Your Final System Reference USB cable - $350 1METER

Kingrex UCraft (Y) cable.  $599 2 METERS

Review by

Dr. John Richardson

A Tale of Two (Make that Several) Cables: A Look at High-End USB Cables and DAC Power Supplies



There can’t be much of anything less interesting in high end audio than the lowly USB cable.  I imagine that most folks who go to the trouble of purchasing their first USB DAC just interface it to their computer with any old USB cable that happens to by lying around, or maybe with the throwaway one that probably came in the box with the DAC.  I mean, why not?  The purpose of the cable is so mundane.  It’s transporting BITS for heavens sake!  That’s right, ones and zeroes.  Heck, inebriated college kids can tell ones and zeroes apart, so it also ought to be a cinch for any stock digital cable.


Hold on a minute, though.  Have you taken the time to think about HOW those bits are transferred from your computer to your DAC?  Yes, it’s digital data traveling along in the analog domain... That’s right, encoded as voltage or current pulses moving down a wire, very much akin to the analog waveforms that travel through analog interconnects and speaker wire.  Sure, the DAC only has to recognize a HI or LO voltage state that corresponds to a one or a zero, but just like any other case with analog signals, timing and distortion matter.  If there is any lead or lag, then the music gets muddled (or is it muddied)?  Either way, the result is probably not going to be favorable to the well honed ears of audiophiles.


So then, why is timing so important?  A simple answer lies in the fact that the receiver (DAC) calls the incoming pulse as a one or zero based on its leading or falling edge.  If this edge is poorly resolved, then so will be the timing of our music.  What suffers? Pretty much everything that we audio nuts hold dear:  pace, timing, rhythm, soundstage, imaging, tonality, harmonics... you name it.  Sounds to me, then, that the very same concerns that we obsess over in analog cables should also apply to digital ones such as USB cables, as pulse edge resolution would be affected by typical cable properties such as resistance, capacitance, and inductance, as well as improper shielding against RF hash.



Now that I have your attention, let’s review the architecture of the typical USB cable a bit.  The cable is separated into two different types of conduit:  one for transfer of digital data (as we just discussed), and one to sustain 5 V DC to power downstream components.  Yes, we also use the USB cable as a power cable... This revelation in and of itself can be something of a game changer.  Even if our DAC isn’t powered through the USB cable, that voltage is still there (keep in mind that some DACs, typically less expensive ones, are indeed powered by the computer through the USB cable).  Aren’t we  taught never to run our cables parallel to one another and to keep power cables as far away from our analog interconnects as possible?  Well, here inside the jacket of our USB cable, we have a POWER CABLE running the full length right beside our data cable!  OK, I’m jumping the gun a bit here, as the power supply leg is only 5 V DC as opposed to 115 V line AC.  Even so, that power coming from the computer is dirty power, hashy and poorly regulated.  We do want to protect our sacred bitstream from that travesty as much as we can, don’t we?


This is why a carefully designed and executed USB cable is important.  As I have said many times before, in computer audio, everything matters.


So then, let me now introduce the two premium USB cables that are the subject of this review:  the Your Final System (YFS) Reference USB cable, and the Kingrex UCraft (Y) cable.  These go for $350 for the one meter YFS cable and $599 for the Kingrex, which is two meters in length.  Both have that nice, overbuilt feel that the consumer would expect at this price point, but differences are also immediately apparent.


The YFS Reference is thick and stiff, like a well built and shielded interconnect.  I like this type of quality, but sometimes USB cables have to contort in weird ways to make the connection between computer and DAC.  Here, I found the YFS cable a bit hard to work with due to its stiffness... It just sometimes didn’t want to bend or twist.  Not a complaint, so to speak, but definitely an observation.  Maybe more length might have made it feel a bit more pliable.  In contrast, the Kingrex cable was more ribbon-like, which made it seem more agreeable to making the necessary turns to get from point A to point B (or is that to get from A-type connector to B-type connector?).  Another feature of the Kingrex cable (hence its name) is that it is constructed as a “Y”.  Yep, it’s bifurcated.  The advantage here is that the A-type connector (which goes to the computer) is really two A-type connectors, each at the end of about one meter of cable.  Picture a two headed snake, and you’ll sort of have a mental image of what I’m talking about.  Why do this?  Well, the short answer is that it separates the power supply leg from the data carrying leg such that an external power supply can be used, provided your DAC is USB bus powered in the first place.  Now the possibility exists to eliminate the dirty 5V supply from the computer altogether.  Of course, not to be outdone, a quick check of the YFS website shows that its reference cable can also be purchased as a data only cable, also for $350 per one meter, thus eliminating the power supply leg altogether.  Be aware that your DAC must have its own internal power supply if you decide to go with this option.



Sonic Impressions


My evaluation setup on the digital side was a bit different from that used in prior reviews, as the USB cable itself was to be the focus of my listening experience.  In most cases, I have opted to feed data to my DAC, typically an Antelope Audio Zodiac, by way of its coaxial S/PDIF input with my Sound Devices USB Pre2 serving as a USB to S/PDIF converter.  Here, I wanted to minimize the steps in the digital chain and get the USB cable as close to the DAC as possible.  Since my Antelope DAC uses a mini-USB connector, it was out of contention.  Fortunately, during the trial period, I received the new Rein Audio X3-DAC, which does employ a well-designed asynchronous USB input.  While the YFS cable worked wonderfully with that DAC, for some reason I couldn’t get the computer to recognize the Rein Audio DAC with the Kingrex cable, so that option was out. 

My last option was to use the only other USB DAC in the house, which was my trusty Sound Devices USBPre2.  While not at the sonic level of either the Antelope or the Rein Audio units, the USBPre2  is not a bad little DAC.  Music from its analog outputs when used as a USB DAC is detailed, tuneful, and altogether warmly easy on the ears.  So the USBPre2 it would be for all comparisons, if only by default.  Computers used were either my MacBook Air, which has the advantage of solid state internal memory, or my normal Mac Mini.  I used iTunes in conjunction with Pure Music (as always) for all audio playback. On the amplification side, I used my typical REDGUM RGi60ENR integrated amplifier powering either Shahinian Compass, REDGUM Manna, or Fritzspeaks Revelation 7 speakers, as well as an ODL HT-2 amplifier driving my Shahinian Double Eagle subwoofer (when used).


Let me begin by emphasizing that both of the cables under review here are sound-wise a country mile ahead of the stock USB cable that comes with most digital gear these days (including many USB DACs out there).  At the end of my critical listening sessions, I decided to put in a typical “freebie” cable and see what would happen.  As expected, it allowed the bits to flow from computer to DAC, and acceptably satisfying music issued forth.  However, in comparison to both of the high-end cables, tunes sounded veiled, clouded, and unengaging, without the specific soundstaging or rhythmic flow offered by the other cables.  I felt that I was listening through a murky haze as opposed to a real event.  In short, my advice to anyone using such a cable and expecting high-end sound would be to replace it immediately, and with anything that’s better (i.e., I don’t think you have to necessarily spend a stratospheric amount of money on a USB cable to get audible improvements; if you can do nothing else, at least invest $20 in a Belkin Gold series USB cable).


So let’s allow the real stars of the show to strut their stuff then...


I can say that I expected to hear improvements over what I normally get when I listen through the USBPre2 DAC.  What I didn’t really expect to hear were substantial differences between the two cables, and here I came away surprised.  In the ideal world of perfectionist audio, we expect really good cables of any sort to step out of the way and add as little sonic signature to our music as possible.  But we live in the real world, where in a highly resolving system, any cable will inject at least a bit of its own character into the mix... And that’s exactly what I got.


I’ll start by doing my best to describe the characteristics of the YFS Reference cable.   I found this cable to be quite easy on the ears, offering a nuanced and well-fleshed-out harmonic presentation.  It never seemed in a great hurry, and it didn’t tend to emphasize leading edges of transients as emphatically as the Kingrex cable did.  What it did do, however, was let me bask in the radiant glow of the complex harmonic overtones of instruments and voices by allowing notes to decay in their own sweet time into a nearly infinite nothingness.  This was especially true when listening to Ahmad Jamal’s artful piano playing on the album “Happy Moods” (24 bit/88.2 kHz digital transfer; Argo stereo LP).  As my friend Mike Peshkin likes to point out, Jamal has an uncanny sense of rhythm and timing

which translates into an effective ability to build up and release tension at the keyboard.  He also coaxes a lovely palette of tonal colors from his instrument which was very well served by the harmonic presentation of the YFS cable.  The decay of notes was just lovely on tunes such as “Excerpt from the Blues.”  I also greatly appreciated the tonal richness and overtones of Gary Burton’s vibes on the album “Like Minds” (24 bit/88.2 kHz digital download, HDTracks) as well as the balance and decay of the ride cymbal throughout the album.  I could close my eyes and easily visualize the ride cymbal pushing slightly inward with each brush of the drumstick.


The YFS cable also did an outstanding job of inserting physical space around performers on good recordings such that I had the satisfying illusion of them playing in a real three-dimensional space, as was readily apparent on both the Jamal and Burton albums.


Another recording that I have been enjoying lately is Led Zeppelin’s reunion concert “Celebration Day” (24 bit/48 kHz digital download, HDTracks), which to me sounds almost like a perfect reincarnation of the original band from days of yore.  These guys have definitely not lost their chops, maybe with the exception of Robert Plant, whose vocals don’t quite hit the highest registers of his youth.  Even Jason Bonham somehow seems to sound the nearly perfect clone of his old man on the drum set. 

While I am not the biggest fan of the group’s most modern rendition of the classic “Stairway to Heaven,” the rest of the album just plain rocks like there’s no tomorrow.  We are indeed fortunate to have this live event as captured using today’s advanced recording technologies so that those of us who were too young (or just not fortunate enough) to have experienced the real thing can get a taste of what a live Zeppelin concert must have been like.  I suppose that not all audiophiles will be happy with this album because the bottom end (i.e., electric bass and kick drum) comes off somewhat muddy, fat, and sloppy when compared to what we would expect to hear from a cleaned up studio recording.  Hey, have you ever been to a real rock concert in a large stadium venue?  Well, if you have, you will know that that’s how the bass really sounds, and this recording gets it right!  With the YFS cable on the scene, the kick drum emanated thwacks that you more feel than hear, and bass notes coming from the PA system mingled readily with echoed reflections from God knows where.  All in all a soupy mess of bass, but oh so satisfying nonetheless!


I suspect that those who like to wallow in the complex harmonic textures of live, un-amplified music will very much appreciate the sonic smorgasbord offered up by the YFS Reference USB cable.


On the other side of the spectrum we have the Kingrex cable.  To keep the comparison fair, I connected both A-type ends of the cable into two separate USB ports on my computer, as the USB Pre2 is USB bus powered.  This contender will no doubt appeal to listeners who like their musical presentation to focus on snap, rhythm, and x-ray like detail. If the YFS cable seemed a bit pokey, the Kingrex was the equivalent of Usain Bolt blasting out of the starting blocks.  This cable was all about emphasizing leading edges of notes and seemingly early truncation of trailing transients.  I didn’t feel that there was much time to slow down and smell the roses while listening, as the notes seemed to issue forth in feverishly torrential bursts.  I don’t mean for this to imply that the cable sounded bad, as this presentation lent a lot of energy and excitement to the listening experience.  While plenty of harmonic and tonal information was present, notes weren’t as leisurely fleshed out as they had been with the YFS cable.  Cymbals, for example, had more of a metallic sheen and immediacy when struck, whereas with the YFS cable resulted in more of a burnished bronze sort of presentation with lots of complex overtones.


If a particular cable were to be ferreted out for providing a seemingly more detailed and resolved presentation, it would have to be the Kingrex.  Lots of information here, especially on the front end of the note.  This sort of thing was nice on the Jamal album, as it served to showcase the sense of timing that is so important to his playing, but I missed the emphasis on the harmonic decay that the YFS cable provided so effectively.  That sense of speed and detail was also well appreciated on the Zeppelin Celebration Day album, in that it gave a bit of welcome edge to Robert Plant’s vocals and Jimmy Page’s lead guitar.


With respect to spatial presentation, both of these cables were excellent, carrying the banner well out ahead of typical stock USB cables, as mentioned previously.  Using the higher end cables, I was rewarded with a wide and deep soundstage, with a good illusion of air and space around individual performers.  The collapse and woolliness of the soundstage using the stock cable really shocked me in comparison, especially knowing what my ancillary gear is capable of in this respect.  Given that the USB cable would be about the last thing that most people would think of upgrading, I have to wonder how many folks out there have been turned off by computer audio when using a cheap and poorly made digital cable.


Given that the USBPre2 receives its power directly from the computer via the USB cable, the option that I really wanted to explore was the use of an external DC power supply coupled with the bifurcated Kingrex cable.  In anticipation of such an event, I had asked Carol at Kingrex to send me their battery supply, dubbed the UPower.  This little guy, which was part of my review some time ago of Kingrex’s UD 384 DAC, provides 5 V DC through an “A” type connector of a USB cable.  I found that its use definitely raised the level of performance of the Kingrex DAC relative to powering it directly from the wall using its cheap wall-wart supply.  Problem was, it didn’t appear that the folks at YFS offered a Y cable that could accommodate the UPower unit, so I really didn’t want to discuss this option as part of this review.  As luck would have it, however, I was recently asked by Kevin O’Brien at YFS if I would like to hear their version of a bifurcated “Y” cable, which apparently they do make; it sells for $475 for a one meter set and $650 for a two meter run.  Now we’re talking!  A direct comparison of “Y” cables from both companies using Kingrex’s battery powered supply was now possible.  The dirty power from the computer could now be bypassed altogether when using the USBPre2, thus potentially bringing it to altogether new levels of performance.


As expected, both the YFS and Kingrex “Y” cables yielded improved results for the USBPre2 when used with the Kingrex UPower supply, though each manufacturer’s cable to a great degree preserved its sonic signature as described earlier, just now with fewer deleterious effects.  Either way, the Sound Devices DAC sang like it never had before, bringing it more on par with much more expensive compatriots.  I got clarity and timing with lots of resolution, presumably due to the lowered noise floor of the power supply.  The result, in short, was greater musicality from the DAC and greater involvement on the part of the listener.  Of course, improvements are incremental and come at added cost, so here is where I have to put my Stereomojo value conscious hat on.


Wonderful as all of the improvements were from the two “Y” cables with the battery supply, using this configuration with the USBPre 2 does call into question a value judgement in that the cable and power supply together cost potentially more than the USBPre 2 itself does!  My mind went wild with possibilities though... What would happen if I used the USBPre 2 with a “Y” cable and power supply for ripping vinyl?  Would my digital files sound better?  I did try this, and my conclusion is that there isn’t enough improvement here to justify the cost, primarily due to the relatively high noise floor of vinyl itself, which seems to negate the perceived drop in the digital noise floor.


Was one manufacturer’s cable “better” than the other from a listener’s perspective?  That’s a tough question to answer.  In my case, it really came down to which speakers I was listening through at the time.  The Fritzspeak Revelation 7s are very fast and detailed with exceptional neutrality; in this case I found that I preferred the YFS “Y” cable in that it helped to flesh out harmonics and add some extra warmth and body to the music.  With the Shahinians and the REDGUMs, which are a bit warmer and less rushed, the Kingrex added a bit of welcome energy, verve, and excitement.  As always, it comes down to ancillary equipment and personal preference.  By all means, try to listen before you buy, as this kind of cable needs to be looked at as more of a long term investment in your system than a mere accessory.


OK, stop the presses (yet again)!  If this review seems to you that it will never end, you’re not alone.  One final twist in our never ending story must be mentioned.  Not to be outdone, I was informed by Michael O’Brien, the analog guy of YFS, that they, too, manufacture a 5 V DC power supply utilizing a USB type “A” connector as its output.  Unlike the Kingrex UPower, this device is a highly regulated linear supply that operates on 115 V AC, as supplied at your wall.  That’s right, you just plug it in and go.  I like this approach better than a battery supply because there’s not recharging involved.  Occasionally I’d forget to flip the switch on the UPower to the recharge position after a late night listening session only to find it dead as a doornail the next morning.  Silly me.


As good as the Kingrex UPower unit is, I have to say I preferred the linear YFS supply when driving the USBPre2.  I suspect that it is capable of supplying considerably more current to its load than the Kingrex can, and this resulted in the music having a substantially more solid footing and foundation, which helped both in terms of timing and flow, as well as providing improved body and substance.  It was like listening to my USBPre2 turbocharged!  Of course, I need to note that the Kingrex supply costs only $189 versus $900 for the beefy YFS supply (though YFS will knock $100 off the price of the supply if you also purchase their Reference “Y” cable at the same time).


Given that the improvements offered by these high-end USB cables were obvious to me using an inexpensive DAC, then I do believe that they would be a very good value for someone looking to get the best possible performance out of an expensive USB DAC.  Look at it this way:  using a very good DAC with a throwaway USB cable is the equivalent of putting crappy tires on your tricked out Bimmer... Think about it.




Surprise, surprise, surprise!  High end USB cables really do make a difference...


Each cable tested was indeed a marked improvement over the cheap “throwaway” USB cable I compared them to, but does the difference in cost merit the purchase of such a cable?  Well, that’s up to you to decide.  If I had a lot of money, I’d be in line to buy one myself; they can offer very real sonic improvements based on my experience.  Your own mileage may vary, as they say, so I’d advocate experimenting with a few of these cables in your own system if you can before you commit.


My short wrap-up:  go with the YFS cable if you relish harmonic purity and focus on the decay of notes; opt for the Kingrex cable if you feel the need for speed, but don’t mind your music a bit on the hyper detailed side (or if your system needs a bit of a turbo charge).  I also found generally that the “Y” configuration was better sounding than the normal “linear” architecture, and if your USB DAC is bus powered, then this choice becomes a no-brainer if you can also spring for a good 5 V DC linear or battery operated power supply such as either of the ones reviewed here.



Back to other audio reviews