Synergistic Research PowerCell SX

REVIEW
Ed Selley
May 26, 2026

Building any piece of audio equipment with transparent panels that showcase the internal workings reflects a certain confidence from the manufacturer. On the other hand, doing this with a mains conditioner—a device often regarded as merely a box of air with some sockets on the back—feels particularly bold. Synergistic Research has considerable experience in this area. The Synergistic Research PowerCell SX certainly isn’t just a box of air. Therefore, the confidence is likely warranted.

PowerCell SX is, in fact, a cross-pollination of the existing PowerCell 12 and the higher-spec Galileo SX PowerCell. It utilises Active EM Cells, which are intended to project an electromagnetic field that filters and redirects contaminants. This feature is found in most of the company’s mains treatment devices. The power supply for these devices is sourced directly from the Galileo SX. It also incorporates the Ground Plane to reduce the noise floor further.

Five Tubes

These cells appear as five carbon fibre tubes laid flat at the rear of the chassis. They are 25% denser than the cells used in the standard PowerCell 12. Additionally, they are connected by a sixth flat EM Cell, visible as a black rectangle with two silver stripes. In the standard PowerCell 12, this is tuned to a harmonic of the Earth’s Schumann Resonance frequency of 7.83Hz. In the Synergistic Research PowerCell SX, this is extended to all six cells to enhance the soundstage and reduce listening fatigue.

Other parts lifted from the Galileo include the power supply for biasing all six of its internal Active EM Cells. It also includes the ability to externally ground the PowerCell SX. This is an interesting and flexible feature. Specifically, it can be connected to either an unused wall socket. Alternatively, it can be connected to one of Synergistic Research’s dedicated powered Active Ground Blocks.

Dedicated power

Also noteworthy is the mains input, which is via the dedicated SRX power cable that terminates in a locking type connection. This cable is a veritable firehose of silver conductors within an Air Dielectric shield. To its credit, it is more flexible than it appears. Thus, this simplifies installation.

Another nod to practicality is that the PowerCell supports 12 IEC sockets arranged in two rows, one inverted over the other. Given the nature of the UK mains socket, there are no perfect solutions for fitting 12 sockets into one chassis. For example, I have found that the clearance between the lower sockets and the shelf on which the Powercell SX sits is a bit tight for some of the more rigid cables I have here. Still, it’s a commendably neat piece of packaging. Judged by the standards of mains treatment devices, it’s also quite an attractive one. The viewing panels are internally lit. There is an option to change the colour of the illumination to better match your equipment. The front one features a large ammeter. The overall build quality is perfectly good. And installation was hassle-free as well.

Protect and survive

I have been using mains conditioners in my system for many years now. However, these have generally been selected for their protective properties. They keep my house safe from equipment, and vice versa, rather than for the presence of quantum tunnelling in their design. Nevertheless, the PowerCell X proceeded to do a number of positive things right from the outset. It has proved completely silent in use. Additionally, connecting a medley of items, including wall-wart type PSUs and switch-mode devices, did nothing to alter this.

Furthermore, focusing on a McIntosh MSA5500 as the primary connected device (and one already extensively ‘sighted’ on a more prosaic IsoTek Sigmas conditioner) reveals that the PowerCell X is capable of delivering some interesting benefits. Listening to the newly released Electric War by Little Barrie and Malcolm Catto [Easy Eye Sound] keeps the very deliberately rough and ready production intact. However, it slightly prises it open. This reveals what a great piece of music this is. Catto’s ‘not quite jazz, not quite rock, not quite breakbeat’ percussion on Spektator absolutely crackles with energy. Accordingly, the effect is hugely enjoyable.

Soundstage promise

There are benefits, as promised, to the soundstage as well. Running with a pair of Sonus faber Sonetto V G2 floorstanders, the McIntosh is already usefully expansive. However, the PowerCell SX managed to bring a greater sense of order and depth to the live Acoustic Blues Club recording by My Baby [Self Released]. This further helps you truly feel like you are part of a live performance. Importantly, this is achieved without unsettling the fundamental realism of what you hear.

Testing a Vertere MG-1 MkII turntable and Musical Fidelity M8 Vinyl phono stage with the vinyl copy of this album, while also connected to the PowerCell SX, revealed similar benefits in three-dimensionality and imaging. Interestingly, if only one of the two devices was returned to the resident PowerGrip YG-3 conditioner, there was a small but noticeable reduction in this effect.

Repeatable

Regardless of my position on certain unique aspects of the Synergistic Research design language, the effects appear to be repeatable. Similarly, a Chord Electronics Hugo M Scaler and TT2—two devices I’ve found to be consistently immune to mains treatment—maintained their impressive performance in this regard. Crucially, however—unlike some devices I’ve tested with these units—the Synergistic Research did not negatively impact their performance.

This shouldn’t really dent your perception of what is an unusual and rather effective bit of kit. The Synergistic Research PowerCell SX isn’t cheap. There are other mains treatment devices at this relatively rarefied price point that can feel more solid. However, the actual performance on offer here is extremely good. What’s more, there are enough sockets available to accommodate all but the most determinedly enormous systems. There’s a bit of visual flair while it does it as well. Viewing panels in mains conditioners might not be commonplace. But Synergistic Research has enough reason to show off what they’re doing. As a result, most owners will be pleased to have them.