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IsoTek EVO3 Aquarius AC Power Conditioner

I’m not proud to admit that I arrived a little late to the party for AC power conditioning. I was not a skeptic per se, but at the time I was so intent on assembling a reference system that line conditioning had dropped off my radar. This is not uncommon. We put AC power concerns on the back burner, kind of like room acoustics. Let’s face it: As long as you’re plugged in and, uh, current on your electric bill, everything should be okay, right?

Not necessarily. Line conditioners perform a couple of critical housekeeping functions. First, they prevent cross-contamination from the other components within your audio system, including digital components. They remove EMI and antennae noise (RFI) that originates within your home from computers, Wi-Fi, appliances, and dimmers. No less important and as unlikely as it sounds, they isolate the system from the upstream EMI/RFI that gets dragged in from everything else outside your home that’s connected to the grid. Hard to believe that some of the grunge in your line is caused by a 1600-watt hair dryer in a next-door neighbor’s bathroom, but that’s what “sharing the grid” means. 

More recently I read with interest colleague Jacob Heilbrunn’s review of the IsoTek EVO3 Sigma power conditioner in Issue 254. His remarks caught my eye, especially in the context of his state-of-the-art system and the bespoke environment of his discretely grounded, electrically and acoustically optimized listening room. His system, a Wilson Audio WAMM/Ypsilon/Continuum/dCS Vivaldi 2.0 rig is pretty much the definition of resolution and transparency in the here and now. Yet, Jacob’s conclusions showed that even under such elite conditions the IsoTek was still capable of furthering system isolation and reducing the noise floor. I figured if IsoTek could do that for such a system, what might one of its lower-priced versions accomplish in a more typical setup and listening environment? 

Enter the IsoTek EVO3 Aquarius, a more affordable version in the EVO3 series from this British-based company. The rack-width steel-and-aluminum chassis houses six outlets—two high-current outlets, rated at 16A, suitable for power amplifiers, active loudspeakers, or subwoofers, and four medium-current outlets. Aquarius benefits from much of the innovation and technology of the uptown Nova and Sigma conditioners in two unique areas. Primary is KERP (Kirchoff’s Equal Resistance Path), which “ensures equal resistance and equal power delivery to all outlets.” There’s no daisy-chaining thus no outlet gets power before the next. This means that noise created by your system’s electronics will not migrate to the next output socket. Equally important is that each outlet is assigned its own dedicated filter network, which ensures optimal isolation between outlets. Additionally, the medium-current outlets auto-sense the requirements of the load based upon power draw. IsoTek asserts that its technology removes both differential-mode cross-contamination (appliance noise) and common-mode (RFI) noise, with a reduction of 60dB. Aquarius also features IsoTek’s unique sequential protection system boasting 67,500A of instantaneous protection from surges or spikes. Internal wiring is solid-core, silver-plated, OFC copper with a virtual air dielectric technology plus an outer dielectric of FEP/Teflon.

Aquarius is supplied with an IsoTek EVO3 Premier power cable. Cords are an important part of the system equation in that they also minimize noise and don’t limit current delivery. All the contact points from the AC wall outlets and power cords into the electronics are of equal importance, which makes it imperative that power cords and even premium duplex outlets, such as the Furutech GTX (Issue 291), are considered. In my system these elements magnified the dimensional and immersive effects of the IsoTek. Returning to stock power cords and a standard wall outlet diminished these properties.


For this evaluation my system consisted of the Pass Labs preamp driving an ATC SCM50A active, three-way floorstander. Sources were a Clearaudio Satisfy Black analog rig and an Oppo Sonica streaming DAC equipped with the top-flight ES9038PRO 32-bit HyperStream DAC chip. Power cords were Audience Au24SX with Tara Labs Air Evolution interconnects (reviewed in the last issue).

Each time I embark on an audio review I remind myself to expect the unexpected. And thus far pretty much every piece of gear I’ve evaluated has surprised me in some way—subtle and elusive at times, and others as obvious as a punch in the nose. The Aquarius was not quite a sock in the schnoz, but in terms of three-dimensional presentation, clean transients, plus its depiction of micro-dynamic and low-level information, it packed some real moves.

A prime example that I constantly turn to is the Keith Johnson-engineered Reference Recording of Rutter’s Requiem. The complex array of voices in the Women’s Chorus of Dallas and Turtle Creek Chorale is a challenge for any system, but the IsoTek enabled a more cohesive, unified presentation across the full stage, while also imparting a greater and more specific sense of the individuality and height cues of the voices. Further, during the toccata from Stravinsky’s Pulcinella, woodwinds, oboe, and bassoon suddenly snapped to attention, right down to the tick of fingering changes. Even on the most commercial pop or rock recordings, images achieved a stability and individual clarity that I hadn’t expected from reverb-and-compressor-laden multitrack. 

All genres of music benefitted from the addition of the IsoTek Aquarius, but truth be told, the fullest realization of its potential occurred while listening to purist, uncompressed acoustic music with naturalistic tonal, ambient, and reverb characteristics. A favorite example of mine is Laurel Massé’s a cappella rendition of the Quaker hymn “How Can I Keep from Singing?” [Feather & Bone], recorded in the superb acoustics of the Troy Savings Bank Music Hall in New York. Via the Aquarius, the spaces between images seemed to open up and the entire cavernous hall seemed to exhale in relief, as if, after holding its breath, it could finally inhale again. 

I think of AC line noise as a subtle but pernicious kind of audio compression—the more noise and grunge, the greater the loss in low-level micro-dynamic energy and transparency, like the interplay of a chamber group or the harmonization of a pair of backup singers or simply the resting sound of a concert venue during musical pauses. Details such as these tend to get swallowed up in a noisy system. In suppressing line noise, IsoTek unlocks low-level transparency in the same way that removing layers of old wax from a fine wood surface allows more of the inherent depth and beauty of the wood-grain patterns to shine forth. When I listen, I want to be able to follow the harpist gliding along during Vaughan Williams’ The Wasps Overture. Part of the joy of this hobby is to be able to hear each harp string even as the orchestra wells up.

I’m aware that power conditioners may not be at the top of every audiophile’s to-do list. But eventually, as one’s vision of a high-end system comes together, affording a conditioner a comprehensive test drive is a logical and, I think, necessary step. And the good ones like IsoTek offer both protection and performance in various configurations at prices that won’t blow a fuse. But more specifically I was impressed by and grew ever more addicted.

Specs & Pricing

Outlets: Six total (two high-current; four medium-current)
Dimensions: 17.5″ x 3.5″ x 12″
Weight: 20 lbs.
Price: $1995

(312) 738-5025

By Neil Gader


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