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IsoTek EVO3 Sigmas AC Power Conditioner

IsoTek EVO3 Sigmas AC Power Conditioner

IsoTek, a company based in Hampshire, England, near Winchester Cathedral, has been in business for over a decade. It has tried to live up to its Gothic neighbor’s imposing reputation by producing what the British like to call “serious kit,” principally by focusing on the foundation of any system—the quality of the power entering your home. As anyone worth his or her audiophile salt knows, there are oodles of companies seeking to purvey products that will allegedly boost the performance of your stereo by conditioning, regenerating, or some other “-ing” the electricity powering it. Some are flapdoodle. Others aren’t.

IsoTek belongs to the latter camp. After Kevin Wolff of VANA Ltd. visited me to pick up the Vienna Acoustics loudspeakers I reviewed for TAS, he also dropped off a box containing an IsoTek EVO3 Sigmas power conditioner. Having used many such devices in the past—ranging from PS Audio to Equitech, not to mention dozens of different power cords—it wasn’t a hard sell to get me to listen to one more. I wasn’t skeptical so much as agnostic, particularly since I’ve gone to some lengths to arrange for the optimal grounding of my stereo.

But once inserted, the IsoTek quickly captured my attention. I had been using a Jadis JA88S MkII integrated amplifier—a wonderful beast, supple and powerful—but there was one nagging issue: It was picking up some hum, and from where I knew not. So I plugged the little French sucker into the IsoTek and was pleasantly surprised to discover that the IsoTek had banished any noise. The tweeters on my Wilson XLFs were silent. The hum, in other words, had gone to whatever netherworld hum occupies.

Score one for the IsoTek. More was to come. I was pleased to note that the overall sound had improved as well. The Jadis sounded more mellifluous and refined. By a wide margin? No. But there were audible improvements across the board. The coveted audio bennies, in other words, were there.

Start with a selection that has been in, as they say, heavy rotation in my system, the Freiburg Baroque Orchestra’s new recording on a Harmonia Mundi of Haydn’s cello concertos. On this CD, Jean-Guihen Queyras’ cello sounded rounder and fuller than I’d remembered it sounding previously. It was also darker, but not in a bad way. This was not a case (as I’ve heard numerous times before) of a power conditioner offering one thing but taking another away. Transients weren’t blunted; rather, they sounded even more precise. The spatial separation between the various instruments also went up another notch.

Similarly, small but significant nuances emerged on Leonard Cohen’s new album Popular Problems. The backing chorus sounded a tad smoother; Cohen’s voice, gruffer. What’s more, the bass line evinced greater solidity, making it easier to distinguish the various musical lines, from the nether regions to the treble. All in all, a very nice perk.

One other effect the Sigmas had (that excellent new equipment often does) was to prompt me to start searching for different recordings to try and see what I’d been missing. This doesn’t amount just to mere detail, but also to the timbres of various instruments. I’m a sucker for hearing a trombone, for example, with its robust blat and punch reproduced as accurately as possible. On the beautifully recorded CD Count Basie Remembered, the IsoTek not only helped better convey the toe-tapping propulsive character of the cut “Broadway,” but also allowed me to visualize trombonist Dan Barrett sliding his way through a number of intervals during his solo. By lowering the noise floor—something of a Holy Grail for any audio system—the IsoTek allowed guitar and bass to come through with a truly byssine sheen.

Then there was the almighty Arturo Sandoval’s album Trumpet Evolution. This is one of those great curiosities, a tribute CD on which Sandoval, with uncanny accuracy, plays in the style of everyone ranging from King Oliver to Louis Armstrong, from Timofei Dokshizer to Maurice André. Each one is every-so-slightly distorted but the overall verisimilitude is so prodigious that it’s a treat to play. Once again the more stygian black spaces that the IsoTek produced allowed the distinctiveness of Sandoval’s trumpet playing to resound with even greater fidelity than I had hitherto experienced.

How does the IsoTek accomplish this feat? Normally a review lists the important technical aspects towards the top, but in this case I had such a good time with the IsoTek that I wanted to cut straight to the chase.

Without belaboring the point, the unit appears to be of sterling quality. It features six outlets with two dedicated for high-power equipment, such as amplifiers or subwoofers, that are said to deliver up to 3680 watts of continuous power. Each outlet is scrupulously divorced from the other so that there is no possibility of cross-contamination. Indeed, IsoTek says it eliminates both common mode and differential mode noise, a claim I am inclined to support after hearing its effect on the Jadis. The IsoTek also has a front panel that, with the push of a couple different buttons, allows you to see the voltage or total harmonic distortion coming from your wall outlet in what amounts to real time. Finally, IsoTek touts Kirchhoff’s law of equal paths of resistance, which the company says means that its products have fully symmetrical signal paths.

This is by no means the most elaborate mains conditioner (to use the British term) that IsoTek constructs. It sells a variety of even more sophisticated units, not to mention power cords and audiophile-grade connectors. Judging by the performance of the Sigmas, IsoTek is producing state-of-the-art power devices. If you’re looking for a conditioner to tackle the vexing issue of electricity quality and to improve the sound of your stereo, then I can emphatically recommend the IsoTek EVO3 Sigmas.


Outputs: Six: two high current, four medium current (16A, 5A)
Power handling (230V, high current): 3680W continuous
Total transient power handling (high current): 15,000W
Dimensions: 444 x 90 x 305mm
Weight: 10 kg
Price: $4500 (includes EVO3 Premier C19 power cable)

VANA Ltd. (U.S. Distributor)
728 Third Street, Unit C
Mukilteo, WA 98275
(425) 610-4532

By Jacob Heilbrunn

The trumpet has influenced my approach to high-end audio. Like not a few audiophiles, I want it all—coherence, definition, transparency, dynamics, and fine detail.

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