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Next level USB audio with UpTone REGEN, Curious cables

  • Asserting that not all USB transmission methods are born equal means dropping a few C-bombs. Apologies run in advance.

    The theory – that it’s all ones and zeroes, end of story – tells us that the cable shouldn’t matter as long as it meets the USB specification. In its simplicity lies attractiveness. Listening to different types of wire, from the cheap to the downright opulent, tells us otherwise. That spells Controversy. Crash!

    Then there are those would sooner lean on theory over experience to prop up their prejudice. That spells out a second C-bomb: C____ (five-letters and unmentionable here). Readers are left to fill in their own blanks. Bang!

    Our third C-bomb points us at a different type of listener: one with an open mind. If s/he hears it, s/he hears it. If s/he doesn’t, s/he doesn’t. That spells Curious. Wallop!

    He of Queensland, Rob Woodland’s USB cable of the same name KO-d this commentator not two months ago.

    More recently, Srajan Ebaen’s 6moons investigation into the Curious USB cable‘s audible efficacy concluded with similarly positive affirmation: that Woodland’s wire restores inner spacious, depth and micro-dynamic sparkle to digital audio playback. US$380 gets you onto the starting blocks with a 0.8m length. Add US$40 per incremental 20cm.

    What of subtraction for a shorter connection?

    Despite not (yet) meeting with the formal review treatment, UpTone Audio’s USB REGEN has become this commentator’s preferred USB data line sprucer. My own cash went down on the USB REGEN blind in August and since then the Californian device has come up top trumps over both the Schiit Wyrd and the AudioQuest JitterBug – more expensive than both at US$175, one would jolly well expect so.


    In the simplest of terms, the USB REGEN is a USB 2.0 hub but as one might expect from designer and all-round digital audio guru John Swenson, its remit runs much deeper.

    Readers needing the full skinny on what it does and how it works are directed to the Swenson Explains section of UpTone Audio’s website but I’ll attempt to expand on some of what I (hopefully) understand about the USB REGEN’s workings.

    The Uptone device takes a three-pronged approach to improving the USB datastream’s quality. UpTone refer to it as signal integrity:

    1) complete USB data signal regeneration (hence ‘REGEN’);

    2) a low-noise power supply replacing the 5V feed from the host device;

    3) better USB line impedance matching.

    The latter is one of the reasons why the USB REGEN sits closest to the DAC. Note that the (passive) AudioQuest JitterBug plugs into the host computer’s USB port whilst the Schiit Wyrd sits somewhere in the middle and requires two USB cables. So too does the USB REGEN; we’ll get to that shortly.

    This video details connectivity specifics for beginners:

    Digging deeper we learn that data is despatched from a computer’s USB port not as a constant flow but in bursts. Those bursts can cause electrical (packet) noise. Sitting between USB port and DAC, the REGEN captures the incoming USB signal and regenerates it with higher ‘signal integrity’ such that its less bursty (and less noisy) and therefore more easily read by the DAC’s USB receiver chip to which the USB REGEN is (almost) directly connected.

    Why does this matter?

    Faced with a noisier incoming feed – i.e. lower signal integrity – a DAC’s USB receiver chip must work extra hard to ensure the incoming analogue voltage pulses (that represent digital ones and zeroes) are read without error.

    Additional data-read demands can cause the PHY – the USB receiver chip’s first point of contact – to activate additional layers of pre-processing circuitry, in turn causing an increase in electrical noise inside the DAC itself; the exact thing we’re trying to eradicate.

    Conversely, faced with better signal integrity the PHY’s pre-processing circuits sit it out; which lowers noise.

    The takeaway: noise inside the DAC is dependent on the quality of the incoming data signal.

    Enough theory.

    In the Uptone USB REGEN’s box, a 19cm USB fly-lead is for those who can’t (or won’t) allow the REGEN to hang free n’ easy from their DAC’s USB port via the shorter-signal path of the supplied USB A-to-B adaptor. During a long telephone conversation with Uptone’s Alex Crespi some weeks ago I recall him saying he’d spent a good amount of time finding the ‘right’ adaptor.

    And there’s no mistaking the Uptone USB REGEN’s ability to massage away some of the tension and hardness so often heard in digitally fronted audio systems, particularly when consumer-grade hardware like the Mac Mini is serving up the ones and zeroes. The USB REGEN also opens up player separation and adds some tonal mass. Music sounds more alive with the USB REGEN in the chain than without, a conclusion arrived at from applying it to both the Aqua La Voce S2 and the Schiit Audio (multibit) Gungnir.

    Given its higher grade of galvanic isolation, the Chord Hugo TT is a most surprising beneficiary. Remember: this isn’t only about noise making its way from computer to DAC but how hard the USB receiver chip must work to read the incoming data stream.

    On more deluxe servers, the Aurender N100H sees less of an improvement than the Mac Mini and with the Antipodes DX fronting chain of command, the Uptone pre-pendage eliminates more doubt than audible heeby-jeebies.


    Enter again Curious Cables’ Rob Woodland whose USB wire had so far been supplying data to the UpTone device.

    “Hello John,

    Some time back a journo from Time Magazine was quoted as saying “I’ve heard the future of Rock ‘n’ Roll – and it’s Bruce Sprinsteen”.

    Well last night I heard the future of digital audio – and it’s the UpTone Audio REGEN. A complete game-changer, but with two caveats:

    1. Replace the supplied switch mode PSU with a linear supply. I used a $50 Teradak. The switch mode adds noise.

    2. Replace the supplied usb link with the Curious REGEN link.

    The combination of REGEN with Curious usb cable either side is the finest digital I’ve yet experienced. A couple of golden ears were also present. They used phrases such as “dimensional reality” and “intense musical involvement”. Swapping cables lessens the illusion. REGEN/Curious is a match made in heaven.

    Now John, it sounds like I’m beating my own drum here – and I probably am. BUT, I’m also a hard-nosed objectivist, and I call it as I hear it.

    I think you have a REGEN in your arsenal of equipment, and if so I’d be pleased to send you a Curious REGEN link.



    We expect manufacturers to talk up their own offspring but Woodland first gives props to UpTone before big-noting his own. And with my first Curious Cable experiences keeping pace with its manufacturer’s claims, I was reasonably confident that twice the Curiosity might bring further sonic rewards.


    And so it goes…a second, shorter Curious USB cable subbed in for the UpTone-supplied dongle adaptor. The results? An alleviation of some tightness in the upper chest of vocalists and further tension massaged from the joints around which micro-dynamics pivot and swing.

    Listeners with a budget to match their optimisation aspirations shouldn’t hesitate on Curious’ USB REGEN (Inter-)Link but those exercising greater caution with their dollar drop – in this case an additional US$120 – might wish to take advantage of Curious’ 30-day home trial and compare it to a pair of AudioQuest’s JitterBugs. At least, that’s what I’d do if time allowed here…which it does not.

    What has me really spun out is how for the same money as a Resonessence Labs Concero HD, a Bi-Curiously-cabled USB REGEN takes music’s avidity and acoustic mass further north than does the Canadian brick.

    A conclusion that brings forth our fourth and final C: Conversion. Or rather the lack thereof. No S/PDIF hand-off takes place in UpTone land: the REGEN and Curious combo keep tight to the USB signal path.

    UpTone Audio are also threatening their own “crazy new small” linear power supply for Q1 2016 and I rather sense there’s still more to be juiced from the tiny hanger-on-er-rer. In the meantime, consider yours truly a convert already.

    Further information: UpTone Audio | Curious Cables

    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. Just wondering if you would get the same improvements from network streamers like the Auralic Aires or is this specifically aimed at PC use? Assuming power supplies wouldn’t be required.

      • Depends on the device. I’ve not tried it with the Aries. I guess that’s up to readers to suck n see.

    2. The PSU adds noise? Pretty vague.

      If I connect my Regen direct to my motherboard I hear very audible packet noise.

      If I put the Adnaco in the loop it’s gone.

      I just wonder at some folks using multiple regens and cables ad infinitum and multiple custom LPSU. I hope they are starting wit cleaner USB bus than I have. I’m assuming this packet noise can travel on the negative lead which is what it does in my case unless I untether via the fiber-based Adnaco.

    3. John,
      I’ve been using the REGEN fed by a filtered linear power supply and connected with various USB cable solutions, and recently had the REGEN connected to my DAC with the short Curious USB cable. I would agree that REGEN + Curious USB combo does indeed bring all the good stuff that you mention in the article.

      Eventually it will be better understood what these tweaks are bringing to USB audio and they will be incorporated into next-gen DAC’s – but I don’t care to wait around until then. I get to enjoy improved sound today with the REGEN + Curious USB and my existing DAC’s.

    4. Cheers – thanks for adding the video. It really helped me understand the connectivity and context. Next step to try it myself. Great stuff.

    5. John,

      You mention that ‘deluxe servers such as the Aurender N100H sees less of an improvement than the Mac Mini’ with the Uptone Regen. Is this comment made using Curious USB cables on both sides of the Regen and using the linear power supply?

      Brian …

    6. Debating whether to purchase this or the Yellowtec Puc Lite which is much more expensive ($500) and has an AES output. Just received the Curious Cable and have the La Scala. Given that you heard an improvement I probably will purchase a REGEN and the Curious REGEN link.

    7. I’ll be following in your footsteps, trying to regen up a 3-metre Curious leash to see whether the minor loss of focus vs. the 1-metre can be offset or outdone by adding that active inline USB repeater. It’ll be a postscript to my Curious review…

    8. Thanks John,
      I think Computer audiophile did the wyrd. Jitter bug Regen combo. Did you get a chance to try them.. Or am I jumping the gun. ..

      I think the outcome was Regen, Jitter bug.
      All three was a loss of signal integrity and it starts to get into the law of Diminishing returns. Not that bothers the endless audiophile Oligarchs..

      Big fan of DAR so thanks and good luck

      Dave P
      Themidtm off headfi..
      8^ )

      • Hey Dave – nope, as you can probably tell from the piece, spare time is at an all low ’round here.

    9. Thanks for your report. I just purchased the Curious USBs (two cables) to go with my USB Regen and my experience has been similar to your own. There seems to be excellent synergy going on between the Curious and Regen.

    10. Fascinating, this being published on the same day our US postal person is supposed to deliver my Curious USB-Link.

      Hasn’t come here yet, and so nothing to add, other than Mr. Darko has increased my excitement.

    11. John,

      How would the cables improve when paired with the N100H. I am using one now with Kimber USB into PS Audio Directstream DAC.

    12. John,

      I have a similar question to Jeff. In your review you mention that deluxe servers such as the Aurender N100H benefit less with the Regen/Curious combo than a when a Mac Mini.

      So the question is, do you think the Regen with Curious USB cables on both sides would benefit the sound when an Aurender N100H is used as the music player instead of a Mac Mini. Jeff seems to be using a PS Audio DS DAC and I’m using a Devialet as my USB DAC.

      Brian …

    13. Hi.
      I have a question, so does the Regen improve sound also on Hugo TT? By how much? I do not own it, but I have a usb transport (Casea Aquila) which is also galvanically isolated and I am wondering if I will get any improvements with buying a Regen. Thank You 🙂

    14. Hi John,

      Thanks for the many great articles you’ve written – always enjoyable reading. 🙂

      Given that the Curious cable’s external +5V (Pin 1) wire is the most significant departure from traditional designs, I’m left wondering what impact this feature could possibly have when used to feed the USB Regen, which blocks Pin 1 completely, using only Pins 2, 3, and 4 (for data and ground) from the incoming USB cable.

      Disregarding any other benefits of the Curious cable’s design (achieved within the sleeved, 3-wire portion of the cable), the Curious USB Regen Link, placed between the USB Regen and the DAC, therefore has an infinitely better chance of exhibiting Rob Woodland’s primary innovation than would using one of his Curious cables to feed the USB Regen.

      Try cutting the external +5V wire of the upstream Curious cable while listening to a familiar track. If you can hear a difference, I’ll say, “I’m sorry.” 🙂


    15. John,

      I re-read your review on the Uptone Regen before ordering one. I originally thought the Regen came with 1 Curious USB cable and now understand that you must be already be using a Curious USB cable and you suggested for better SQ to order the Curious USB interlink cable for US$120.

      I already have a high-end USB cable (Synergistic Research) that I can use from my Aurender N100H to the Regen. Is there a special sonic quality gained by having Curious USB cables on both sides of the Regen? Or will my Synergistic Cables suffice from the Aurender to the Regan and then use a Curious USB Interlink cable to connect the Regen to my Devialet USB DAC ?

      Brian …

    16. Can you compare with the remedy reclocker using entry level cables?

      The remedy should be the cheaper option for a mac sitting 2 meters from the dac.


    17. Hi John, thanks for your review. It’s always a pleasure reading one of yours.
      Where do you think curious produce more improvement: with the longer cable between pc and regen, or with the shorter link between regen and dac?

    18. We know the external +5V wire of the Curious cable will be blocked at the input of the USB Regen, so there’s obviously something really good happening inside the three-wire, sleeved portion of the Curious, when used between the source and the USB Regen.

      But there are several testimonies from USB Regen owners, in the USB Regen thread at computeraudiophile, which support omission or blocking of the +5V wire (Pin 1) of various USB cables that have been tried. Some are saying that even just taping over the +5V pin at the source connector, is rewarding. Others are paying for custom 3-wire cables that omit the +5V wire altogether.

      And long before the USB Regen or the Curious came along, we’ve seen USB cables where the data wires were sleeved separately from the power wires, no doubt to good effect. Indeed, Rob Woodland’s most obvious innovation with the Curious cable is his segregation of the +5V wire from the the other three within the sleeve.

      Given these testimonies, it seems there’s room for improvement of the Curious cable, because even though the USB Regen ignores the +5V wire at its input, having that wire lying dormant alongside the two data wires within the same sleeve is apparently not a good thing – especially if it’s electrically connected to the source. A growing consensus believes the unused +5V wire is not inert – that it can compromise the sound.

      Is there room for another Regen-specific product in Rob Woodland’s line?

      Combing these strategies with feeding the USB Regen in mind, perhaps the “ideal” cable coming from a source would look like the Curious at first glance, but which has only the data wires within the sleeve (Pins 2 and 3), with the ground wire (Pin 4) running externally, omitting the +5V wire (Pin 1) altogether.

      A quick test of whether or not that dormant +5V wire within the Curious sleeve is affecting the sound, can be conducted by taping over Pin 1 at the USB A connector (at the source):

      An easier test still, would be inserting SBooster’s VBus Isolator between the source and USB cable:


    19. Isnt the W4S Remedy doing the exact same thing as the Regen when doing its reclocking? so why do you only compare it to the Wyrd and the Jitterbug?

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