One of the biggest complaints I’ve heard from audiophiles is that “power conditioners don’t work.” However, that sentence should be amended to say that low-quality power conditioners don’t work, and they usually do more damage than good. Most often, they rob your system of dynamics, resolution, and fine detail. If you are new to the power conditioning journey, it’s easy to mistake lower background noise for improved fidelity, but after a while, you find yourself unplugging it all, going back to the dynamics you had before, and taking a bath on Audiogon.
To make things even more complicated and frustrating, there are different types of noise attacking your hifi system, so a single solution won’t address them all. That’s part of the big price tag on the Concerto Mk.II – It’s actually three power conditioners on one chassis, and you need all three. If you have a turntable or multiple turntables, you actually need a fourth, but we’ll address that later.
First things first
Before you spend any of your hard-earned money on a power conditioner, I suggest addressing the low-hanging fruit in your system’s power system first. Not only will this allow the effects of said power conditioner to reveal themselves in a more meaningful way, but it will also give your system an even more lifelike result. Think of your audio system as a race car. Everywhere you can grab 2-5% more performance, all adds up to bigger gains in the end.
First, check the ground from your electrical panel to Earth. You’ll need to hire a licensed electrician for this, but again, a couple of hours of an electrician’s time is noise (pun intended) compared to the cost of the Concerto and your total system cost. Always eliminate variables.
Next, while the electrician is there, have them make sure all your outlets are connected correctly, i.e., in phase. This is often overlooked, especially in homes less than 20 years old. Most construction crews aren’t anticipating you putting a mega sound system in the living room, and if a couple of outlets are out of phase, or even improperly grounded, it’s not going to affect how your toaster browns your morning bagel. However, if you’ve ever had that annoying little 60 Hz hum that won’t quite go away, this might be your problem. Also, make sure all your outlets’ connections are tight.
Finally, while the panel is open and you have all the circuit breakers in view, have their connections checked for maximum snugness – and the ground wires going to the bus bar inside the panel.
Once this is completed, you should notice a lower noise floor, and you’re ready to bring out the major artillery.
Set up part one
If you have a turntable, four major types of noise are invading your system. Turntable motors are notoriously dirty, and both Clarus and I highly suggest removing them electrically from the rest of the system. I use a massive battery/inverter to power my turntable motors, effectively eliminating them from my listening room’s AC. Clarus suggests one of their Duet power conditioners or another form of isolation for your turntable motors. Depending on the table you use, this will be a minor or major source of system-related noise and hash that ends up sounding almost like the glare from early digital products. Remember, every couple of percent.
The Concerto Mk. II has a full 20-amp capacity, which works well in my room, because there are four major 20-amp circuits feeding my reference system. A pair of individual 20-amp circuits feeds the Pass Labs XS300 monoblock amplifiers, which draw about 1000 watts each. As the Concerto has a maximum capacity of 2400 watts when connected to a 20-amp line (1850 watts with a 15-amp line), I’ll speculate that a second or third one might offer some benefit here. For this review, the XS 300s were not connected to the Concerto Mk. II. It was used to excellent effect with a number of smaller power amplifiers and integrateds with considerably lower current requirements.
More noise
Turntable motor noise out of the way – or if you are a digital-only music lover, there are still three things to address, and the Concerto Mk.II takes care of all of them.
Around back are four duplex outlets. Two are marked digital, one analog, and one high-current. High current is for your power or integrated amplifier, and this bank uses Clarus’ new FluxCore-HC common-mode filters to deliver maximum uninterrupted current flow and a low outlet impedance to make it happen. Common-mode filtering is aimed at EMI and RFI and is usually present between the line and neutral connectors. (rear photo courtesy of Clarus)
The digital outlets rely more heavily on filtering differential mode noise, which is usually generated by digital circuits, switching mode power supplies, and those annoying wall wart power supplies. So, plug your DAC, streamer, and network switch in here. I also connected our ROON Nucleus to the digital outlets, along with the Mojo Mystere DAC in the main systems.
The analog outlets focus more on filtering line-current noise. This is perfect for preamplifiers and phono stages. If you’ve ever had a tube linestage or phono pre where the power transformers ran a bit warm, some of this is line-current noise at work, stressing the system. I noticed a marked difference in the surface warmth of the power transformer in both a vintage Dynaco PAS 3 preamplifier and the conrad-johnson Classic Phono SE when plugged into the analog outputs.
You can read more techie bits here at the Clarus website:
https://www.claruscable.com/power-conditioners-and-blocks/clarus-concerto-mkii/
Another nice touch with the Concerto Mk.II is it provides under- and over-voltage protection, shutting things down in the event of AC line voltage rising above 135 VAC or falling below 90 VAC. Undervoltage can be just as damaging to your gear as overvoltage. An audible alarm lets you know what’s happening, and it can be disabled. An internal MOV with 960 joules of surge suppression capacity is the final line of defense. Finally, a cable support is included to reduce mechanical strain on the outlet connections and provide maximum mechanical stability – a nice touch.
Though it’s a few more bucks, after you’ve gone through all this work, invest in a heavy-duty power cord to connect the Concerto to the wall. Clarus was kind enough to send one of their Crimson – high current power cords to go with, and it is the icing on the cake, especially if you are plugging a lot of gear into the conditioner. A wimpy power cord in this critical link will not deliver all the performance you paid for.
Sound improvements
Extensive listening with an incredibly wide range of components leads to the same result every time. The Clarus conditioner improves everything, while doing no harm anywhere. That’s what you write the big check for. FYI, I have addressed all of the issues mentioned at the beginning of this article in my studio’s power.
When listening to music with wide dynamic range and extended quiet passages, it’s easy to hear just how much quieter things are. Classical music enthusiasts will be thrilled, whether listening to music on digital or analog formats. This additional quiet makes everything sound louder. That’s what loudness is all about. You can either increase amplifier output power or lower the noise floor. Your system will sound bigger, more dynamic, detailed and more musically engaging when you plug into the Concerto Mk.II.
When listening to acoustic music, and anything with a lot of drums, piano, or percussion, more texture is present, without truncating the leading and trailing transients that define instruments. Even when listening to electronic and techno tracks, there is more sparkle, ambiance, and more clearly defined spatial cues. You don’t have to listen to string quartets to appreciate the Concerto Mk. II! Additionally, acoustic instruments gain greater clarity and tonal accuracy. Analog and digital recordings both have considerably less electronic haze and cloudiness.
A higher jump factor is present everywhere, and the added dynamics present in all three of my systems is instantly noticeable, even more so when the Concerto mk.II is removed from the systems. Where other conditioners have failed moderately to miserably, the Concerto mk.II is a solid upgrade.
It’s also worth mentioning that most DAC/streamers you plug into the Clarus will sound less etched and less electronic in the final presentation. Even if you have a great DAC, going back and forth between Concerto in and Concerto out will probably reveal an improvement.
Final listening
All praise of the Concerto Mk. II nonwithstanding, it’s even better and more effective on a high sensitivity, low-power setup. If you have a set of horns or other really efficient speakers, you know that they are flypaper to noise anywhere in your system.
The 103dB sensitivity of the Klipschorns lays everything bare, and this was where I noticed an even greater lack of background anomalies. Even putting my ear right up to the tweeter horns reveal dead silence. At the risk of hyperbole, I think the Concerto Mk.II is a must have addition to a low power/SET/Horn system.
Is it worth it?
To me, it is, and it is more than enough to purchase the review sample. If you have a highly resolving system and are looking for the next step in revealing more music, I suggest taking the Clarus Concerto Mk.II for a test drive if you have a Clarus dealer nearby. This is not a component you will have to agonize over to hear the improvements it makes. You’ll notice it right away.
In the context of a $50k-$200k+ system, the improvement it delivers is well worth the price. In addition to giving this a Product of the Year award, I’m buying the review sample. – Jeff Dorgay
$12,000
claruscable.com
Clarus CCP-HC Power Cable (20A)
$1,900 – $4,840 (length dependent – not included)
Peripherals
Analog Sources SME 20 turntable, Bergmann Thor turntable, Technics SL-1210G turntable, Thorens TD-124DD turntable, Otari 5050 reel dec
Phono Preamplifiers conrad-johnson Classic PhonoSE, Hagerman Trumpet, Soul Note A-2, PassLabs XP-17
Digital Sources dCS Vivaldi ONE and Vivaldi Clock
Amplifiers Pass Labs XS300 Monos, Pass Labs First Watt SIT-5 monoblocks, ampsandsound Bryce Monoblocks, PrimaLuna EVO400 monoblocks
Speakers Klipschorn AK7 w/six pack array of REL HT-1510 subwoofers, Clarisys Auditorium Plus Speakers w/six pack array of REL Carbon Special Black Label subwoofers, Pylon Audio Jade 30
