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QED Supremus loudspeaker cable

QED Supremus loudspeaker cable

Back in the 1990s, QED was the UK’s ubiquitous cable brand. The company’s iconic and affordable 42 strand and 79 strand loudspeaker cables are still available and still sell at a prodigious rate. The proceeds from those cables allowed the company to finance investigations (see, to try to equate what can be measured with what we hear in the loudspeaker cable realm. Lessons learned from this report were applied to subsequent QED cable designs, right up to the company’s new flagship Supremus loudspeaker cable.

Having that measurement-to-ear basis has meant QED has long eschewed the more ‘unobtanium’ end of the cable metallurgy and construction spectrum. The Supremus design uses 16 silver-plated, 99.999% pure oxygen-free solid-core copper conductors, creating a 10AWG wire, with a cross-sectional area of 6.2mm2. This represents the largest cross-section of any QED cable to date, and in the process gives Supremus a very low claimed loop resistance of 0.005Ω/m. The design of the cable itself uses QED’s AirCore technology, which uses a foamed polyethylene inner core (around which the conductors are wrapped) with an foamed polyethylene dielectric outer core and further small hollow tubes of foamed polyethylene within the cable jacket to both even out the design and to keep inductance to a low stated 0.49µH/m and capacitance to a suggested 48pF/m. It is also designed to alter the magnetic field across the length of the cable to make high-frequencies travel along the centre of the cable rather than the outer part, thereby limiting any potential skin effect issues.

QED uses a thin layer of enamel on each conductor on the Supremus design. The whole 8mm diameter design is then jacketed (to make a 17mm diameter cable), cryogenically treated, and then terminated in the factory using the company’s own cold-weld AirLoc plugs. A further bonus unique to the Supremus design is these connectors are rhodium plated. This caused a slight delay in the review, because although 4mm plugs were ready right out of the starting gates, spade lugs (required for my Wilson Duette II speakers) were delayed in manufacture. Once they were ready, the cable was good to go, and arrived in a box about the size of a small LP carry case.


A word about the packaging is in order. It’s notionally a trivial thing (you buy loudspeaker cables for their sound and their performance in a system, not the box they arrive in), but an increasingly important aspect of the whole cable purchase. QED is normally used to making products that work on display stands in stores, but Supremus is more of a gift to you, or your system, and it shows in the packaging. The stiff, dark grey has the QED logo on a magnetic clasp, the box folds open and your cable is neatly coiled, and hiding behind a signed certificate of ownership. There will be some who dismiss this out of hand as ‘nonsense you pay for’, but anyone who has ever owned a watch that didn’t come free with six gallons of petrol knows the importance of that cachet attached to the packaging. Even if the only time you use it is when you bring the cable home, and it spends the next few years collecting dust, or as a place where you ‘file’ odds and ends, chances are the box will stay with the cable.

The technical aspects of the cable potentially point to two facets of performance, which hold very true in the auditioning. The low loop resistance that is a result of that large cross section of cable results in better control over a loudspeaker by any given amplifier. I am wont to create ‘mullet’ systems with the Duettes, using far more humble amplification than might normally be expected to partner a pair of speakers of their calibre, and that included a Musical Fidelity Encore 225 and even a Hegel H80. The latter can get a little ‘tense’ when driving Duettes at a lick, but Supremus just stressed the amplifier slightly less than usual and made it drive louder, longer.

While we are pinning sounds to the performance, the unstressed high-frequencies of the design also shine through. There was no glare, additional brightness or ‘spitchiness’, but neither was this a dull, rolled-off cable. It was very much in the Goldilocks spot. 

But there’s more than that to Supremus. It has that sort of coherence and balance that typifies the best of the best. And, although it’s expensive (especially by QED standards), this is audio cable we’re talking about: 3m of the best of the best could bankroll a space program. Of course it means it’s inherently ‘honest’ sounding, with no sins of commission, but it has that ‘disappearing’ quality that suggests it has few sins of omission, too. With fine soundstaging, excellent detail, powerful (and once again effortless) dynamics, and a fine sense of vocal articulation, you would need to spend a lot more to improve on Supremus.

The biggest downside is availability. QED has a handful of Supremus dealers around the UK, but it’s proving so popular that it’s taking its time to filter though QED’s international network. Those few dealers in the UK keep on demonstrating it, and people keep on buying it, before it gets a chance to leave these shores. 

My choices of cable systems fall into three distinct camps: the inherently neutral and melodic (AudioQuest, Cardas); the incredibly detailed and harmonically structured (Crystal, Nordost), and the musically and rhythmically accurate (Chord Company, Clearer Audio). In an ideal world, there would be the One Cable, the one that did all these things well in equal measure. QED’s Supremus gets tantalisingly close to being that One Cable To Rule Them All, without any significant downsides, too. Highly Recommended! 


QED Supremus Speaker Cable

Conductors: 2 × 16 solid core silver-plated 99.999% oxygen free copper conductors

Insulation: Unique enamel with low loss surround foamed polyethylene dielectric insulation

Cross-Sectional Area: 6.16mm²

Wire Gauge: 10 AWG

Jacket Outside Diameter: 17mm

Loop Resistance: 0.005 Ω/m

Capacitance: 48 pF/m

Inductance: 0.49 µH/m

Dissipation Factor: 0.009

Price: £1,160/3m pair (as tested)

Manufactured by: QED/Armour Home Electronics


Tel: +44(0)1279 501111


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