Hardware Reviews

Curious Evolved USB


Australia is not the first place that comes to mind when hi-fi comes up but there is plenty of interest in the subject down under and a handful of manufacturers plus the occasional superstar designer, Mark Döhmann creator of the Continuum Caliburn turntable is from that part of the globe. There are also more accessible operations and Curious Cables is a recent addition to those ranks, the man behind the brand is Rob Woodland who licensed Keith Eichmann’s technology and manufactured the Bullet Plug RCA connector, he subsequently became interested in computer audio and developed the first Curious USB which was released in 2015. Encouraged by its success Rob developed the Evolved USB, which has the same topology and uses annealed silver in an air dielectric, where no insulation actually touches the wire.

Annealing is effectively the opposite of cryogenic treatment, it’s a high rather than a low temperature process that aims to achieve the same alignment of crystals within metals. You don’t often hear about annealing in audio but certain well regarded tube amp output transformers use annealed copper and it’s a well established process in certain fields.

Another of this cable’s distinguishing features is the absence of shielding on the signal cable, this is because Rob found that it “shut down dynamics”, but the ground and 5V lines are shielded as these two connections have a greater potential to transmit noise. The 5V line is the thin wire you see on the outside, where it’s as far from the signal cable as possible (also the case with my preferred USB cable from CAD). The ground cable has been “beefed up” in the Curious Evolved because Rob found that it is crucial to the end result, he goes so far as to call it a “ground system”. This is undoubtedly why you get so much difference between USB cables, they seem far more open to refinement than coaxial SPDIF cables for instance where there is little to be changed apart from materials.


The main cable is in a braided sleeve and construction is professional but not fancy with branded heat shrink covering the connections to USB A and B plugs at either end. These plugs are apparently modified to give greater conductivity compared to the standard Curious USB.

You probably won’t have read this far if you don’t believe a digital cable can make a difference but it’s worth saying that they do, it only takes a quick A/B demonstration comparing almost any two to hear it. Whether you want to hear it is another question but if you feel that digital streaming doesn’t sound as good as CD for instance consider trying a different USB cable. They can make a flat hard sounding system sound open and natural or speedy and exciting, take your pick. Cables, especially digital cables are tricky things to make a living out of. You spend time and money in research and don’t want to give away your trade secrets when it comes to market. Max Townshend (another Aussie) rues the day he told the world about cryogenic treatment because it meant that everyone and their dog could copy what took him years to develop.

Sound quality
Listening was largely done with the Curious Evolved between a Melco N10 and various DACs. First impressions are of a pacey, open and detailed sound that’s sensitive to tempo and the texture of instruments and voices. It also images well, sounds are bold and three dimensional. On Bob Marley’s Natural Mystic the reverb on the guitar stands out and the leading edges of the bass line are well defined, leaving it full fat but tight, which Bob would have liked no doubt. 


It’s not as relaxed as the CAD cable used as a reference but also not as expensive (about half the price) and making a digital cable relaxed tends to add to cost for some reason. The Curious Evolved is more about engagement which it achieves with strong timing at the slight expense of tonal richness. Detail is well delivered and quieter sound of the drum toward the end of The Drycleaner from Des Moines (Joni Mitchell) really pops out. Another Mitchell track, Overture to Cotton Avenue, proved captivating, Jaco Pastorius’ bass positively oozing out of the system, making a dramatic contrast with the zing of steel strings on acoustic guitar, the latter embellished with lots of decay to define the space. The Grateful Dead’s Cumberland Blues is presented with lots of live energy, appropriately up tempo and revealing of just how tight this band was in the early ‘70s, they may have been hippies but they knew a thing or two about groove.

This Curious cable is about the same price as Vertere’s Redline and has a similarly enthusiastic sound but the Australian model emphasises texture to a greater extent and is a little smoother through the midrange which is a good balance to achieve. Brass instruments can often sound hard via digital systems but the Curious Evolved avoids this and produces good drive with shine on the brass that doesn’t become piercing, at least not through an Aqua La Scala MkII DAC. This combo worked very nicely and had me listening to Alice Coltrane’s Journey In Satchidananda for longer than expected, it’s not the sweetest of recordings but the music is cosmic if the system is gelling well.

The Curious Evolved USB is a welcome addition to the serious USB cable field, at the time of writing the price is equivalent to just under £400 which is competitive for a handmade cable. Those after a bit more get up and go yet appreciate the finer things available with streaming audio should find it right up their alley.


Type: USB digital audio cable
Conductor: annealed silver
Insulation: air
Shielding: only on ground & 5V
Connector: high conductivity USB A to USB B
Length: 0.8m
Diameter: 8mm

Price when tested:
US $550
Manufacturer Details:

Curious Cables
T +61 418 765 726


USB digital cable


Jason Kennedy

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