherREGEN Ethernet switch into the system (Fig. 6) brought a significant improvement to the system overall—so much so that it doesn’t even sound like the same system compared to the base configurations. I heard these improvements immediately upon installation, but also noted that, as with almost every other component I’ve owned, audio performance was a bit uneven for the first 200 hours. After that burn-in period, EtherREGEN really smoothed out tonally and opened up spatially with a very low noise floor, providing an exceptionally clean space for the music to emerge into. Most importantly, there was virtually no digital glare, hash, or other nasties that induce listener fatigue. Rather, the presentation was organic, relaxed, and natural to the degree that my digital streaming front end fully rivaled my analog setup.

With EtherREGEN in the system, the Spanish guitar solo fantasia “Malagueña,” composed by legendary guitarist Celedonio Romero, and performed by his son Pepe Romero, had incredibly energetic pacing, a fulsome woody timbre, and finely delineated harmonic structures, as Romero ripped his way through this classic with stunning virtuosity and impeccable technique. There was so much resolution and definition and sheer virtuosity on display that, the first time I heard it, I thought two guitarists, Celedonio and Pepe Romero, were playing…but no, it was just Pepe. As he is the only musician, the stereo image is precisely focused on Romero, but the trailing edges of notes can clearly be heard decaying into the space of the room. Romero moves from a forceful, fast, and dynamic passage to a very beautiful slow, refined, and delicate passage with exquisite phrasing, nuance, and control, and you can hear deeply into the recording, the subtle shadings of timbres and notes flying with perfect articulation off the sound box of his guitar. It was dazzling and incredibly beautiful.

“Falling out of Love” by Mary Gauthier (Mercy Now), is skillfully recorded and mastered with a rich tapestry of sounds, from Gauthier’s gruff voice to her clear, sonorous, and pitch-perfect acoustic guitar in counterpoint to a background harmonica, all fully grounded by a bass drum with a steel guitar layering a plaintive whine on top. Everything comes together as a darkly beautiful song, full of pathos and loss. One of the things that I heard for the first time with EtherREGEN was the gourd instrument, the shakere, driving the rhythm forward, fully resolved but played with just enough restraint not to overpower Gauthier’s voice.

The timeless standard “Cry Me a River” with bassist Ray Brown (Soular Energy) featuring Gene Harris on piano, was beautifully presented with a deep black background against which Brown’s finely articulated string bass provided counterpoint to Harris’ exquisite piano playing. This is one of the most natural and organic-sounding jazz recordings I’ve ever heard, and the clean and quiet background provided by EtherREGEN let the simple beauty of the mastering shine through with subtlety, texture, and naturally rendered tone colors from the piano and bass.

I’ll have to admit I haven’t followed Adele’s studio recordings all that closely—a bit too much commercial overexposure for my sensibilities—but the first time I heard her live recording of “Lovesong” (Adele: Live at the Royal Albert Hall) on my Harbeths, I was smitten. With an exquisitely beautiful vocal performance by Adele, “Lovesong” is exceptionally well-recorded and mastered for a live recording in a large venue. Its starts with the two guitarists, Ben Thomas and Tim Van Der Kull, left and right, and Miles Robertson’s organ laying out the melody and rhythm as her voice comes in over the top, followed by the crispness of Derek Wrights’ drumming and the swell from the string section. The song builds and develops slowly and beautifully as Adele’s incredible voice, finally set free, soars above the string section. It is an absolute knockout. The feel, ambience, and atmosphere of an outstanding live performance in front of a enraptured audience is captured on the recording, and listening to it with EtherREGEN in the system I felt as if I could dive into the experience along with the audience.

After 40 years as an audiophile, I’ve never tired of listening to J.S. Bach’s Concerto for Two Violins, strings, and continuo in D Minor, particularly when Belgian violinist Arthur Grumiaux is playing, as he is on the Decca recording with Les Solistes Romands. Here Grumiaux used his Guanerius violin, Rose, made by Giuseppi Guaneri in 1744. All the classic Guarnerius violin attributes—richness, sonority, timbral weight, and exquisite tone—are in full evidence, and in Grumiaux’s hands the virtuosity is fully resplendent, bright, and energetic, never harsh or strident. Each musician in the chamber orchestra is precisely positioned in the soundstage, and with the inner detail and spatial accuracy that EtherREGEN brought, you could focus in on each instrument in the orchestra and hear it fully resolved against the background of the orchestra as a whole. For example, during the Allegro on Concerto No. 2 for Violin, strings, and continuo in E Major on the same recording, as Grumiaux winds down a solo, I could clearly hear the first cello come in on the right, providing counterpoint to Grumiaux’s violin.

A recent find from Roon’s Radio mode and Qobuz is Yeol Eum Son and The Academy of St Martin in the Fields, playing Mozart piano concertos. In particular, Piano Concerto No. 21 in C Major (“Elvira Madigan”) is a standout. Son’s sweet, light touch and virtuosic technique remind me of Julian Katchen, and give full credit to Mozart’s genius as well as his musical “sense of humor” in this, his most popular piano concerto. The vibe that comes across is that the musicians are having an absolute blast playing this delightful concerto. This is most evident in Movement III: Allegro Vivace Assai; where both Son and the Academy engage in the classical music version of “call and response,” both pianist and orchestra playing with incredible speed, delicacy, and touch in this challenging movement, the woodwinds cleanly interlaced with the piano. The piano’s full dynamic range, power, weight, and timbre were evident, yet resolved and defined, as were the contributions of every musician and instrument in the orchestra. A fabulous recording by Onyx Records, Son and the Academy’s world-famous super-clean, super-light, and super-tight playing is sensational. Just a fantastic recording and performance.

As I mentioned in Listening Impressions, my journey with developing my digital streaming front end and the UpTone Audio EtherREGEN has been an interesting and informative one. I’ve learned that digital streaming, either via a music server or a streaming service (especially Roon), has clear advantages with respect to accessing and listening to digital content. But, as we add more networking devices to take advantage of the convenience, functions, and features, there is a price to paid. Every consumer-grade digital device with el-cheapo clocks (powered by those dastardly switch-mode power supplies) that we add to our streaming network is adding more clock phase noise, leakage current, and noise on the ground planes of our endpoints and DACs, thereby increasing threshold jitter and, concomitantly, timing errors. The reason for this is explained in John Swenson’s White Paper for EtherREGEN referenced above:

“What this clock phase-noise overlay looks like depends upon the clocks and circuits involved. Most ‘residential’ network devices have very cheap oscillators with very high phase noise, so effects from this in the combined clock can be very strong. Therefore, if your endpoint has a very good local clock, the overlay from upstream can be significantly greater than the local clock.”

When I understood this, it became clear why I couldn’t bear to listen to the system after I added the TP-Link Ethernet switch into the configuration: The digital nasties from it were overlaid onto those already present from the other upstream networking devices (router, FMC, and music server). This additional overlay pushed things over the top for me, creating too much of a bad thing. And this is where EtherREGEN rushed in like the cavalry and saved the day, changing the audio experience from one that previously drove me from the room to one that became completely engaging, compelling, and beguiling.

In summary, I consider the UpTone Audio EtherREGEN to be both a breakthrough and a landmark audio product. If you have, or are looking to put together, a music-server-based digital streaming front end, and you need an Ethernet switch in your network, the EtherREGEN deserves serious consideration. Mine has provided me with the convenience, access, and functionality of Roon with curation of content of Qobuz. And, in doing so, it provides a musical experience that’s every bit as engaging and compelling to listen to as my analog system. At only $640, it’s got to be of the biggest value propositions in all of high-end audio, and has my highest possible recommendation.

Specs & Pricing

Circuitry: Fully differential clock circuitry, isolators, and flip-flops
Clock system: Ultra-low jitter/phase noise Crystek CCHD-575 oscillator
Power regulation: Linear Technology LT3045 and LT3042 voltage regulators
Operating Temperature: 48-52° C (118-126° F
Dimensions: 112mm x 110mm x 30mm
Weight: 298 grams (10.5 oz)
Price: $640

Associated Equipment
Digital sources: Schiit Gungnir Gen 5 USB Multibit DAC, SOtM SMS-200 UltraNeo network bridge, Mac Mini Roon Core Server, Sonore OpticalModule fiber media convertor, UpTone Audio EtherREGEN Ethernet switch, UpTone Audio LPS-1.2 and Keces P3 linear power supplies.
Analog source: Michell Gyro SE turntable, SME V tonearm, Koetsu Urushi Vermilion cartridge, Bob’s Devices Cinemag step-up transformer, Uni-Pro protractor
Phonostage: E.A.R. 324
Preamplifier: First Sound Presence Deluxe 4.0Si Mk-III dual mono preamplifier with dual mono external power supplies.
Power Amplifier: Conrad-Johnson LP70S
Loudspeakers: Harbeth 40th Anniversary 30.2, Dynaudio Contour S3.4 with Esotar 2 tweeters, REL R-305 sub
Cables: Shunyata Research Sigma XC (Everest), Sigma NR V2 (power amp), Alpha NR V2 (preamp), Venom NR-V10 (DAC), Venom V14D Digital (digital components), Black Mamba CX (phonostage) power cables, Shunyata Research Delta and Venom interconnects, Shunyata Research Sigma Ethernet & Alpha USB digital cables and Shunyata Research Delta V2 VTX-Ag speaker cables
A/C Power: Shunyata Research Everest power distributor and SR-Z1 wall outlet

Maria Schneider’s Data Lords

Three summers ago, Grammy Award-winning composer-arranger-bandleader Maria Schneider premiered her darkly dystopian piece “Don’t Be Evil” at the 2017 Newport Jazz Festival. A swirling, foreboding paean to the sheer power and dominance of tech giant Google, it was named for the company’s motto and corporate code of conduct and carried a couple of tongue-in-cheek references to the military bugle call “Taps,” a song usually played at funerals. This was the outspoken artist sounding the alarm, and she ran down a laundry list of Google’s evils to the Newport crowd—addicting kids to its services, controlling our choices by manipulating “search,” gathering and selling data to garner endless power and money—before her award-winning orchestra launched into the heady commissioned work. And with electric guitarist Ben Monder rampaging through the fray of dissonant horns with a distortion-laced barrage of skronking to rival vintage Sonny Sharrock with Pharaoh Sanders, this dramatic highlight of the Maria Schneider Orchestra’s set was as compelling as it was scary.

At the time, “Don’t Be Evil” stood as an uncharacteristically heavy piece in Schneider’s otherwise uplifting oeuvre—just something she had to get off her chest and onto the page. Over time, however, as her writing progressed, themes started to emerge until it became clear that she had a full-blown concept album on her hands. The imposing Data Lords, Schneider’s latest ArtistShare release, is a double CD set —one composed of dark themes and edgy electric tunes representing The Digital World, another containing warmer, uplifting, often whimsical themes representing Our Natural World. And while the seeds of this project may have been planted with the premiering of “Don’t Be Evil” three years earlier at Newport, Schneider explained, “I hadn’t thought about recording it back then. I was just writing music and continued to write new pieces. And then about a year and a half ago I began to envision a double CD that is telling the story of the push and pull of what we all live with now. Once I was conscious of that, it helped me then find my way.” 

In Schneider’s “divining rod” process, she writes the music and then lets it guide her to some conclusion. “I just let the writing of music and the sounds lead me and my thoughts and my interpretation of those sounds,” she explained. “And then all of a sudden you realize there’s sort of a theme or a way to tie it together that reveals itself. I can probably count on one hand the number of pieces where I actually set out with an intention to try to create something about something. It almost doesn’t ever exist with me.”

What revealed itself to Schneider along the way was the idea of depicting the dichotomy between dark and light, digital and natural. And while “Don’t Be Evil” and other turbulent, electrified fare like “Data Lords” and the ominous “A World Lost” fit the bill for The Digital World, the gentle, hymn-like ‘Sanzenin,” the sparse and playful “Stone Song,” the warmly lyrical “Look Up,” and the summer tone poem “BlueBird” fit nicely into Our Natural World. Two other songs in the natural collection, the delicate and poignant “Braided Together” and the wistful “The Sun Waited for Me,” were instrumental pieces inspired by poems from the Pulitzer Prize-winning Great Plains poet Ted Kooser. Composing instrumental music based on poems, Schneider explained, is a different realm. “You’re following another expression. The words are guiding you already with the melody, the phrasing of the sentences, the intent behind the words. It’s different than coming up with an idea in space in your own head and saying, ‘Okay, now I’m going to write about this.’ In the end, they are instrumental pieces that I would’ve never written without the poetry. The poems made me write in a way that I wouldn’t write otherwise too.”

Schneider explained that her walk on the dark side in The Digital World portion of Data Lords was inspired by her collaboration with David Bowie in 2015 on “Sue (Or in a Season of Crime),” which later resurfaced in a tougher, pared down version on Bowie’s final album, Blackstar. “Working with David made me realize that dark can also be fun. And I think that quality came into play on this album too. I wasn’t scared to go into that dark place on intense things like ‘Don’t Be Evil’ and ‘Data Lords’ because I sort of reveled in the fun of it. There’s a little bit of humor or sarcasm in those pieces that I also enjoyed. I didn’t sit here seething as I wrote this music. As a matter of fact, I had more fun than I think I’ve ever had because it felt like such a release to put that in the music.”

HEGEL Launches V10 Phonostage

The following is a press release issued by Hegel.

January 2021 – Hegel Music System AS is proud to announce the launch of our first ever phono stage. Say hello to the V10.

We have often been questioned when we will bring out a phono stage.  For years we answered; “no, we will never make a phonostage”. Later we gradually changed it to; “forever is a very long time, but I don’t think we will make a phonostage”.

But as people keep saying – these are extraordinary times – so here is the Hegel V10. A phonostage we have become extremely proud of.

MSRP/RRP: EUR 1,395 / USD 1,500 / GBP 1,350
Ships: Mid February
Size: Half with
Sound: Extremely good
Web: https://www.hegel.com/products/phono/v10


The V10 is an attempt to make the style of design and sound performance of a EUR/USD 3,000 type RIAA in a half priced package. Therefore the V10 is designed with fully discrete input stages using some very special hand matched pairs of FET transistors. Both for the MC and afterwards the MC stages. This ensures very low noise and zero DC feedback to the pick up. After the FET stages a new bipolar opamp stage takes over for optimal amplification.

Further, the V10 is 100% dual mono design. It uses an external AC power supply that is specially designed by Hegel for the V10. This power supply has two connectors. One for each channel feeding in to the V10. The main features here is a very low noise floor and optimal channel separation. The internal power supplies are also shielded heavily from the gain stages.

In our, perhaps not so, humble oppinion the V10 brings forward all the classic Hegel virtues. Dynamics. Resolution. Naturalness. Finally also for vinyl lovers.

Ideon Audio Absolute Digital-to-Analog Converter

What does it really mean to say that a luxury consumer good is a “no compromise” product? Sometimes, it means you’re getting the top-of-the-line model with as many bells and whistles as possible. You drive home in a loaded Cadillac Escalade—the Sport Platinum version with plenty of extras, including 22″ 12-spoke chrome-alloy wheels and a polished exhaust tip. The same paradigm can hold with an audio purchase. You go for the preamplifier with the optional phonostage, the server with the standard USB card replaced by one with more impressive specifications, the high-gloss paint finish (in a custom color) that added several thousand dollars to the cost of those already expensive loudspeakers. But other times, “no compromise” refers strictly to basic performance: Nothing is included that could possibly degrade sonic quality. Less is more. This was very much an issue on the table as I got to know Ideon Audio’s $34,900 Absolute digital-to-analog converter.

Ideon is based in Athens, the locus of Greece’s small but vital audiophile community. It’s been operating since 2016, co-founded by the company’s chief engineer Vasilis Tounas and its CEO George Ligerakis, an IT professional. Other principals include Angelos Gallis, representing Novatron SA (a firm assisting with logistics, importing, and accounting) and Greg Mitsacopoulos, the Operations Director and marketing maven. The four are close friends and, while all are highly qualified for their roles in this endeavor, Ideon Audio is also clearly a labor of love. Ideon’s first product was the Ayazi DAC, now in its Mk 2 iteration, which garnered considerable attention for its level of performance at its original price point of around $1200. Soon thereafter came the diminutive USB Renaissance 3R “reclocker,” reviewed in TAS 278. Ideon’s current offerings also includes two other reclocking devices of greater complexity and cost, a streamer, a stand-alone linear power supply, and its flagship Absolute DAC, in development for over three years. In late 2019, Ideon’s product line was taken on by North American distributor Audio Skies of Los Angeles, which carries a number of other top-drawer brands including Larsen loudspeakers, GamuT electronics, and Pear Audio turntables. It seemed an appropriate time for us to have a serious listen to a serious product.

The Absolute is one hefty piece of equipment—bend your knees if you pick it up!—thanks to a 22kg CNC-machined chassis. The enclosure measures 19¼” x 4¼” x 13¾”, the height parameter including four sturdy aluminum pillars. Rounded corners make the box look less severe, and the concentric rectangles cut into its top surface are a nice aesthetic touch. On the front panel are only two functional elements, the 4½” x 2½” LED display and a single large knob that does everything. It turns the unit and off, adjusts volume in the digital domain (if you actually want to—stand by), and changes the input filter or other settings. It’s a little tricky to use at first: You need to remember when to push the knob and when to turn it in order to navigate the menus as intended, but it quickly becomes intuitive. On the rear panel, to the right, is an IEC receptacle (BYO power cord) and an associated rocker-style main-power switch. In the middle are the three digital inputs, one each for coaxial, USB, and AES/EBU connections. Lastly, to their left, are balanced and single-ended analog outputs, one set of each.

Inside the box, students of digital design will find evidence of the innovations and meticulous execution that reflect Vasilis Tounas’ engineering choices. The DAC chipset is ESS Technology’s Sabre ES9038PRO, the most salient feature of which is a dynamic range specification of 140dB. Other manufacturers have utilized this device, but George Ligerakis emphasizes, “If you don’t make sure the whole design of the DAC is appropriate and state-of-the-art, you will never get that impressive result. What we have done, more than most of the others, is to develop many different ultra-low-noise local linear power supplies and a sophisticated analog stage.” The Sabre chip is a 32-bit, 8-channel converter—computations are occurring simultaneously in multiple pathways. Sounding like the computer expert he really is, Ligerakis continues: “We don’t use the classic way of parallelizing the channels of the DAC chip, an area where most manufacturers fail. We do a simple but sophisticated and highly effective parallelization to utilize the high current of these channels. I don’t want to say more, as this is one of the proprietary design elements that we have thought of and implemented!”


DSD decoding is done via DoP rather than natively, something I’m increasingly agnostic about. Most of today’s DACs rely on DoP (DSD over PCM), an interface that formats DSD data as a PCM signal, which then is “unpacked” back to DSD in the DAC.

Though the Absolute allows for both XLR and single-ended analog connections, the signal path within is balanced from start to finish. With his designs, Tounas is clearly obsessed with providing sufficient power, noiselessly, to wherever it’s required. There are independent power supplies serving each stage of the circuit that bypass the main power boards. Ideon describes a “massive multistage power reservoir” comprising 17 low-noise power-supply rails and individual regulation stages. To assure “phase fidelity,” the DAC incorporates three femto, low-jitter/low-phase-noise clock oscillators, each with its own dedicated power line. Additionally, the Absolute’s USB input employs a proprietary three-stage noise-eradication circuit. The output stage is direct coupled, with no capacitors in the signal path.

In the user interface there are just three menu screens that provide all the functionality one needs to operate the Absolute. The main screen allows you to select the digital input, and displays the active source name, upsampling filter identity, audio data frequency, and the gain level, if you’re using the Absolute’s volume control. On the Input Settings screen, the user makes a choice regarding the filter employed. There are seven options that I won’t list here but after listening to each with the same music—an hour or two of my life I’ll never get back—I settled on “slow roll-off linear phase.” Other parameters requiring a decision include settings for an IIR filter (47.44kHz is the default), lock speed (the number of audio samples the machine must see before the digital phase-locked loop, and the Sabre chip’s jitter-reduction algorithm kick in), as well as dithering, jitter elimination, and de-emphasis, for which the options are enabled or not. Finally, on the General Settings screen, one chooses either fixed or variable output for the Absolute, a default volume setting, and how bright you’d like the display to be.

There was no remote control, unlike most of the competition. Why should that be? Read on.

As I usually do with my T+A DAC 8 DSD, I connected the Absolute directly to the power amplifiers, a pair of David Berning Quadrature Z monoblocks. Loudspeakers were either Magico S1 Mk2s (usually deployed here as the surrounds in a multichannel system) or my new references, Magico M2s. Magico’s S-Sub saw some action from time to time, providing support below 40Hz. The digital sources were my long-in-the-tooth Oppo 103 used as a transport, and a MusiCHI SRV-1 server to play files stored on a Synology NAS. Analog cabling was mostly Transparent Ultra, and digital wires included Revelation Audio USB and Apogee Wyde Eye coaxial cables. Ideon encourages experimentation with anti-vibration devices, and I heard improvement with four Ariamateria decoupling feet placed underneath the Absolute’s aluminum pillars.

For my first few weeks with the Absolute, I listened only sporadically as I finished up other projects. There was an obvious “jump factor” going on—plenty of dynamic immediacy—and good detail. My interest grew as I heard the component improve with break-in. (The User Instructions maintain that the Absolute needs “a little over 300 hours to come fully into its own.”) But then the noises started—papery, scratchy noises that sounded like a damaged speaker driver (though the speakers were fine) or a failing capacitor. I checked in with the Ideon folks and their response was consternation. “Even the DAC chip manufacturers recommend that an analog volume control is better than a digital domain control,” replied George Ligerakis. “They recommend that, for critical listening, an analog preamp or analog attenuator should be used in order not to lose the resolution of the bits—meaning, in order not to lose the pure digital playback that is the essence of a good DAC.” This is why there was no remote: Ligerakis tells me that 100% of Absolute owners send output from the DAC to a preamp, which, of course, has its own volume control. Chastened, I started playing the Absolute though one of two preamplifiers on hand with analog volume controls—the Classé Delta PRE, the review of which I’d just finished, and a GamuT D3i on loan from Audio Skies. With both, the extraneous noises disappeared completely and I found myself reveling in the best digital sound I’d ever heard from my system, by a wide margin. As we were about to go to press, Ideon provided a considerably expanded User’s Guide that, among other things, details the benefits of using a quality preamp between the DAC and the power amplifier(s). It mentions the rare possibility that the design of some power amps could result in an impedance mismatch with the Absolute; this was responsible for the spurious sounds I heard when attempting to drive the Berning amplifiers directly with the Absolute.

Perhaps the most striking aspect of the Absolute DAC’s rendering of recordings, the one that’s most redolent of a real performance, is its representation of the dynamic life of music. To be sure, this has plenty to do with the wide dynamic range (and the associated high signal-to-noise ratio) of the Sabre chip and its implementation by Ideon—the Absolute plays loudly with authority and is wonderfully intelligible with the quietest material. A vanishing low noise floor gives intimately recorded music emotional acuity—Christy Moore singing “Shine On You Crazy Diamond” from his 2009 album Listen—and live recordings a captivating sense of occasion—Leonard Cohen’s autumnal Live in Dublin set. An even bigger payoff comes with the recreation of subtle dynamic inflections by vocalists and instrumentalists. You can hear this when Kevyn Lettau modulates the volume of a long-held note in “Everything She (He) Does Is Magic” (Songs of the Police) or in the way the woodwind soloists shape their phrases in the opening Allegretto of Bernard Haitink’s 2010 recording of Shostakovich’s Symphony No. 15. The mid-movement crescendo climax of that same selection crests gracefully, with a sense of ample headroom.

Also apparent with the Absolute was a resolution of musical detail and texture that never seemed unnaturally exaggerated. A receptive listener can make sense of simultaneous musical events in a way that’s typically much easier with flesh-and-blood performers. There’s not just the ability to discern the sound of a tiny triangle over the din of a full orchestra, but a world of subtly variegated tonal color is revealed, if it’s there on the recording. For many, the singing voice of the late Walter Becker, half of Steely Dan, was an unknown, at least until he released a solo album in 1994. Becker often sang background vocal parts on early SD albums, but his contribution was mixed with other singers in a way that obscured its individuality. Occasionally, however, Becker would sing in unison with his partner and Steely Dan frontman Donald Fagen. With the Ideon in the playback chain, he’s audible as his own man. Check out “Any Major Dude” from Pretzel Logic—for years, I thought I was listening to Fagen overdubbed with himself.

Two additional strengths of the Absolute DAC are clarity and speed; again, the kind that’s evident at a live concert, rather than an artifact of an overzealous recording or mastering process. Pianist Marc-André Hamelin is known for his superhuman technique and his 2001 CD Kaleidoscope, recorded for Hyperion in 2001 by Tony Faulkner, programs short, challenging pieces by 17 composer-pianists, including Hamelin himself. Hamelin’s Etude No. 6: Essercizio per pianoforte (Omaggio a Domenico Scarlatti) is a tongue-in-cheek tribute to the Italian baroque composer, and the blisteringly difficult passagework can blur with lesser digital playback. With the Absolute, not only is every note clear, but it’s evident that a machine is not responsible for what you’re hearing—each note is not exactly like the one before or after.

After another month with the Absolute in my system, it was apparent this is a product in the same league as the most ambitious gear from Berkeley, dCS, MSB, T+A, Meitner, and others. I’ve heard these DACs at shows, dealers, and in friends’ systems but, aural memory being what it is, I hankered for a more immediate comparison. I borrowed one of these top-of-the-heap components and devoted some hours to playing the same music through both machines, using the same source components and cabling, matching playback levels within 1dB with an SPL meter. I won’t name which one, as it would be highly irresponsible to declare a “winner” when two such complex devices were being compared for what was still a relatively short period of time. But, given my personal listening biases, I know which DAC I’d choose. The Ideon seemed subjectively louder, with more vital dynamics, and musically relevant details registered more clearly. On the Kaleidoscope selection noted above, there was a little less smearing of that demonically difficult passagework with the Greek DAC. Not night and day, but enough to make a difference. Listening to the competitor, you knew you were hearing an outstanding piano recording. With the Ideon, you could believe you were hearing a piano.

Negatives or compromises, if you will? No MQA, if you happen to be a fan. Even if you’re using an external preamp or attenuator, a remote would still be appreciated for switching sources and to make filter choices from the listening position.

But the fact remains that this is a world-class digital-to-analog converter, and even something of a bargain compared to its most elite competitors. There may be no sunroof or heated front seats, but Ideon’s Absolute DAC is a no-compromise piece of audio gear. In a good way, which is why I’m buying one.

Specs & Pricing

Inputs: USB, AES/EBU, coaxial
Formats supported: 44.1kHz–384kHz/32-bit PCM; DSD via DoP
Outputs: One pair each, balanced or unbalanced, fixed and variable
Dimensions: 19.25″ x 4.25″ x 13.75″
Weight: 57.2 lbs,
Price: $34,900

Parren 6, Neo Phychiko, 11525
Athens, Greece
+30 210 6199887

AUDIO SKIES (North American distributer)
(310) 975-7099
[email protected]

Rogue Audio DragoN Power Amplifier

Rogue Audio needs little introduction in TAS. A perennial overachiever, sonically satisfying and sensibly priced, the company has long been associated with tube electronics. But true to its name, the Rogue team has never been absolutist, blinded by loyalty to the almighty valve. Rather than fleeing from an evolving and tech-driven high end, Rogue has embraced changes for the better. This is where Rogue’s DragoN comes in. It stands atop the Rogue line as its most powerful stereo amp. Indeed, at 300Wpc into 8 ohms and 500Wpc into 4 ohms it has enough output to drive the vast majority of loudspeakers with ease. And at a modest $3995 price it should be affordable for most audiophiles.

Not surprisingly, with this much power on tap in a standard-sized chassis, DragoN is a hybrid tube/Class D design. However, the rogues at Rogue emphasize that it’s not “simply a tube circuit placed in front of a Class D output section.” They describe their proprietary “tubeD” circuit topology as one that integrates the tube section (a pair of 12AU7 tubes) into the amplifier’s output stage. Additionally, three massive linear power supplies built around large, high-performance toroidal transformers power the amplifier circuitry, and top-shelf parts mounted on a heavy (two-ounce) copper circuit board are used exclusively throughout.

Outwardly DragoN pares things down to its chunky essentials. Its Spartan looks are set off by a machined aluminum faceplate. Tipping the scale at just under forty pounds, DragoN is a study in solidity and purpose. A low-power standby mode allows critical amplifier sections to remain continuously powered on (if desired), and a slow-start feature allows the tubes to warm up gradually to eliminate turn-on noise and extend tube life. Rogue considers the DragoN an energy-efficient “green” design, in that it requires zero tube-biasing or regular maintenance. The back panel provides plenty of room for either balanced (XLR) or single ended (RCA) inputs, with heavy-duty gold-plated binding posts and an IEC socket for personalizing the power cord. Every DragoN is tested, burned in, and auditioned prior to shipment. It comes with a three-year limited warranty (six months on tubes).

I asked affable Rogue-In-Chief Mark O’Brien about the hybridization of Rogue’s recent designs. He said, “I’m pretty sure we were the first high-end audio company to come out with a tube/Class D hybrid, and that was back in 2011 (when Class D seemed to finally start sounding pretty good). One of the attractions of Class D amplification is that its high efficiency makes for extremely cool operation, as well as a smaller physical package. What this means is that a well-executed design can work in all kinds of systems—from high-performance audio to high-end home theater. Plus, I really liked the idea of shaping the Class D sound using tubes in a hybrid mode. While we were developing this technology, one of the unique technical achievements we came up with was a way to use a tiny amount of feedback to get the Class D modules to test and, even more importantly, to sound like a super-powerful tube amp. The only downside to our early use of Class D was the negative publicity that was often (and rightfully) attached to first-generation designs.


“We initially chose the Hypex modules because I really like their transparent sound as well as their excellent specs and reliability. Their transparency effectively provides us with a blank canvas on which to create our tube portions of the amp. The OEM modules also offer us the opportunity to add much of our own solid-state thinking to the design—to augment the MOSFET output section of the Hypex. The NCore modules were a no-brainer for inclusion in our new DragoN and the entire amp is designed around them. Beside their great sound, these modules are also microprocessor-controlled, which affords all sorts of features in terms of performance and system protection.”

I commenced my listening sessions using the preamp outputs of the superb Aesthetix Mimas integrated (a 2020 Golden Ear Award recipient) to drive the DragoN. The beneficiary of the amps’ output were ATC SCM20SL compacts, the Sonner Audio Legato Unum, and the PSB Alpha T20 loudspeakers. Sources were the Lumin S1 media player with MQA decoding, dCS Puccini disc player (for SACD), and a newly refurbished SOTA Cosmos Eclipse turntable (with vacuum hold-down and SME V tonearm). Cabling was Wireworld Silver Eclipse. Audience and Shunyata provided the line conditioning The ATCs, it should be noted, are speakers with relatively low sensitivity (84dB). They require significant power in order to snap to attention. The DragoN seemed to fit the bill.

Turning to performance, when I open an evaluation of an amplifier like the DragoN I tend to lean in the opposite direction from where some might assume I’d go with 300 watts to burn. Simply put, rather than cueing up a symphony’s most spectacular moments, I elect to get a handle on the amp’s resolving power with smaller stuff. Reproducing micro-dynamics—the tiny transient cues (right down to a squeaky piano bench or the rustle of a soloist’s clothing) that exist just above a venue’s noise floor—is the key qualifier. This is what I want to focus on at the outset of an evaluation. And this was exactly what I got from the DragoN. In this realm, Rogue’s DragoN manifested a level of near-granular finesse and clarity from back-of-the-hall percussion—capturing the snap and rattle of a drum snare, the flutter of a harp, the plink of a harpsichord, or the clap and jingle of a well-struck tambourine. Transient information—a favorite of mine is the soft tick of classical guitarist Michael Newman’s fingernails upon the strings—was naturalistic. Another prime example is solo piano, which this amp reproduced in a full-throated portrayal that ranged from eerie soundboard harmonics to playful presto notes.

In tonal character the DragoN was predominately neutral, with glimmers of midrange warmth and a well-defined presence range. Violin and viola were particularly well-rendered and distinct, with contrasting attacks and decays. The DragoN’s top end was open if not very airy—a minor deduction. Bass response and retrieval were superb, with very good speed and control. Heavy or ponderous? Not at all. In its transient liveliness the DragoN’s personality was lighter—imparting a feel that was, in a sense, optimistic and upbeat. But the voice of authority lurking was always at the ready—to reproduce an organ’s pedal point or the left hand of a pianist striking the bottom-octave keys of a concert grand. The DragoN’s timbral and textural contrasts between instruments was nothing less than exacting. An example I’ve often pointed to is the complex interplay in the “country-style” chamber music of Appalachian Journey, which, if your system is up to it, mingles varying acoustic densities of fiddle, cello, and bass in a raucous musical stew. The ability of a system to track this recording’s immersive qualities and interwoven images can challenge even the best systems

During the “Liberty Fanfare” from Winds of War And Peace [Wilson Audio] the Rogue resolved the full character of lengthy instrumental and acoustic sustains, including the final decay of the immense bass drum, right down to the tactile ripple of its drumhead. This is the sort of fine-grained, eyebrow-raising information that enriches and authenticates a performance.

When it came time to fully open the taps, the DragoN did indeed perform up to fire-breathing expectations. Taking its full measure was the splendid John Williams At The Movies [Reference Recordings]—in this instance the 24-bit/176kHz version running through the Lumin S1 music player. Of the many great tracks on this outstanding disc, it was the rangy cut from The Cowboys, Williams’ Coplandesque film score, that let the DragoN show off its dynamic and rhythmic drive to best effect. From the youthful, galloping exuberance of the main theme to the brassy majesty of the overture’s middle section, DragoN placed the listener squarely in the saddle. This bouncy liveliness was a constant companion during my evaluation, reminding me that the true goal of a high-power amp is to provide enough headroom to bulls-eye transients and unleash dynamics. A big amp is less about sheer SPLs, which are restricted by the transducers and loudspeaker design, and more about giving those drivers the power they ask for in real time and on an instantaneous basis to preserve resolution and avoid distortion and coloration.

The character of the DragoN also inclined me to reconsider old stereotypes of Class AB tubes and solid-state, and Class D. Not long ago these amplifier segments were often fairly easy to define and distinguish. They had recognizable and predictable characters and colorations. Tubes conveyed a romanticized rose-colored warmth, bloom, and dimensionality, with a gentle rounding of resolution at the frequency extremes, a lack of edginess on top, and a softening of bass timbre. Solid-state weighed in with terrific control and low-end dynamics, great extension at the frequency extremes, with perhaps some edge or grain in the upper octaves. And finally Class D had punch, stump-pulling bass extension and control, a dearth of harmonic bloom, and a limited dimensional perspective. As the hours passed listening to the hybrid DragoN, this sort of typecasting virtually went the way of the horse and buggy.

From the outset it became abundantly clear that imaging and dimensionality were heavily on the minds of the Rogue Audio team. The soaring voices of the Turtle Creek Chorale during the Rutter Requiem conveyed both an immersive and layered quality that drew me ever closer to the performance. The DragoN put on a display of spaciousness that I have rarely experienced in tubes or transistors of this caliber. A sense of air movement in the hall, pressurization within the venue, brought Stravinsky’s ever-colorful Pulcinella ballet excerpts to life. Images were portrayed as they are in life, suspended in a warm atmosphere rather than a cold electronic vacuum. And throughout, there was never a whiff of electronic artifacts smearing the ambience around an image.

In the upper reaches of the high end, there are just a handful of glitter-glam companies that seem to inhale most of the air in the room. Most of us know their names. Granted, they’re dazzling, exquisitely engineered, with musicality to burn. However, to my way of thinking Rogue Audio generally, and the DragoN in particular, represents amplification that in its muscular performance and uncommon value should be equally celebrated. Rogue Audio’s contributions have been vastly underrated in my view, and the DragoN provides even further and unassailable evidence. Not just another high-powered beast, the DragoN is a truly splendid piece of electronics that can proudly grace any system.

Specs & Pricing

Power output: 300Wpc into 8 ohms, 500Wpc into 4 ohms
Inputs: Unbalanced on RCA jacks, balanced on XLR jacks
Tube complement: 2x 12AU7
Output stage: Hypex nCore Class D
Input impedance: 200k ohms
Frequency response: 10Hz–20kHz ±1dB
Dimensions: 18″ x 15″ x 5.5″
Weight: 38 lbs.
Price: $3995

PO Box 1076
Brodheadsville, PA 18322
(570) 992-9901

Charley Crockett: Welcome to Hard Times

With his vital, vintage style, Charley Crockett delivers Welcome to Hard Times, an inspired, timely reminder of how powerful country music can be. After recovering from open-heart surgery last year, the prolific African-American troubadour set out with producer Mark Neil to make a “dark, Gothic record.” His eclectic blend of honky-tonk, blues, folk, and rockabilly evokes a Nashville sound that harkens back to the late 1950s and early 60s. In fact, the album title intentionally name checks a 1967 Western, and its tremolo-laced guitar, saloon piano flourishes, and cinematic sweep would seem right at home in a spaghetti western. From the retro-realism of the title track, a fatalistic country anthem with a gambling motif, to the careening, western swing of “Run Horse Run,” these emotive songs benefit from spare production and echo-burnished sound. With topical touch, Crockett even covers “Blackjack County Chain,” a Willie Nelson hit single from 1967 that was banned from radio because of its lyrics. Charley sings this prison lament as a brutal but haunting dirge, and the chilling story of a black chain gang killing a Georgia sheriff intensely resonates with renewed ramification today.