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Supra Ply 3.4 S speakers cable

The Sonic Shield

[Italian version]

Product: speakers cable Supra Ply 3.4 S
Manufacturer: Supra/Jenving - Sweden
Approx. price: 20 $ per meter (may vary from Country to Country)

[Supra Ply 3.4 S]

Supra from Sweden became famous for introducing the first HiFi-oriented loudspeakers cables back in 1976, that is more than 20 years ago.
Since then the research in cable technology has given us a large amount of fancy theories, designs and...cables.
Tommy Jenving has always based the development of his cables on serious electronic research, studying all the parameters that can influence the performance of a conductor. While the first Supra cables (now still available as Classic series) were based on the use of pure OFC copper and on low resistance/capacitance designs, now the continuous research has led new concepts, all successfully applied into the Ply 3.4 S speakers cable.
Let me just briefly summarize the main ideas on which the standard Ply 3.4 is based.
The Ply 3.4 makes use of 192 pure tin plated OFC copper strands in a low inductance design. The advantages of low inductance and tin plating can be summarized as follows: low inductance gives a better transient performance while the tin plating minimises the (in)famous skin-effect by acting as a semi-Litz conductor and minimises also the current jumps over oxidized surfaces of individual wires in the conductor, so to say, such a configuration works with the same advantages of solid-core cables.
The tin plating is considered better than the silver plating because copper and tin "melt" together without creating a diodic barrier such as between copper and silver.
Moreover the tin plating protects the OFC copper from oxidation.
The rectangular section of the Ply 3.4 makes it easy to match with the majority of speakers connectors (bananas, forks etc.).
Some tech spec for the standard Ply 3.4: cross-section 3.4 mm2, 7 Ohms per km (kilometer!) resistance and a mere 0.2 µH per meter inductance.
On the Supra catalogue are available some screen shots from an oscilloscope showing the square-wave reproduction of a Ply compared with the one of a standard wide-spaced cable.

Now, take a standard Ply 3.4, add a shield and you get the Ply 3.4 S (S for Screened or Shielded) we are reviewing in this article.
The screen stops the radiation of interference fields from the loudspeaker cable and eliminates its influence on the sensitive input circuits of the amplifier. Normally, loudspeaker cables radiate stronger alternating fields than those of ordinary mains cables.
This is the concept on which our TNT Star DIY cheap cable was based: low inductance and shielding from interferences.
The screen is meant to be connected at one end only, to a ground screw or to the chassis of the amplifier, whereas the shield should be left disconnected at the other end (the loudspeakers end).
I've tested the Ply 3.4 S into various configurations, both in mono- and bi-wiring.

The Sonic...Shield

Firstly, let me point out that the effect of the screen is remarkable. It is sufficient to disconnect it to learn how much relevant is for sonic performance (see below).
The Ply 3.4 S is very neutral and well balanced and hence it is a GIANT step forward with respect to the Classic series loudspeakers cables from Supra. The frequency "equilibrium" of the Ply 3.4 S makes it more balanced than the Supra EFF-I interconnects I tested some months ago here on TNT-Audio.
The bass range is well extended and harmonically rich with a vibrant "oomph", powerful and controlled till the deeper end. The best quality of the bass of the Ply 3.4 S is its linearity, that is the flat frequency response, no peaks and no weak spots...
The mids are neutral and the sound is never "in the face", always controlled and undistorted: voices and acoustic string instruments flow through this cable effortlessly, virtually, dare I say it, realistic :-)
The Ply 3.4 S does have well extended highs, of the sweet kind, like those of a good tube amp. Hey, "sweet" doesn't stand for "rounded", eh! OK, it is not the high range of a good silver cable but it is still very detailed and refined.
Finally the Supra is excellently coherent through the whole frequency spectrum.

Dynamics and 3D soundstage

The dynamic performance of this cable is very good below 100 Hz where the Ply sounds powerful and excellently controlled. Around 100 Hz it lacks some punch and impact but it is still very articulated and "damped". The Ply is a lively cable, fast and accurate, precise both on attacks and decays.
Given the price, the dynamic performance is simply outstanding.

3D imaging is excellent, especially with the shield connected to the ground of the amplifier: try to disconnect it and you'll see the height of the soundstage collapsing...
I've tested this effect with a recording with a very good 3D image, especially with respect to the height of the scene: Cantate Domino by Proprius, church pipe organ and choir.
With the shield disconnected the scene collapses and it seems the organ is just "spread" over the floor, instead of being well focused behind the rear wall and above the ceiling.

Some advice

Just a few. The Ply 3.4 S can easily find its place into a large number of HiFi chains, thanks to its tonal balance and neutrality.
As noted above, the shield should always be connected to amplifier's end.
A little problem may happen if the ground screw (or any other metallic part of the amp) is far from the speakers output posts. In this case you can add a short piece of cable from the ground screw till the shield.
Quite surprisingly the Ply 3.4 S has needed a longer than usual break-in time. After the first day of extensive listening it sounded pretty bad. So I've noticed it needs AT LEAST 10 hours of continuos listening before giving the max of its performance.
Trust me, the difference is outstanding.


The Ply 3.4 S is a champion of flexibility (hence the name? Ply!) but, just to make it "perfect", I'd suggest to offer it also in a complete 3 + 3 m package, with the shield already connected to the negative pole or even with a small conductor to be used to connect the shield to the ground of the amp. This way it will be even easier to use and mistakes of novices will be avoided...I've learned, thanks to this TNT-Audio experience, that no matter how you try to write things CLEARLY there's always someone who can't understand or read the instructions correctly. So give him a fool-proof package, so he has to just plug and play!
A short note about the outer ice-blue sleeve: it is very cool and living-room friendly but it attracks dirt like a vacuum cleaner! Maybe a less cool but "cleaner" grey sleeve would have worked better...
From a purely sonic point of view, considering the price it is almost impossible to complain about anything...just some extra punch around 100 Hz would be welcomed, though.


The Supra Ply 3.4 S is, given the price, simply outstanding.
Neutral and balanced it possesses a very deep bass range, good transient response and a very good 3D imaging. It is not expensive (I'd say cheap...), it is not as "fat" as some ridiculously oversized competitor, it is user and living-room friendly and it is easy to match with a large number of amps and loudspeakers.
Despite its low price it can successfully compete with very expensive and "esoteric" competitors. A winner.

A warm thank you to Tommy Jenving of Supra for having sent us the first meters of the brand new Ply 3.4 S for this World Premiere listening test.

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