in , ,

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

    Written by John

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

    Darko.Audio is a member of EISA.

    Follow John on YouTube or Instagram

    OPPO Digital’s BDP-105D: an HDMI DAC for the Apple TV

    At last! Apple Music comes to Android devices