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ALO Audio ready ‘The Key’ portable USB DAC/headphone amp

  • The super-budget DAC category seems almost unstoppable at the moment. Joining Audioengine, HRT and Audioquest in the sub-$200 portable DAC/headphone amplifier fray is Portland’s ALO Audio. ‘The Key’ is an anodized aluminium USB-key-sized unit complete with end cap to protect the direct-connecting Type A input plug – no USB cable required.

    It’s USB 2.0 compliant and can therefore handle all sample rates up to 384kHz. Resolutions turn up at 16, 24 and 32 bits.

    As is usual with this size of DAC, output comes via a 3.5mm (1/8″) stereo jack; ideal for headphones but you’ll need a 3.5mm-2xRCA cable to hook it into the back of a standard stereo amplifier. Output voltage is a standard 2 volts (at 10 kOhms).


    Further specs:

    • Frequency response: 5-22kHz (+/-1dB) – @ 44.1kHz, 5-150kHz (+/-1dB) – @ 384kHz
    • THD+N: 0.001% @ 1kHz

    The Key is available now in blue, silver, gold and black and sells for US$189.

    Further information: ALO Audio

    John Darko

    Written by John 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. This is great! When you can, please tell us how this unit sounds in comparison to AQ, HRT, Audioengine, Cambridge, etc in this genre. I wonder if Apple and various PCs are going to see this trend and offer a $100 – $150 upgrade rendering the built-in headphone jack the equivalent of one of these thumb-size dacs.

      • I wonder if Apple and various PCs are going to see this trend and offer a $100 – $150 upgrade…
        Mmm; interesting idea. I’d love to see a deluxe iPod with top-notch DAC’s and amps inside, capable of handling the so-called ‘high resolution’ files just to keep the audiophiles on side.

        • Not that I’m particularly fond of speculation but I don’t foresee Apple ever really getting into this sector. Top notch iPod? Astell&Kern and Calyx are already on that case.

    2. I have a very new computer (Lenovo A730 desktop all-in-one). I’m running Windows 8.1 and my computer is so new that it only has USB 3.0 ports. No USB 2.0.

      I’ve already had to return one DAC, the iFi iDSD, because I could not get it to play high resolution files on my machine. As you know, Windows requires a driver for anything above 96 / 24. I know Mac people don’t have this issue.

      I was unable to determine if the issue was that iFi’s driver wasn’t compatible with Windows 8.1, or if perhaps the iFi iDSD did not like being connected to a USB 3.0 port.

      I’m nervous about all of these new DACs, because it’s very difficult to determine if their drivers work with Windows 8.1 and if they will tolerate USB 3.0-only without trying them. I guess I will just have to wait for manufacturers to start stating their Windows 8.1 and USB 3.0 compatibility more clearly. Many manufacturers don’t seem to be addressing these two questions at this time…

    3. Hey David – I understand your pain… I think your probs have more to do with windows 8.1 vs. USB 3.0 – I have an older PC with windows 7 and the iDSD works fine with USB 3.0. On that laptop I have both USB 2.0 and 3.0. I wouldnt get too discouraged about it, and globalize. USB audio is still in its INFANCY, although GREAT strides have been made in the past 3-5 yrs. Ride the wave my friend. Pick the fruits that are low hanging now. For sure it will all progress, quite shortly…

    4. 2 volts (at 10 kOhms).

      Don’t think this will drive a headset nicely, this is a typical line-out

    5. John –

      Thanks. Do you know if it can be hooked up to an iPhone 5 via a USB lightning cable? I see that DAC that draws < 100 ma can do it with proper drivers. Can you get that info confirmed for "the key"?

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