USB cables are still a “novelty”, although we use them for years connecting a printer, camera, mouse, keyboard, etc, to our computer, sometimes also portable players. So the USB cable became a part of the computer landscape. But the cables were never as stressed as ever before.
What is an USB cable? Such a cable is composed of two runs of cables in shields (four wires in total – the same number as there are connectors in the USB plugs) – one of those runs is used to transmit the signals, the other one is used for the 5VDC power supply. What does this mean? That one of the electromagnetic fields is disrupted by the other. This also means quite substantial vibrations of the structure, especially at the maximum power draw allowed by USB standards, which is 500mA, or 0.5A! Besides that, as we can read in the company materials, and what we can instinctively feel, a computer generates a lot of high frequency noise which comes out together with the voltage. This noise influences the closely placed signal cable, inducing its reflection in it. This influence is fought by shielding the cable runs. But this is only a half-measure. Acoustic Revive has a much better solution to the problem.
It is strange, that nobody before AR did not come to such a simple idea! It is sufficient to separate those two cables to get rid of most of the problems. We cannot separate them completely – on the side of the receiver, the USB DAC, or an USB-S/PDIF converter, we have one input, usually a type B (square) one. So when we split the cable to two separate runs, they have to converge there. It can be different on the transmitter side – most PCs, even laptops, have more than one USB port. So on that side, the cables can have separated plugs.
Mr. Yoshi Hontai, representing Acoustic Revive outside of Japan, send us both types of cables – the USB-1.0SP (with two plugs on the transmitter side) and USB-5.0PL (with single plugs). Both are made from two, separated, cables – one leads the power, while the other one the signal. The digits in the name represent the length of the cable.
To date we tested:
- Anti-vibration platforms RST-38 and RAF-48 HERE.
- Power strip + power cable AC RTP-4eu ULTIMATE + POWER REFERENCE HERE.
- Digital cable 70Ω DSIX/1.0 HERE
- Disc Demagnetizer RD-3, Grounding Conditioner RGC-24 HERE.
Recordings used in the test (a selection):
- Audio Accesory - T-TOC Records High Quality Data Master Comparison, TDVD-0002, DVD-R, ripy 16/44,1, 24/96, 24/192 WAV.
- Barb Jungr, Love Me Tender, Linn Records, AKD 255, FLAC 24/88,2.
- Brian Eno, Craft On A Milk Sea, Warp Records, WAV 24/44,1.
- Cassandra Wilson, Silver Pony, Blue Note, 29752, CD;
- Charlie Haden & Antonio Forcione, Heartplay, Naim Label, 24/96 FLAC.
- Chris Connor, Witchcraft, Atlantic/Warner Music Japan, WPCR-25166, CD.
- Depeche Mode, Ultra, Mute, DMCDX9, Collectors Edition, CD+DVD.
- Freddie Hubbard, Open Sesame, Blue Note/Audio Wave, AWMXR-0012, XRCD24.
- G. F. Haendel, Messiah (Dublin Version, 1742), Dunedin Consort&Players, Linn Records, CKH 312, FLAC 24/88,2.
- Harry Belafonte, Belafonte at Carnegie Hall, RCA/Sony Music, 7783322, LPCD-M2 Mastering, No. 0953, HQCD.
- Helge Lien Trio Hello Troll, Ozella Music, OZ021CD, FLAC 24/96;
- Jim Hall, Live!, Horizon/A&M Records/Universal Music Japan, UCCM-9225, CD.
- John Coltrane, Blue Train, Blue Note/Classic Records, HDAD 2010, DVD-V 24/96 + DVD-A 24/192 + FLAC.
- Stan Getz & Joao Gilberto, Getz/Gilberto, Verve, 24/96 FLAC.
- Stan Getz & Joao Gilberto, Getz/Gilberto, Verve/Lasting Impression Music, LIM K2HD 036, K2HD CD.
- Suzanne Vega, Close-Up, Vol 1. Love Songs, Amanuensis Productions/Cooking Vinyl, COOKCD521, CD.
- Zbigniew Namysłowski, Open, Polish Jazz, vol. 74, SX2539, pliki „master”, 16/44,1, 24/96 WAV.
Japanese versions of the CDs are available on CD Japan.
I used the Acoustic Revive cables in the test of all DACs with USB input I made during the last five months. As it turned out, the length of the 5m long USB-5.0PL is a problem for some of them – the computer signals then a problem with installing drivers and reports a fault of the hardware. This is a problem of the receiver, and not the cable, but eliminates the usage of such long cables in that case. I think, that about 25% of the devices had this problem. I never had any problems with the USB-1.0SP.
Already the first impression made by the cables, with their construction, looks and overall sturdiness is good. The same thing can be said about the sound – despite the fact, that some engineers and people related to the computer branch tell, that an USB cable should have no influence on the sound. But it is enough to prepare a sensible listening session to hear that it does have influence, and a big one.
We should remember, that short, quick listening sessions can be deceiving. And although the so called “first impression” does count very much, but only when we know where to search for from the very beginning and we do not need any time for accommodating to a given sound. In case of USB cables, or actually in MY case, it was different with the USB cables.
Changes brought by the USB cable are clear and unanimous. I know the standpoint of fellow engineers and I respect them. In short it tells that a well made digital receiver, and a USB receiver even more, should counteract jitter and minimize all RF noise brought by the USB cable. Yes I know, that this is a strong standpoint. But as usual I believe most of all in that what I hear – surprisingly often observations made engineers revise theories and look at the problem from a different side. I think, that in case of digital connection, USB being one of those, it will also happen.
I did not yet come across a coherent description of the changes, with which we deal in such cables. And I am not talking about modification brought by individual cables, converters, etc, but about an attempt of capturing something more general, something what – in my opinion – repeats each time, and what defines the requirements for the better cables.
A lesser cable (converter, USB DAC) washes out the sound stage. This is probably the strongest signature of bad USB sound. This is not the kind of washing out we know from less good loudspeakers, but something deeper – there is some kind of diffusion, as if the basic sound, that what describes contours of the sounds would have been dispersed around the room. This results in a less stable and often unclear contours of the sound. There is also no such thing as depth of the stage – everything is flattened and less dynamic.
Because dynamics is a discriminator of a “worse” (in an absolute scale) cable (etc). Dynamics is like a precision gauge for jitter – the higher the jitter, the worse the dynamics. It is surprisingly easy to show, that even USB receivers with asynchronous signal reclocking are very sensitive to the quality of the cable and source of the signal. With a lesser combination dynamics falls quickly, exponentially.
And finally resolution. Here the case is clear and simple – going to a better cable we get more sound and more individual sounds. Those three things together, although I quantify them, are a manifestation of the same problem, are a precise indicator of the fact, if the USB cable (transmitter, receiver, etc) is better or worse.
Interesting is the fact, that the case of the timbre is more complicated and not as unanimous. In case of a laptop as a source we cannot talk about such a solid repeatability and homogeneity of playback, as we can in case of a CD, what is the reference point for all audio gear designers, and that due to the repeatability of the sound. A computer is different, because each session is affected by lots of elements, starting with the settings, kind of files used and ending with the actual load of the microprocessor. This is why I do not quote timbre as one of the differentiating elements. Yes, the better the cable, the more transparent and less coloring for the sound it is. But those changes are not as coherent as those I quoted in the beginning.
Acoustic Revive cables are ones of the most transparent I know. I mean they are the best in that aspect, but – please see above. They fantastically show the issues with Verve high resolution files, available on HD Tracks. For example with the disc Ella Fitzgerald & Louis Armstrong. I know very well the version issued on SACD – and I never liked it. It was dry, bright and not really enjoyable. As it turned out, the DSD material was prepared by converting from PCM 24/96 signal, which is the current digital master tape. And it is not a good transfer. Most Japanese versions of this disc (CD!) are far better. I can say the same about the disc Stan Getz & Joao Gilberto Getz/Gilberto. Maybe you can remember the reaction of the KSS members – most of them chose the 16/44.1 files prepared by the company FIM, rejecting the 24/96 files made by Verve (description HERE)? This is exactly what I am talking about: the engineers of larger companies do not fully understand the nature of hi-res files, as if we would have to repeat all the errors related to the CD.
Like I say, the differences are very painful. Some of the USB cables cover this up, I mean, they modify the timbre in such a way, with a slight limitation of resolution and precision, that after a short listening session, a listener can point to cables like the Furutech GT2-B, or Wireworld Starlight, with which I compared the AR, as the better ones. Especially the Furutech cable makes a trick, which will make many music lovers happy listening to their recordings – it underlines the lower midrange, while losing a bit of the resolution, not showing a strong attack. At first we think, that this is better. But when we compare it with another, non-USB source, we can see that this is a trick, something that draws our attention away from the source signal by changing it – warming, extinction, minimizing the amount of details. This can be heard from the purist digital recordings, made especially for the 24/96 or 24/192 resolutions.
The AR cables are just painfully accurate. If I would own a recording studio, then I would like to know exactly, what I have “on tape”. At the same time I want to know what kind of file I am playing at home, and not only have an approximate idea of it. The Japanese cables are very dynamic and resolving. They draw the contours vocals and instruments phenomenally. They show a fantastically resolving treble and splendidly controlled bass. The latter is especially surprising. The loudspeakers I use now, Ascendo System ZF3 SE have a very coherent, strong and quick bass. It seemed, that everything in the bottom octaves sounds like that, and that this character is imposed on each and every disc played. Comparing the Furutech and AR showed, that this is not true, that the Furutech washes out the bass, that the bass drum reverbs too long, losing the rhythm of the pieces. This is not a flaw of the Furutech, this is an inexpensive, and in its price range splendid cable, but it shows what it all is about, and what can be achieved with a good USB cable.
This is how those cables sound. They are very resolving and transparent. They do not warm or thin the sound – except for one moment: the Furutech has slightly more saturated midrange, and with many USB DACs up to 2000-3000zl, such character of sound will seem more appropriate. I will not blame anyone, because I partially agree with that. But this is a problem of the DAC and not the AR cable. The latter just tries not to interfere in any way. But maybe, with another generation of their cables Acoustic Revive will boost it a little? I would not complain about that.
Except for that, I do not see anything I could criticize. This does not mean, of course, that this cable has no flaws, but only that on this stage of development of sources related to USB my knowledge is limited, and I never heard anything better. I say, I do not know anything better, but I am sure, that something better will be made in time. But here and now, the AR are state-of-the-art among USB cables.
The Japanese cable are stiff, and do not allow to connect them easily. With some good will and effort we can connect each device with them, but sometimes you have to make some compromises regarding placement of the DAC, especially when it is small.
From outside the cables look very professional – metal, gold plated plugs, nice mesh and most of all – two runs. This is the clou of their construction – the cables for the signal and those for 5VDC are separated. The cables are completely made in Japan, including the conductors. They are made from very thick (hence the stiffness) solid core cables, with a cross-section of 0.8mm, using PCOCC-A copper. As it is underlined in the company material, those are the thickest conductors that can be used in USB cables. Classic cables usually have a cross-section of 0.2-0.3mm. The cables are 100% shielded with a tightly wound copper tape. The plugs are made from aluminum slabs (‘air craft grade’) 2017S, with low susceptibility to resonance and high mechanical resistance. The external dielectric is a tube with carbon fibers called “Carbon SF”.
USB-1.0SP – is a cable with one plug on the receiver side (in my case type B; the receiver is of course misleading, as USB is a bi-directional communication, but it is easier for me to describe things that way) and two plugs from the source side (in my case type A). This means, that we need to have two free USB ports on our computer, and in addition those ports need to be close together - the cable is stiff! On the other hand, the USB-5.0PL is a slightly simpler cable, with single plugs on both ends.
SEKIGUCHI MACHINE SALES CO.,LTD
Gunma Pref. 372-0812 JAPAN
President: Mr. Ken Ishiguro