Supra Excalibur speaker cable

Supra Sword Excalibur Speaker Cable REVIEW

December 8, 2020
8 mins read
Supra Sword Excalibur Speaker Cable REVIEW


Supra Sword Excalibur Speaker Cable REVIEW

RICHARD VAREY has three words for the new Supra Sword Excalibur speaker cable: clarity, transients, wow! He bought the cables.


Supra Sword Excalibur review
Supra Excalibur speaker cable

Once again I’ve been getting wired with Mark Polglase’s Supra cables. Or I should say, with one very special new product, the Sword Excalibur speaker cable. A couple of years ago, I Supra-charged my audio system by installing all-Supra cables, and this is an update on the occasion of two new product upgrades coming to my attention.

I looked at this audition two ways. As a Yorkshireman, I’m not impressed by bluster and hyperbolic claims, but I do appreciate great musical experiences. I knew from my previous experience with Supra cables that there’s no fairy dust in this product range: this is about sound engineering, the pleasure of music listening experience, and fair prices.

“There’s no fairy dust in this product range”

This speaker cable stands out from the crowd. It looks different. The chivalrous romanticism of the name Sword Excalibur drew me to it. But what did the name have to do with a product that looks like a shiny blue snake? Then, huh? Synchronicity is a curious thing.

Pioneering psychologist Carl Jung proposed that events are “meaningful coincidences” if they occur with no causal relationship yet seem to be meaningfully related. On the very same day as the name of this new product sent me in search of the story of ancient monarchical powers, a distant friend independently posted a comment on Facebook mentioning that name! Now I was even more curious.


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In some ancient tales, Excalibur (also sometimes known as Caliburn or Calibumus) was the most powerful and magical sword drawn by King Arthur from the Magic Stone or anvil (because he was the rightful king). In another folklore telling of the appointment of the rightful leader of the Britains, Arthur receives Excalibur from a mysterious Lady of the Lake as a replacement for the first Excalibur which broke! Multiple versions of this story abound, and it’s all a bit confusing, and that makes the tale of this particular modern-day manifestation of Excalibur all the more especially worthy of telling.

Supra Sword Excalibur review
The Supra Excalibur cable where it belongs – on a speaker binding

The designer faced the same concerns as the mysterious devisers of Arthur Pendragon’s test of greatness – performance requirements, selection of materials and components, and construction/configuration.

What’s crucially significant about the Sword Excalibur cable is that designer and hi-fi enthusiast Johnny Svärd, a former telecommunications engineer, understands information transmission in copper conductors. Also crucial is that manufacturer Jenving has the advanced engineering experience and specialist machinery to produce in-house.

The Excalibur speaker cable is a specially configured use of Jenving’s Sword cable. The cable is constructed with bifilar (fine thread) wound Litz conductors, each comprising 24 individually insulated wires. The bifilar winding is built with 12 of these wires helically wound in one direction and 12 wound in the opposite direction. This divides the magnetic field into opposing directions resulting in self-cancellation.

Because Sword’s conductors comprise a number of insulated wires, dynamic skin effect is cancelled. Therefore, Sword behaves as a non-inductive and phase-stable cable. It was developed to be sonically ‘invisible’, free from time delay and phase distortion, and thus especially revealing of the musical interpretation of the source and amplifier that it carries to the loudspeakers, and not adding and subtracting anything.


Litz wire is a special type of multistrand wire designed to reduce the skin effect and proximity effect losses in conductors. It consists of many thin wire strands, individually insulated and twisted together in a specific and precise configuration.

This equalises the proportion of the overall length over which each strand is at the outside of the conductor, with the effect of distributing the current equally among the wire strands, reducing the resistance. Impedance extends the concept of resistance to alternating current (AC) circuits, with both magnitude and phase, unlike resistance, which has only magnitude.

When a circuit is driven with direct current (DC), there is no distinction between impedance and resistance; the latter can be thought of as impedance with zero phase angle.

The very high quality of the materials and assembly is very obvious. There are two enamelled Oxygen-free Copper conductors composed of 12 + 12 strands, each 0.4 mm diameter, per conductor. Insulation is PE, mounted in a protective PVC jacket. There’s an integral CNC-milled cable splitter and a third 30cm XL-Annorum earth/screen wire to be connected to the negative speaker terminal (or an earth point on the amplifier cabinet).

Connectors are Rhodium-plated. This is an ultra-rare, silvery-white, hard, corrosion-resistant, and chemically inert transition metal. A member of the noble Platinum group, it’s a valuable precious metal. Not only does it ensure pristine and durable conduction, it also imbues the Excalibur with exotic quality. Termination crimping is airtight, and connectors are threaded and so easily interchangeable. Jenving also produces a Sword speaker cable, and Sword interconnects with the Sword cable.

“It was developed to be sonically ‘invisible’, free from time delay and phase distortion”

All of this engineering results in a speaker cable that performs differently. Engineer Johnny Svärd used an HP 4192A impedance analyzer to measure and monitor the opposition to alternating current in Sword cables compared with several other branded and generic cables. Impedance refers to how the chemical and physical properties interact with voltages and currents, i.e. how well the cable passes current. Inductance, capacitance, and resistance were measured for every frequency up to 200kHz.

I’ve seen the numbers which show that there is no phase deviation in the Sword cable, but severe phase shift errors in each of the others tested. These time errors are very audible. The effects differ markedly by frequency and between cables. In an AC ‘transmission line’, there are ‘oppositional’ losses and the conductance varies with frequency. Hence tonal character is introduced as the effect is not linear with frequency and some peaks of emphasis (reinforcement) and troughs of suppression (cancellation) may be evident.

The Sword cable configuration renders it linear in response to current passing through it, and effectively inert, and so current passes unchanged and unimpeded. Conductance is very high and linear with little loss. The Sword cable is “electrically transparent”, behaving as a signal medium and not a modifier. The configuration cancels dynamic skin effect which affects the tonality of the sound, and reduces the resistance that affects transient response.

Supra Sword Excalibur review
The Supra Excalibur cable where it belongs – on Richard’s speaker

What then, audibly, do you get when the cable inductance is effectively zero across the entire audio spectrum? It’s the auditory equivalent of seeing a favourite snow-topped mountain, golden beach, or river valley vista with no haze in the air to obscure and distort the clarity and vividness of the sky.

I’ve considered the rationale for this design, drawing on my physics and electrical and electronics engineering education, and have concluded that the performance promises are highly credible, backed-up with sound engineering. And then I heard it all in practice. After daily listening over several weeks, I think it’s down to three words ….. clarity, transients, wow!

“There’s more direct connection with the sound – up close with the players and very revealing.”

I was initially surprised that the enhancement in the presentation is so obvious. I was already a fan of the Supra XL Annorum that I’ve been using for some time. The Sword Excalibur is even better at enabling a very open and dynamic presence in the music recordings reproduced. The sound is free and easy – more unconstrained, open, and immediate.

More of the recording image is getting through to the speakers – evidently there’s much less obstruction from counter-forces and confusions. The cable carries the current without getting in the way, so there’s more direct connection with the sound – up close with the players and very revealing. I’m more aware of noticed differences among recordings, and have to accept that some recordings are just disappointing when openly revealed in this way. I’m getting a clearer view of the image generated by the source – great music recorded carefully is conveyed pleasurably, as the emotional impact is revealed without hindrance.

In ancient folklore, Bedivere returned the sword Excalibur to the Lady of the Lake. At least three Welsh lakes – Llydaw, Dinas and Ogwen in Snowdonia National Park – are claimed to contain Arthur’s magical sword. According to one legend, when the sword was thrown towards the lake, a woman’s arm clothed in silk reached up from the depths of the water, catching the blade before pulling it under.

The Supra MD06DC mains block

This Sword isn’t the compromise kind of system component that needs to be upgraded. And what would be a better performance-value option anyway? It didn’t take me long to decide that I wasn’t going to part ways with the Sword Excalibur cables. They’ve earned pride of place in my musical image rendering apparatus.

And it seems that Johnny Svärd is the modern-day hero – he’s the patent holder for this Bifilar Wound Litz cable configuration. I had previously wondered about the reason for this name for a product that more resembles a pearly Python than a long-blade weapon. It’s actually really simple. The name Svärd translates to English as Sword.

The name Excalibur conjures thoughts of chivalric courage, courtesy, and loyalty, dignity, and generosity. That’s a brand identity I can buy into, and the Sword Excalibur cables are certainly big, greathearted, lofty, and noble performers, and I’m delighted that I now have them in my audio system.

As well as a highly satisfying product experience, and a brief dip back into past times, there’s some subtle Swedish humour in this story. On the Jenving website, there’s an apology for the low price of this high performance. While it may confuse superficial comparisons with other speaker cables, that’s a design feature that I fully appreciate. Well, I am a (thrifty) Yorkshireman who loves music.

“On the Jenving website, there’s an apology for the low price of this high performance”

I am also mightily impressed with the impact this cable has on the performance of my audio system. It is for me a legend, as we say in New Zealand, but from my knowledge of physics and electronic engineering, I see that it’s no myth. I hear it clearly (literally).

While investigating this advancement of Jenving’s Sword cable, I found out that the name Excalibur ultimately derives from Caledfwlch (Welsh), Kaledvoulc’h (Breton), and Calesvol (Middle Cornish), which is a compound of caled (“hard”) and bwlch (“breach, cleft”). Caladfwlch seems to be derived from the name of another ancient sword, Caladbolg, meaning “hard lightning”. That seems so appropriate for this outstanding electrical conductor!

Earlier, I mentioned that two upgrades are now available from Jenving. The other is their Supra LoRad power outlet block. I’ve been using a six-way version with non-intrusive filtering and surge protection along with a discrete DC-blocker. The new unit conveniently incorporates both devices into a single block with eight outlets, and has beefed-up surge-protection capacitors. The aluminium chassis shields electrical and magnetic radiation (“Low Radiation”).

All models in this patented range incorporate Supra NIF (Non-Intrusive Filtering), a moderate transient filter which doesn’t affect the transient capabilities of attached equipment. The noted Ben Duncan Research is responsible for this technology, and they’ve ensured both protection from malfunction due to Radio Frequency Interference (RFI), and benign audiophile properties. With this power supply intervention and the Sword Excalibur in place, my latest system Spring cleaning effort is even more Supra than last time.

  • The Excalibur cables are $2295 inc GST for a 2 metre pair, and $400 for each additional metre pair.
  • The original Sword loudspeaker cables are $1195 for a 2 mtr pair and $300 each additional metre pair.
  • The 6-way (1 unfiltered high current outlet) MD06DC Mains Block is $1195.00.
  • The 8-way (2 unfiltered high current outlets) MD08DC Mains Block is $1295.00 inc GST


Equipment used for this audition:

JRiver MC27 and Fidelizer Pro 7.8

Black Ice Audio Fusion Tube DAC Transport

ONKYO NS-6170 Network Audio Player

Black Ice Audio F360 Tube Preamplifier

Black Ice Audio F22 Tube Integrated Amplifier

Audio Pro Avanti 100DC Floorstanding Loudspeakers




Whilse auditioning the Excalibur, I learned that Polglase Enterprises has recently been appointed as the Jenving/Supra Cables distributor for Australia, in addition to New Zealand.


For five decades, Richard has assembled music systems that enrich his music listening experience. He writes about the electro-mechanics and social psychology of this technology-facilitated art we call high-fidelity music reproduction, and about his experiences with interesting hi-fi ideas, equipment, and the people who make it.

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