The Sigma NR v2 power cord sits at the top of Shunyata Research’s new Reference Series of noise-reducing (NR) power cords, which also includes the new Alpha and Delta NRv2 models. These new offerings were developed using the same designs and technologies found in the top-of-the-line Shunyata Omega QR power cord.
Product Information and Design
The new Noise-Reduction Version 2 (designated here as “NR v2”) are distinguished from the original “v1” series of NR power cords introduced in April, 2017, by a new design and new features. Notably, the NR v2 series introduces a conductor geometry and construction designated “VTX-Ag.” This design comprises an inner conductor of pure silver with a concentric outer conductor of high-purity OFE copper. The materials and geometry are said to combine the transient speed and definition of silver with the warmth, power, and body of copper.
The Sigma NR v2 power cord also utilizes a refinement of Shunyata’s patented noise-reduction (NR) technology, which provides ~12dB of “in-line” noise reduction. This multi-element, wide-bandwidth noise-reduction technology was developed by Shunyata Research’s medical division, Clear Image Scientific, to improve the performance of medical imaging systems in cardiology and neurosurgery. The noise-reduction filter is built into the component-end plug.
The NR v2’s build has also been refined and improved to provide superior audio quality over first-generation NR power cords. For instance, each power cord is treated with Shunyata’s innovative and proprietary Kinetic Phase Inversion Process (KPIP) for a minimum of four days. The KPIP process significantly reduces burn-in time, as well as improving sonics. Most notably, I’ve found that KPIP-treated power cords provide a relaxed and lifelike presentation from the get-go, eliminating the hassles and uneven performance often associated with burning-in new power cords.
On the outside, the Sigma NR v2 is an all-new design, with a black TechFlex jacket terminated with plugs of genuine black carbon-fiber and metallic trim rings. The overall appearance is very attractive, crisp, and modern, and exudes quality. The new design also utilizes Shunyata’s proprietary CopperCONN connectors, which maximize current delivery. The CopperCONN plugs are flash-plated with nickel to ensure contact integrity and provide durability. Not only are the genuine carbon-fiber plugs very sexy looking, they are also functional, as they attenuate and damp micro-vibrations that can impact maximal sound quality. Even though the Sigma NR v2 is a 6AWG cord, it is very flexible and supple, which makes routing and connecting it easy.
Setup and Configuration
For this review, I used Sigma NR v2s to power my Conrad-Johnson LP-70S amplifier, CT-5 preamp, and Schiit Gungnir Multibit DAC. All components were powered by connecting the Sigma NR v2s to my Shunyata Denali 6000/S v2 power distributor, which was connected to the AC wall receptacle with the new Shunyata Sigma XC power cord. The Sigma XC is the same-specification power cord as the NR v2, absent the noise-reduction filter, and specifically designed for delivering maximal current to power distributors. The Denali v2 is a key player when used in conjunction with the Sigma NR v2, as I’ll explain. My digital front-end networking components: Mac Mini music server, UpTone Audio EtherREGEN, and SOtM SMS-200 UltaNeo network bridge were powered using Shunyata Venom V14D digital power cords, specifically designed for this class of device.
Prior to installing the Sigma NR v2 power cords, I was using a mix of Shunyata Venom NR-V10, NR-V12, and Delta NR v1 power cords. After installing the Sigma NR v2 in the system and letting them settle for a day or so, I gave them a listen. It was a veritable revelation.
Let me provide some context: From the first Shunyata Diamondback and Venom 3 power cords I purchased in 2009 and 2010, respectively, my experiences with Shunyata power cords have been positive. Over the years, I’ve come to the conclusion that the power cords and power distributor are the most important parts in a high-end audio system. You don’t build a superb house on a weak foundation; you build it on the best foundation, for sound (no pun intended) engineering reasons. The power distribution of a high-end audio system is no different.
Successive generations of Shunyata’s power cords have resulted in an increased reduction in noise, hash, and grunge, and a concomitant increase in resolution, transparency, bass articulation, and definition. I’ve heard some really good power cords over the years, but the new Sigma NR v2 breaks fresh ground in audio reproduction, and most notably, does so in different ways than I’ve experienced to date.
Listening to the Sigma NR v2 cord it quickly became apparent that standard audio-review terminology didn’t apply. Rather, I came to the conclusion that using the Sigma NR v2 in conjunction with the Denali V2 power distributor required a new vocabulary as well as a new perspective, because the intrinsic quality of the musical presentation was different in a fundamental way. The most accurate way to convey this change is to adopt the language used to describe fine musical instruments, e.g. how a Stradivarius sounds compared to a Guarnerius violin, or how a Bösendorfer sounds compared to a Steinway grand.
This power cord brings an accuracy of timbre and harmony, a musical veracity, that I’ve simply not experienced before. Yes, it’s got all the audiophile virtues I’ve described in my previous experiences with Shunyata power cables. But those attributes really don’t speak to what the Sigma NR v2 is about.
While it sounds amazing on all types of music, the qualities of the Sigma NR v2, particularly when used in conjunction with the Denali V2 power distributor, are most fully evident on classical symphonic pieces. The power cords and the distributor work in harmony to provide a class of resolution, timbral definition, transparency, vocal and instrumental accuracy, hall spaciousness and ambience that I have not experienced before. All of this is heard against a background so quiet that the experience is like sitting with the musicians, rather than sitting with the audience. On Joaquín Rodrigo’s Fantasia para un gentilhombre with Pepe Romero and the Academy of St Martin in the Fields [Philips 438-016-2], Romero’s guitar is so fully and clearly articulated that you can hear his clear ringing tone, the spruce-and-cedar character of his guitar, and the nuances of his virtuosic technique perfectly articulated, even against the backdrop, complexity, and power of the full orchestra going flat-out behind him during very dynamic passages. Moreover, there is so much precision you can “zero-in” on every single instrument in the orchestra in the beautiful acoustics of Watford Town Hall in the UK. Normally, during these passages like these, the subtle, intricate musical details of a classical guitar can get lost against the background of an entire symphony playing en masse. With the Sigma NR v2, you can hear and pinpoint each individual musician or instrumental voice within the full orchestra.
In studio recordings, the gestalt is one of actually being in the studio during recording rather than listening to playback of the recording session. On recordings such as Kenny Burrell’s “Saturday Night Blues” on the seminal hard-bop album Midnight Blue, or Melody Gardot’s “Your Heart is Black as Night” from My One and Only Thrill, I can hear the secondary reflections and, most incredibly, the decay of these secondary reflections splay off the opposite wall in the recording studio. “Tibet” on I Ching’s Of the Marsh and Moon [Chesky Records] is a sophisticated mix of Chinese instruments with complex tonal structures. With lesser power cords, this tapestry of sounds can easily become somewhat congested, but with the Sigma NRv2 every instrument is reproduced with extremely finely resolved detail, timbral texture, and harmonic accuracy.
A friend recently asked me, because of the silver in the VTX-Ag conductor, whether its signature was on the analytical side of the equation or the “warmer and richer” side that some legacy Shunyata power cords, e.g. the “CX Series,” were known for. It occurred to me that I had never considered this question because the Sigma NR is so neutral. And by this I do not mean what “neutral” has come to mean to some audiophiles, which is slightly on the lean, spare, or cool side, rather than the warmer, more romantic side. I mean truly neutral: The Sigma NR v2 imposes virtually no coloration or shading of its own on the music.
Maximizing the Performance of Denali and QR/BB
The traditional experience of listening to live or reproduced music is one of the listener sitting back from the musicians performing in a hall or concert stage. Not so with the Sigma NR v2 and Denali v2. Rather, the soundstage and imaging is so three-dimensional and holographic it’s as if you being surrounded and enveloped within the music. Moreover, each musician and instrument is focused, palpable, and fully fleshed out. Upon reflection, it occurred to me that the Sigma NR v2 was letting me fully hear the impact and functionality of the QR/BB device in the Denali 6000/S v2 power distributor. A good analogy would be putting a larger throttle body in the fuel injector of a high-performance motor. Providing more instantaneous current (what Shunyata refers to as Dynamic Transient Current Delivery or DTCD) enables the full performances of the motor, or in this case, the QR/BB device in the Denali v2. This device, used in the Shunyata Tyhpon QR and Denali power distributors, fundamentally changes the presentation in a way that the audiophile terminology we’ve used for the last 40 years no longer adequately describes. Put quite simply, one has to experience it to get it.
I could go on, but the most important way I can sum up what the Sigma NRv2 power cord does (particularly when it is used with a Denali v2) is to say that it sounds as if you are in the room with the musicians as they create the music in the moment.
With the Sigma NR v2, my traditional perspectives on what a stereo system can reproduce has shifted away from a language that describes gear to a language and sensibility that describes music. Remarkable, truly remarkable.
Specs & Pricing
Conductors: 06 VTX-Ag
Noise reduction: >12dB @ 1MHz
IEC connector: C19 20A, C15 15A
Lengths: 1.25m or 1.75m (standard length is 1.75m)
Digital sources: Schiit Gungnir Gen 5 USB Multibit DAC, SOtM SMS-200 UltraNeo network bridge, Mac Mini Roon Core Server, Sonore OpticalModule fiber media converter, UpTone Audio EtherREGEN Ethernet switch, UpTone Audio LPS-1.2 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: Conrad-Johnson CT-5
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 NR V2 power cable (preamplifier, amplifier, and DAC) V14D Digital (digital networking components, Delta and Venom interconnects, Sigma Ethernet & Alpha USB digital cables, Delta V2 VTX-Ag speaker cables
A/C Power: Shunyata Research Denali 6000/S V2 and SR-Z1 wall outlet
By Stephen Scharf
I’ve worked as a molecular biologist for my entire professional career. As one of the inventors of Polymerase Chain Reaction (PCR), I worked in human molecular genetics and developing molecular-diagnostic and DNA forensic testsMore articles from this editor
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