iFi audio ZEN One Signature DAC review

Prolific UK manufacturer iFi audio is back with yet another addition to their stylish, compact “Zen” series of devices for home audio. The all-new $519 iFi audio ZEN One Signature DAC promises to be an affordable and capable digital “hub” for your home listening setup, capable of decoding all major hi-res digital formats while featuring a fully-balanced design. And the kicker? The ZEN One Signature DAC also features hi-res Bluetooth support, with support for all major codecs including LDAC, HWA/LHDC, aptX Adaptive/HD/LL, and AAC. 

Adding a ZEN One Signature DAC sounds like a promising way to make any audio set-up a whole lot “smarter” when it comes to adding digital audio upstream - let’s see what it’s like to live with, and how it sounds. 

ZEN One Signature DAC - what is it?  

The ZEN One Signature DAC is just that - a DAC (or, digital to analogue converter, in case you’re wondering). Unlike some of the other similarly-shaped teardrop products in iFi Audio’s range of “ZEN” products, there’s no headphone amplifier or volume control in this one - it’s a DAC in the purest sense, and iFi Audio thinks it may well be the only one you need. The ZEN One Signature DAC is designed to take digital signals from a source like your Mac/PC, smartphone, TV or gaming console, and decode them into a line-level analogue stereo signal so that your other devices can amplify it into the stuff that your brain recognises as “music”. Oh, and it’ll also happily do the same thing when it comes to video/gaming audio as well. 

Just about every digital device that makes sound already has a “DAC” inside - whether it’s your smartphone, laptop, and even your Bluetooth headphones. The problem is, they often aren’t very good ones. The DAC chips that go into these devices are pumped out by the hundreds of thousands and they’re often fighting for real estate under the hood of your electronic device. As a result, they’re generally not optimised for audio quality and can be susceptible to noise, jitter, and generally have a poor power supply (among other problems). This means the music that comes out can be less lifelike, detailed, and well…musical. A dedicated DAC can yield noticeable improvements in the quality of your listening experience, including a greater degree of clarity and detail, plus a more immersive and layered soundstage.

What makes the ZEN One Signature DAC stand out from other digital devices with a similar compact footprint are three main boasting points:

  1. The ability to decode multiple hi-res digital formats, including DSD up to DSD256; PCM up to 384kHz; and a complete “unfolding” of MQA up to 384kHz. 
  2. A fully-differential balanced architecture, with the balanced output being sent out via a unique single 4.4mm “Pentaconn” connection.
  3. The ability to work as a Bluetooth “Receiver”, compatible with signals up to 96kHz from multiple newer higher-resolution codecs, including LDAC, HWA/LHDC, aptX Adaptive/HD/LL, and AAC. 

Digital power and flexibility  

The ZEN One Signature DAC offers you four different ways to feed it with a digital audio signal. A USB input will be the most commonly-used input for desktop listeners, who will be able to connect to their Mac/PC via the supplied USB 3.0 cable. The optical input makes for easy connection to the digital audio output on most modern TVs and gaming consoles, allowing the ZEN One Signature DAC to act as the digital “bridge” to your amplifier. The coaxial SPDIF connection on the rear of the Zen ONE Signature DAC is an interesting one given that it is a digital output as well as an input. When ‘SPDIF’ is chosen as the input on the front of the device it is able to accept an incoming signal from devices such as a CD player, whereas when the USB or Bluetooth inputs are functioning it will send the incoming signal out to downstream devices - handy if you need to convert a USB or Bluetooth signal into a coaxial one for other digital devices. 

iFi has a long experience using Burr Brown DAC chips in their digital devices and they’ve opted for the The Burr-Brown True Native® “Multibit” integrated circuit for the new ZEN One Signature DAC to allow it to decode a host of files in their native bit-perfect state. A Low-jitter femto clock crystal helps avoid the associated “jitter” or timing errors that can occur when decoding digital files, and a 16 Core 2000MIPS XMOS low-latency microcontroller gives the ZEN ONE Signature DAC up to 4x more processing power. 

You’ll have noticed by now that the ZEN One Signature DAC has a small white (detachable) antenna sticking out of the rear of the device - this is what allows it to reliably receive a stable incoming Bluetooth signal for seamless connection to your Bluetooth source of choice. iFi Audio has chosen to use Qualcomm’s new QCC5100 Bluetooth chip in combination with proprietary circuits to create what they describe as an “audibly superior Bluetooth engine”. It’s not always convenient to have a whole wired computer or CD player nearby, and with higher-resolution Bluetooth codecs like LDAC rapidly bridging the fidelity gap, the addition of wireless connectivity is a huge standout on the little iFi’s resume. 

ZEN One Signature DAC - how might you use it?

If, like most listeners in this day and age, you get your music from a digital source such as a streaming service, via files saved on your device, or even the good old compact disc, then a DAC is going to need to sit at the top of your audio food chain. Your integrated stereo amplifier or headphone amplifier may well have a DAC already built into it. But, if you’ve built a headphone or speaker listening setup around separate analogue components then you’re going to need to partner them with a digital-specific device that’ll be able to handle all the file types, formats, and source devices that you plan on using to play your music with. 

Perhaps you already have an all-analogue integrated amp, such as the Cambridge Audio AXA25 Integrated Amplifier? Or maybe you have an old vintage stereo receiver that you’ve been hanging onto for years that you can’t bear to part with? Adding the ZEN One Signature DAC means that you can breathe new hi-res digital life into your equipment and open up a world of convenience by plugging in your Mac/PC, plugging in your equally-vintage CD player with a coaxial output, or by streaming your newest favourite playlist via Qobuz or Tidal from your phone while you’re cooking. Park the ZEN One Signature DAC between your TV and integrated amplifier, and you’ve got yourself a digital “quarterback” ready to switch between your TV’s audio, a nearby device via USB, and all of your your smartphone’s streaming apps over Bluetooth at the press of a button.  

Headphone listeners often find themselves swapping out and changing around their gear, and so desktop audiophile rigs very often consist of separate, dedicated devices. My self-made OTL tube amplifier is about as “analogue” as a device can get and is wholly dependent on what you park upstream from it. Partnering it with the ZEN One Signature DAC instantly drags it kicking and screaming into the 21st-Century, opening up a host of digital input options that are all available via a single “click” of the input button on its front. 

If you’re painstakingly determined to build a fully-balanced audio chain from end-to-end, then the ZEN One Signature DAC has you covered. You’d expect a balanced DAC to be much larger simply because it’d need to park a pair of dual XLR outputs on the rear, but iFi Audio is very much taking a punt on the fact that Pentaconn 4.4mm is becoming a much more prevalent standard in high-end audio. It’s remarkable that a single, tiny port on the back that’s merely the size of a headphone jack can do the same job as a pair of XLR connections. Naturally, you’re going to need to grab yourself an appropriate adapter depending on how you plan on implementing the ZEN One Signature DAC into your system. 

ZEN One Signature DAC - user experience 

The ZEN One Signature DAC is an extremely compact little device weighing-in at only 485 grams. It’s only 158mm wide and can be easily tucked-away underneath TVs, or stacked on top of other equipment. Its curved, sloping profile gives it a more “interesting” look than your average rectangular black box - it gives you the impression that there’s definitely some clever engineering gone into this diminutive DAC. It’s finished in an attractive dark-blue matte metal case with a black metal brushed finish on the front and rear panels. 

Spinning it around to the back, the ZEN One Signature DAC doesn’t leave any room wasted when it comes to inputs and outputs. It’s powered by an external 5V DC power supply which is connected by a small barrel plug, alongside the screw-on facility for the included Bluetooth antenna. The USB, coaxial and optical inputs are rounded-out by a pair of single-ended RCA analogue outputs plus the single 4.4mm balanced output. 

Switching the device on/off is managed via a front-mounted power switch, alongside an input switching button which lights-up accordingly to tell you whether USB, SPDIF or Bluetooth mode is engaged. The ZEN One Signature DAC has two round backlit “window panels” which each change their colour accordingly to let you know which digital or Bluetooth file type is being received (the larger central window), and what sampling rate it is decoding that file at (the smaller right-hand window). You’re going to need the ZEN One Signature DAC’s instruction manual handy as a reference to remember what colour means what as there are no fewer than eight different colour options for file types, and four colours to represent the sample rate being received.  

A third button on the ZEN One Signature DAC’s right-hand side switches the backlight off on the two display windows if you want to keep things a tad more subtle in a darker room, and a longer (three-second) press engages Bluetooth pairing mode. The ZEN One Signature DAC can remember up to eight separate paired devices, and it was a simple, bug-free experience when I tried pairing it with both my Pixel 6 and MacBook. The ZEN One Signature DAC was recognised by my MacBook and Android systems right away with hooked-up via USB, although iFi explains that PC users will need to download a driver from their website. 

Despite having a laundry-list of digital smarts and seemingly complex capabilities, the ZEN One Signature DAC is extremely simple to use on a daily basis. It really is a simple plug-and-play device once you have it hooked-up to your inputs and amplifier of choice, and it doesn’t get any more complicated than pressing the input switch to change sources between USB, SPDIF and Bluetooth. 

Listening to the ZEN One Signature DAC

Starting off with a 24-bit/176.4kHz hi-res FLAC edition of Stevie Ray Vaughan & Double Trouble’s “Couldn’t Stand the Weather”, the ZEN One Signature DAC proved itself to be more than capable digital partner for downstream Moon 430 HA headphone amplifier and Focal Clear headphones - both of which will let you quickly know if there’s anything sub-par being added to the signal chain. The ZEN One Signature DAC displays the signature warmth and musicality that I’ve come to expect from iFi Audio’s Burr Brown DAC implementation having listened to plenty of the other digital devices in their line-up. The little iFi Audio DAC lends a pleasing, resonant character to SRV’s ridiculously complex guitar licks, and the way it recreates transients and the decay in cymbal strikes is convincingly “analogue” sounding - less capable DACs can falter here. 

The ZEN One Signature DAC strikes a fine balance between offering impressive levels of detail extraction from your music while serving up an extremely-pleasing euphonic tone. It’s not the kind of DAC that gets “in your face” with forthright, force-fed hyper-detail, instead I’d describe it as a little more “snug” in character - it encourages you to lean-back and enjoy a liquid-sounding, fun-filled psychedelic ride through King Gizzard & The Lizard Wizard’s sprawling “Polygondwanaland” rather than sit of the edge of your seat to peer into the innermost workings of the mix, which can get rather hectic. 

The buttery smoothness of the ZEN One Signature DAC is well-suited for a more analytic-sounding analogue stage and can round-out the harsher, drier tones that can dominate some chip-based or Class-D setups. For the same reason, the ZEN One Signature DAC is absolutely wonderful-sounding when paired with my Sennheiser HD600 over an OTL tube amp. Chris Stapleton is arguably one of the best vocalists currently alive (in my humble opinion, of course) and his performance of Metallica’s “Nothing Else Matters” on this setup was eight minutes and fourteen seconds of ethereal-sounding, velvety goodness. 

While seasoned audiophiles will naturally lean towards the ZEN One Signature DAC’s wired inputs and hi-res capabilities, its Bluetooth performance is what sets it apart from other DACs on the market and I can honestly one of its most impressive features. Listening to a 96kHz version of Phoebe Bridger’s take on that same Metallica song via Qobuz, I was hard-pressed to hear any perceivable difference in quality compared to a tethered USB listen a few minutes earlier. You should definitely think of Bluetooth as a “bonus” here, rather than a “compromise” - the addition of it in the ZEN One Signature DAC means that you’ll have far more reasons to jump in and simply enjoy your favourite music, whatever the occasion. 

Final thoughts

Other devices in your audio set-up might come and go, but the ZEN One Signature DAC has been designed to be a future-proof “everything” DAC that can remain in your headphone or stereo set-up long into the future. It’s ready for any conceivable flavour of digital file, and its balanced topology makes it a viable contender for partnering with any number of high-end devices in your audio chain. Add stong Bluetooth performance to the equation along with compatibility with the latest hi-res codecs and you’ll be hard-pressed to want for much more out of your standalone DAC.

The iFi Audio ZEN One Signature DAC packs more into one little case in terms of features and performance than a DAC of this size has any right to - and this simply makes it superb value. 

BluetoothDacsIfi audio