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Light Harmonic LightSpeed USB cable meta-review

  • Call me a coward if you like but I’ve been holding out on writing this post. Reviewing cables tends to attract a lot of unless-you-prove-it-with-a-double-blind-test-your-conclusions-are-invalid comments. Having said that, I was encouraged by the reader civility that met my previous cable review, that of Mike Morrow’s MAP-1. But that was for a power cable that sells for US$149.

    Today, I wanna big up a USB cable that sells for $999.

    Yes, you heard me: USB cable. One thousand dollars.


    The LightSpeed USB cable comes from Californian’s Light Harmonic – the same guys that make the $30K Da Vinci endgame DAC and the same guys that Kickstarted a $300 DAC/headphone amp called Geek. I guess they like to work BOTH ends of the money rope.

    A standard length is 0.8m.  1.6m will run you US$1399, 3.8m is US$1999.

    By physically splitting the 5V power feed and the digital audio stream, the LightSpeed seeks to minimise the former exacting electrical disturbances on the latter, which would cause timing errors – jitter.

    Some maths: the LightSpeed promises 20x the bandwidth delivery of USB 2.0’s 480Mbit/sec. cables. 20 x 480 = 9600Mbit/sec = ~10Gbit/sec.

    If you’re the kind of person that gets off on deeper technicalia, check out Steve Plaskin’s review of the LightSpeed over at AudioStream. I read Plaskin’s review, agreed with pretty much all of his conclusions and dusted off my hands as if to say, “nothing more for me to add”.


    Wait. I’m getting ahead of myself…

    I first picked up on the significance of the LightSpeed USB cable’s improvements when playing switcheroo with USB DACs a couple of months ago, initially (and mistakenly) attributing better separated detail to the Resonessence Labs Concero HP. Replicating this game-lifting with a couple of other DACs sealed the takeaway container: this USB cable brought improvements far larger than anyone might reasonably expect…

    …and then you look at the US$999 price tag again. Entry-level it ain’t.

    Yes, the increase in tonal density is greater than that brought by iFi’s iUSBPower. In this context, the USB cable amelioration is price commensurate.

    A thousand dollar USB cable probably won’t be set to work with a thousand dollar DAC. You’d be better off buying a two thousand dollar DAC. However, if you’ve got a $5kish decoder, the LightSpeed is well worth a look. I’ve now got it running direct out of a MacMini and into Resonessence Labs’ flagship INVICTA Mirus. Does it bring improvements? Yessir.

    Plus, I really dig red cables.


    Last week came a 6Moon-ing group email from Srajan Ebaen: Paul hits us with a SOTA USB cable he sez makes more of a diff than speaker or interconnect cables.

    I hit Srajan right back for a one-to-one: I have one of those LH USB cables and I agree with Paul – bigger diff than speaker or interconnect changes.

    Srajan: Fuck. You mean I now gotta get me one of those things? Geezus. Thanks a lot -:)

    Me: ‘Fraid so.

    Srajan: Okay then.

    Skeptics, run at me.

    Further information: Light Harmonic

    John H. Darko

    Written by John H. Darko

    John currently lives in Berlin where creates videos and podcasts and pens written pieces for Darko.Audio. He has also contributed to 6moons, TONEAudio, AudioStream and Stereophile.

    Darko.Audio is a member of EISA.

    Follow John on YouTube or Instagram


    1. Fair enough… Thanks Darko.

      Isolating 5V power from the signal leads makes sense to me.

      But… you’ve got to get your hands on a RC1 Geek for a pro type review. Can’t wait until January….

    2. As long as this isn’t the beginning of a downward spiral into endless cable reviews I’ll forgive this indiscretion.

      • They will be VERY few and far between. Reports on cables will only be forthcoming when surprise results transpire.

      • “As long as…”
        What are you, his mom? Let the man do his job. Either you trust his ears or you don’t. If you have no interest in what he’s reviewing at the moment, then just simply skip it and wait for the next review.

        • Thanks Simon – it really is that simple (although I don’t think B-Dub was having a pop).

    3. I really do not understand why all the audio industry and ‘experts’ are so in love with USB for interconnecting a computer with a DAC…
      There is a much better solutions than this industrial USB ‘marketing’ standard and it is the I2S – I2S connection via an HDMI cable . I do not understand why audiophiles can accept for a less-than-perfect solution with this USB protocol and the need for exorbitant cables like this one.

      • Nope. There are two versions of this cable – the version reviewed here is the standard one with single terminations at each end.

    4. Why compare to the iUSB Power and not the Gemini cable? Also, didn’t I read a report somewhere where they said that the TotalDac €350 USB cable was even better than the Light Harmonic cable? I think it was at Audiostream wne they reviewed tye TotalDac.

    5. Mr. Darko considering your view on the Lightspeed USB cable…. would you recommend this over say an Audiophilleo 1 or 2 w/ pure power? Trying to get a read on where you see the impact of improvements.

      (He asks while quietly lighting the igniter on his flamethrower).

      I personally buy in the sub $100 range for cables… mostly for aesthetic value…. but to each his own…. some fixate on boxes, aluminum faceplates, glass tubes, or designer capacitors, others tweak on speakers and cherry veneers, others obsess over stone wood and metal plinths, itsy bitsy $500 needles, tonearms, belt driven platters, some dig brass cones and aluminum and glass stands and racks floating on magnetic fields…. others dig ‘out of production’ R2R dacs or Sigma Delta…. some others dig cables… to each his own.

      I’d be lying if I tried to say their isn’t a consumer mad man inside me who lusts after certain gears when he sees them, try to deny it with the old saw “I don’t care how it looks as long as it sounds good.” BULLLLL SSSHH!!!!%%%% I know I get obsessive about equipment… but as long as my love of music and CD purchases and downloads don’t fall into the shadows of Mr. Gadget Obsession Consumer then I am good.

      If someone has the means and enjoys something like a $1k USB cable. It’s their cash, they are a grown man, they earned it… they can spend what they’ve earned however they want. I could certainly spend it better but…. It’s not my call.

      • The AP2 (even flying solo with no PP) would still bring more of an improvement than the Light Harmonic cable. The latter is what you buy once transport and DAC are sorted.

    6. BS! It’s all just 1 & 0!!! Just kidding. Just giving the haters a little boost.

      Thanks for the review, enjoyed it. I have a fetish for USB cables, or digital cables for that matter. It’s nice to see cables review here, and I hope to see more of it, although I totally understand what you say about the Jekyll and Hyde transformation that goes on in (some) people when they hear about cable reviews.

      I guess the question would be. Is the difference between this good 1k cable as big as the difference between a good 20 dollar cable and a good 200-300 usb cable? Since I haven’t tried any USB cable over $600.00 i can’t answer the question.

    7. Bill Leebens working with Light Harmonic already has dispatched me one of these to me as well – 1.6m, double header. It’ll be high noon in the USB corral and mano-i-mano against my usual KingRex dual ender which until now — I’ve admittedly not done too many USB cable comparisons — was/is my favorite. One thing to appreciate about the genre in general is that digital signal transmission is about square waves. That’s quite different from analog cables and why one can’t simply use an analog interconnect, slap on a pair of BNC ends, call it a digital cable and expect the best. I do rather think that high-speed digital transmissions are a very different cat to skin which leaves many of the usual hifi cable makers out in the cold who, more or less, repackage analog cable designs as digital and call it a day.

      • “That’s quite different from analog cables and why one can’t simply use an analog interconnect, slap on a pair of BNC ends, call it a digital cable and expect the best. I do rather think that high-speed digital transmissions are a very different cat to skin which leaves many of the usual hifi cable makers out in the cold who, more or less, repackage analog cable designs as digital and call it a day.” <--- I know Chris Sommovigo would agree. 🙂

    8. thx Darko
      One of the earliest USB cables with separated power and data lines is the USB cable from Revelation Audio Labs. I heard it and it made a very good impression with me compared to the Locus Design Nucleus v2 cable
      It would be nice if you could review it especially since its 40% lighter price 🙂

      • Thanks Kyrill. Do you have a URL?

        I don’t think my schedule of other hardware will permit another USB cable review at this stage. And if it does, I’ll be doing the iFi Gemini.

    9. The website is and I would not be surprised if you would like to keep it…
      I could not find one unfavorable review about that cable in the many audio forums. I never heard about it until I learned the cable is highly recommended by Steve Nugent from Empirical Audio, who advises that cable for his OffRamp 5 USB/SPDIF converter.
      Keep up the good work Darko, Tone Audio and 6moons next to Postive Feedback and Stereotimes together with Digital Audio Review are my 5 reference web sites for high end audio :))

      • Thanks for the extra info and kind words Kyrill. Steve Nugent’s vote of confidence carries considerable weight.

    10. just got a lightspeed usb cable in the mail yesterday. still burning it in, but i can confirm the hype – it is spectacular. want to echo what the others are saying, $1K is a lot for usb (or any) cable, but you will get a lot more from this $1K than you usually do in audio. two thumbs way up.

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