PlusSound Quad Copper EXO cable.
Looks like PlusSound (PS) is rolling into their 11th year with another new release, this time aligned with CanJam SGP weekend. 2022 was a big year for them, celebrating 10-year anniversary, introducing the rest of their ‘+’ series cables, releasing TWS-C wireless adapter, and then finishing it up with a big unexpected surprise, Allegro flagship IEMs. This new cable release, Quad Copper, is an upgraded version of their popular Tri-copper cable from 5 years ago. And as the name suggests, they went from three (tri) wires, Pure Copper, Silve-plated Copper (SPC), and Gold-plated Copper (GPC) to “quad” by adding another wire ingredient, Palladium-plated Copper (PPC) wire borrowed from their Palladium Plated Hybrid (PPH) flagship cable.
But this wasn’t just the addition of another wire twisted in a bundle, they actually modified the existing Type 6 Litz design by adding extra strands per bundle, extra wires into every bundle which made the cable more supple. The insulation, dampening cores, and the usual cryo treatment remained the same, but the geometry has changed and it is noticeable when you feel Tri-copper and Quad Copper side by side, with latter one being softer and more flexible. And it also makes a big difference when handling Copper+ which has a lot stiffer design. Furthermore, to commemorate this 11th year anniversary limited edition, the leather storage pouch and the cable organizer leather band are now brown instead of black.
I spent a week with this cable, pairing it up with different iems, including PS own Allegro. Also, tested and compared it with a few other PS cables. As my usual disclaimer when I talk about cables, I do hear the sound difference, but it’s not as drastic as measurable EQ adjustment, more like a noticeable finetuning effect. If you don’t like the baseline sound signature of your IEMs, no cable alone is going to change that.
With a number of different IEMs, the original Tri-copper had a typical “copper” sound characteristics with a warmer tonality including more weight in bass, fuller body mids, and more sparkle in treble. Quad Copper is a not as warm, but rather a “smooth” cable. It does accentuate the sub-bass rumble and the mid-bass articulation in a number of iems I tried, and it gives vocals more body, but mids are affected differently with this Quad. I have to assume this is a direct effect of additional PPC wire where mids/vocals are more transparent and have more clarity. At the same time, I hear Quad to take the edge off the treble. I’m still on the fence if the treble is smoother by itself or the more clarity in mids creates a less extreme contrast with treble to make it sound smoother.
The overall change in tonality with the addition of new PPC wire improves the clarity of the sound, without making it brighter, and makes the treble a little smoother which works great with IEMs where you want to keep sibilance under control. The improvement (more clarity) in mids also opens up the sound, expands the soundstage and slightly changes the imaging. For example, vocals spread wider and at the same time feel like being placed closer to the listener.
In a direct comparison using Allegro and LPGT as a source I hear:
Tri-copper to Quad Copper – Quad has a noticeably wider soundstage, spreading wider with the sound wrapping around your head, expanding the soundstage on a level of their PPH8 flagship cable. Also, vocals are placed further out with Tri while Quad brings them closer. Plus, as I already mentioned, I hear the improvement in clarity and retrieval of details in vocals. I don’t want to say that Tri is warmer, but Quad offers more clarity in mids. Also, Tri-copper treble is a little brighter. Furthermore, Quad Copper wires are softer than Tri-copper.
Copper+ to Quad Copper – in this comparison a soundstage width is very similar. The position of vocals is a bit more out of your head (Copper+), on par with Tri-copper, while Quad brings vocals a little closer to the listener. The main difference here is in tonality with Copper+ being a noticeably warmer cable, having smoother mids with extra sparkle in treble, while Quad has more transparent cleaner mids and vocals, and more controlled treble. In this comparison, Quad treble still offers plenty of clarity with a moderate sparkle, but it is less intense, smoother. And as expected, Quad is a lot softer than Copper+
IMHO, the sound and the color pair up synergy between Allegro and Quad Copper cable is a perfect match. As I mentioned in my Allegro review, Tri-copper was one of my favorite pair ups with those IEMs. Quad Copper scales it up with more clarity in mids/vocals, smoother and more natural treble, and wider soundstage perception. Plus, for additional $200, going from Tri-Copper to Quad Copper is a reasonable price upgrade.