So, you’ve assembled this great high-end system—components, speakers, cabling, isolation devices, various tweaks, and so on—and you’re experiencing what you believe is the highest fidelity your system is capable of. But have you considered power conditioning? The subject is not nearly as controversial as it once was. Most major audio magazines, this publication included, have extolled the virtues of cleaning up the power that runs from the wall to your stereo.


The problem in evaluating their effects is that power conditioners are designed to remove noise, not add to or enhance the musical signal. Many current components already incorporate various levels of power conditioning, some quite sophisticated. This is an area where system-to-system interactions may greatly vary, even more than with other gear. Stated more simply, some types of equipment are more profoundly affected by power fluctuations or impurities than others. With that caveat out of the way, let’s look at a very interesting design by Clarus, and a handsome one at that. Unpacking the Concerto power conditioner ($3600, all prices USD) revealed a solid, elegant, full-sized black chassis with a neat, uncluttered front panel.


The eight-outlet Concerto (19″W × 3.5″H × 12.75″D, 19 pounds) is the flagship in Clarus’s power conditioner lineup. Unlike any conditioner I have used, it has separate banks of outlets for different applications: there are four outlets devoted to digital equipment, one pair each labeled Digital 1 and Digital 2. These filters are designed to maximize the attenuation of noise when feeding power to DACs, CD players, and other sensitive digital components. There are two outlets—aptly named Analog—for components like preamps and phono stages, which, according to Clarus, allow the “music to bloom” without dynamic restriction. There are also two outlets labeled High Current; each incorporates a massive 30A Clarus-Core (C-Core) filter, designed to allow high-current equipment—like power amplifiers and powered subwoofers—to likewise be run through the Concerto without dynamic restriction.


The conventional wisdom used to be that power amps should be plugged directly into the wall for best dynamic-range performance. Clarus wants you to plug your amp into the Clarus—this is the primary purpose of their C-Core technology. The company’s C-Core technology is employed in both the High Current and Analog banks, but not the four digital outlets. For digital, Clarus uses a proprietary array of multi-level filtering that is said to work well for reducing noise to minuscule levels. Clarus’s C-Core technology is designed to nearly eliminate magnetostriction, the process by which materials change shape when magnetized. This is also said to reduce unwanted noise.

Clarus also uses special materials on the chassis to reduce noise, describing their effects as follows:

The high internal damping of ISODAMP Vinyl and ISOLOSS vibration control products reduces mechanically or acoustically induced vibrations and dissipates shock and impact energy at an increased rate. This allows for the reduction or elimination of noise in industrial, electronic, structural, and ergonomic applications caused by resonance and vibration.

Clarus employs a voltage regulation alarm in case voltage drops below 90VAC or spikes above 135VAC. If a voltage drop or spike occurs, the unit will automatically shut down until a safe operating voltage is again achieved. There is also surge protection, which employs Thermal-protective Metal Oxide Varistors (TMOVs), to ensure that the unit shuts down if the surge protection circuit is tripped.


Other useful features include polarity and ground LEDs, which indicate if the power cord and the outlet the unit is connected to are wired with the correct phase and properly grounded. Another well-thought-out design feature is a cable support bar that keeps heavy cables from slipping out of the receptacles. I have a lot of power cords, some of which are python-like and very heavy. The Concerto kept these unwieldy cables tighter to the unit, and the receptacles gripped the plugs firmly. Last year, I wrote an article for SoundStage! Global on the Furutech NCF Booster-Brace, which provides a snugger fit between power cords and receptacles. This borders on the ultra-esoteric and requires a bit of faith in nanoscience, but the concept that a better fit ensures better contact and transmission doesn’t really strain credulity. At the very least, you get a tighter connection, and the platform supporting the weight of the plug ensures that plugs won’t sag or become loose or even disconnected. This is a great feature, and I wish more manufacturers would consider ergonomic issues like these when designing gear.

Setup, use, and initial listening

I inserted the Concerto into my downstairs reference system via the manufacturer-supplied Clarus Crimson High Current power cable ($1920 for a 1m cord). I plugged the McIntosh MC2301 monoblocks directly into the Clarus via the High Current receptacles. The other components were divided according to digital or analog applications, and there were more than enough plugs to meet my system’s needs.


For several years, I’ve faithfully used the McIntosh MPC1500 power conditioner ($5000), and I’ve also run amplifiers through this unit, although the McIntosh doesn’t have dedicated outlets specifically for power amplifiers. The Mac monos are rated at 300Wpc into 8 ohms, but my Tannoy Westminster Royal GRs ($60,000 per pair) have a sensitivity rating of 99dB, so I didn’t have an opportunity to test the 15A limit of the MPC1500. The Concerto also has a 15A capacity and can deliver 1800W maximum, which suggests that it should be able to accommodate all but the most robust power amps.

Another benefit of power conditioners is that they increase the number of easily accessible outlets. The Concerto’s excellent cable support system made this even easier because the power cords were all arranged in a neat, orderly fashion and snugly fit the receptacles.


While I was running all my components through the Concerto, the sound of my system remained as refined as I’m accustomed to hearing it, with all of the air, details, and dynamics intact. I did find that the leading edges of transients were slightly sharper through the Clarus. Many weeks of listening confirmed this observation. Things like percussive attacks and finger snaps had a slightly more convincing decay. All of the other hallmarks of my reference system were preserved as I knew them. I could not reliably detect any other improvements or diminished performance in terms of the overall sound when compared to my McIntosh unit.

In my mountain home

I then took the Clarus to my mountain vacation home and inserted it into the very capable system I have there—essentially a scaled-down version of my home reference rig (see equipment listing below). At the time of my listening tests, I had recently assembled this system and had yet to incorporate any power conditioning, so this provided an excellent opportunity to assess the effects the Concerto would have on an “uncleaned” system. The improvements the Concerto brought to this system were not subtle. It was like feeding a high-performance car engine with 93-octane gasoline instead of 89; better fuel produces a better result. Every aspect of the sound was more refined and more vivid. I was always better able to perceive fine details and subtleties.


Listening to John McLaughlin and Paco de Lucía play off one another in “Frevo Rasgado,” from the iconic Friday Night in San Francisco (SACD, Philips SONSA19637N) with Al Di Meola, I found that the strings had more bite, and the finger slides were more easily discernible than without the Clarus in the system. Even through some passionate exchanges, there was no blurring of strings or muddiness—the Clarus aided in keeping individual elements well delineated. There is a lot of nylon being plucked on this track, and the resonances remained crisp and audible. Even the audience’s clapping was cleaner with the Clarus.

Listening to “The Duke” by The L.A. Network (Dave Brubeck Redux, 24-bit/192kHz FLAC, Pro Studio Masters 2XHDRE 1162), I found the bass lines were some of the most natural and textured I have experienced. Devoid of haze or noticeable artifacts, the lower frequencies just bloomed, as did the piano tones which emerged from a more distinctly recessed space on the stage than they had sans Clarus. This excellent recording was taken to another level with the Concerto feeding my system, mainly the result of a less congested soundstage.


Whatever filtration the unit performed was always beneficial to the overall sound. It was similar to upgrading a level or two within a manufacturer’s component or cable line. There were no dramatic “Wow, the improvement is like night and day” moments, but whatever haze, hash, grunge, or grit was being stripped away rendered the overall musical presentation more “there” and more believable. Voices sounded fleshier and better isolated within the soundstage. Cymbals were crisper and splashes were just splashier. I could go on about the way the frequency extremes sounded slightly expanded or how backgrounds were blacker, but the point I want to make should now be obvious: the sound was better.

The Concerto performed as advertised without even a hiccup.


The improvement power conditioning can have on a system highly depends on the factors I detailed earlier, and your mileage may vary. That said, I am a firm believer in power conditioning, and the Clarus Concerto is one of the most interesting and thoughtful designs I have encountered.


Retailing for $3600, the Concerto is not inexpensive, but it offers a lot of technology and useful features, including the ability to run high-powered amplifiers and further optimization for digital and analog components. All of that considered, along with the protection it offers against power surges or instability, the Concerto’s asking price is an insurance policy that a good system will be able to live up to its full performance and be protected against damage from most power fluctuations or even catastrophic failures.

For those with great audio systems, power filtration is necessary to get the most from them. The Clarus Concerto is a top-notch performer and very competitively priced given its impressive design and sophisticated engineering. I recommend it highly!

. . . Jeff Sirody

Associated Equipment

Downstairs reference system:

  • Speakers: Tannoy Westminster Royal GR.
  • Amplifiers: McIntosh Laboratory MC2301 (monoblocks).
  • Preamplifier: McIntosh Laboratory C1100.
  • Digital source: McIntosh Laboratory D1100 DAC and MCT450 transport linked via MCT cable.
  • Analog source: Clearaudio: Innovation Wood turntable, Universal tonearm, Stradivari V2 cartridge.
  • Speaker cables: Wireworld Platinum Eclipse 6.
  • Interconnects: Wireworld Platinum Eclipse 6 and 7.
  • Power cords: Electraglide Ultra Khan, Purist Audio Design Dominus and Aqueous Aureus.

Mountain home system:

  • Speakers: Tannoy Kensington SE.
  • Integrated amplifier: Luxman L-590AX.
  • Digital source: Audio Research Corporation CD-7 CD player.
  • Speaker cables: AudioQuest Gibraltar.
  • Interconnects: Purist Audio Design Venustas.
  • Power cords: Purist Audio Design Venustas.

Clarus Concerto Power Conditioner
Price: $3600.
Warranty: Three years, parts and labor.

Clarus Cable
Gordon J. Gow Technologies, Inc.
6448 Pinecastle Boulevard, Suite 101
Orlando, FL 32809
Phone: (888) 554-2494
Fax: (800) 553-1366