Reviews of Attainable Hi-Fi & Home-Theater Equipment

Reviews of Attainable Hi-Fi & Home-Theater Equipment

Note: for the full suite of measurements from the SoundStage! Audio-Electronics Lab, click this link.

Reviewers' ChoiceI don’t think I’ve ever prejudiced a review as much as this one. It started with an editorial in which I questioned the need for external digital-to-analog converters outside of specific use cases, such as adding digital connectivity to an all-analog setup, or adding support for formats not handled natively by the internal DAC of a beloved piece of gear. Brent Butterworth and I followed that up with a discussion on the SoundStage! Audiophile Podcast, in which we basically concluded that DACs have become a commodity, which is an increasingly common sentiment in the industry. But as I said in my unboxing blog post for iFi Audio’s Zen One Signature, if there’s one DAC that I think has the potential to address all of the relevant use-cases listed above while also being reasonably priced, it’s this one.

iFi Audio

The Zen One Signature decodes PCM at word lengths and sampling rates up to 32-bit/384kHz (not 192kHz, as I mistakenly said in my unboxing post) via USB. It also supports DSD256, decodes MQA, and supports all the relevant Bluetooth codecs, including AAC, aptX Adaptive/HD/LL, LDAC, and LHDC. Its optical and coaxial digital inputs can also handle 32-bit/192kHz PCM (which is, I think, the source of the confusion from my unboxing), as well as MQA.

The DAC employs a Burr-Brown True Native DAC chipset for decoding PCM and DSD, along with a Qualcomm QCC5100 integrated circuit for Bluetooth. Reliance on high-quality muRata, Panasonic OS-CON, TDK C0G, and ELNA Silmic II capacitors and Vishay MELF resistors also points to thoughtful design that’s somewhat incongruous with the Zen One Signature’s modest $349 MSRP (all prices USD).

In addition to its coaxial input/output (RCA), optical in (TosLink), and USB Type-B connection, as well as its sizable Bluetooth antenna, the Zen One Signature features stereo RCA (line level) outputs, as well as a 4.4mm balanced output, which will likely be of most use to someone looking to mate the DAC with iFi Audio’s $299 Zen Can Signature HFM analog headphone amplifier.

iFi Audio

All of this is wrapped up in a sleek chassis that follows the curvilinear design common to all of iFi Audio’s Zen product lines. I think the thing I like most about the design, though, is its reliance on clear visual clues that tell you at a glance, from across the room, what it’s currently doing. The main iFi logo in the center, for example, glows different colors to let you know what format is currently being processed, dependent upon whether you’re relying on one of the physical inputs or connecting via Bluetooth. White means PCM or LHDC; cyan means DSD or LDAC; green means MQA or aptX Adaptive; blue means MQA Studio or bog-standard aptX; and magenta, as I understand it, means that the DAC is either acting as an MQA renderer after an external source has already done the first MQA unfold or, if you’re using Bluetooth, it means you’re getting aptX HD. And if the light is off, that means you’re listening via Bluetooth but with standard SBC instead of any advanced codecs.

To the right of the illuminated logo is a circle that glows yellow to indicate 44.1/48kHz PCM decoding, white if you’re listening to 88.2/96/176.4/192/352.8/384kHz PCM, cyan for DSD64/DSD128, and red for DSD256. That all seems like a lot to remember, but I found I got the hang of it quickly, likely because I don’t subscribe to Tidal, don’t own any MQA files, and rarely listen to DSD (though I did so in the course of testing the Zen One Signature).

iFi Audio

Aside from a power button and an input selector button, there aren’t any controls to worry about, as the Zen One Signature is purely a digital-to-analog converter, with no amplification, no volume control, no EQ, no anything else of that sort—all of which means you’d think there’d be nothing to talk about in terms of setup. But this is me we’re talking about, so of course it wasn’t that simple.

Setting up the iFi Audio Zen One Signature DAC

This is where I would normally walk you through the straightforward process of connecting a product like the Zen One Signature between my PC and the integrated amp currently in my system (in this case, Rotel’s A12MKII, which will be heading back to the manufacturer soon) and perhaps discuss the function of its self-explanatory buttons and such. But I need to confess right from the giddy-up to a mistake in the setup process that turned out to be a happy accident.

Normally, I wouldn’t even consider powering a DAC connected to my hi-fi setup with USB power, partly because my Maingear Vybe PC is the one component in my system not connected to my SurgeX power conditioner, but also because the USB power from my PC is just inherently filthy. Nearly every DAC I’ve ever tried to power via a USB connection to my computer in this setup invariably sounded a little noisy, a little grainy, a little rough.

As such, I would have sworn to you that after running a Monoprice Monolith #33464 USB Type-A-to-USB Type-B cable to the back of the unit (the included USB cable, while nice, is way too short for my setup), I then connected the included power cord to the back of the DAC and plugged it into my SurgeX XR115. I might have gone so far as to pinky swear, so clearly did I remember doing so.

iFi Audio

It wasn’t until a few days later, when I was in the middle of an in-depth listening session, that I looked over at the ottoman where I had placed the packaging for the Zen One Signature and noticed a power brick that looked suspiciously like the one that came in the box. I started to suspect that I might have done an oops. Indeed, a quick check of the back of the unit confirmed that, to my horror, I was running off of dirty USB power.

But here’s the thing: I then plugged in the included power supply and resumed my listening—and I couldn’t hear a bit of difference. So I unplugged the power supply and moved my USB cable from my PC to a cheap powered USB hub plugged into the wall, and I still couldn’t hear any meaningful difference.

What does this mean? To me it indicates that whatever iFi is doing by way of noise suppression has a significant impact on the performance of the unit. So, in complete defiance of my biases, I decided to forgo the power brick and do all my listening to the Zen One Signature powered by USB, mostly to free up an extra power outlet for some testing I’m currently doing for Wirecutter.

Aside from the physical connectivity and installing USB drivers for Windows, there really wasn’t much else to do in terms of setup. The DAC doesn’t have selectable filters, which I think is a consequence of being an MQA decoder, not just a renderer, though don’t quote me on that. Operationally speaking, the Zen One Signature is pretty much set-it-and-forget-it, and my only complaint about it in terms of day-to-day use is that you have to press the front-panel input-selection button to switch between USB and Bluetooth connectivity.

How does the iFi Audio Zen One Signature sound?

I mentioned Bluetooth there, because for my first few days with the Zen One Signature, I relied on it primarily as a reference against which to compare a number of standalone Bluetooth receivers for that aforementioned Wirecutter roundup. I also spent a good bit of time comparing its Bluetooth decoding to that of the Rotel A12MII.

iFi Audio

To be blunt about it, there was more of a difference between the Rotel’s BT reception and that of the iFi than I would have expected, and I don’t think all of that can be attributed to the latter’s more advanced codec support. With tracks like Lyle Lovett’s “She’s Already Made up Her Mind” (Joshua Judges Ruth, 16-bit/44.1kHz FLAC, Curb Records / Qobuz), I could really hear a difference in things like the delicate cymbal crashes, as well as the attack of the acoustic guitars. There was also simply more appreciable sparkle in the higher frequencies, and an accompanying increase in the sense of space, with improved soundstaging and imaging.

Just taken on its own terms, the Bluetooth output of the Zen One Signature is clean and quiet, with none of the operational quirks you sometimes get from the BT built into hi-fi gear these days, such as auto-muting in the absence of a signal or the weird popping that can accompany track changes. Of all the standalone Bluetooth receivers I put it up against, the only ones that sounded nearly as good via analog connections were, unsurprisingly, iFi Audio’s own Zen Blue V2 and Zen Air Blue, although the Audioengine B1 gave it a run for its money when I used its optical output and relied on the DAC built into the Rotel.

Given that this is a SoundStage! site, though, chances are that very few readers will care about the BT functionality of the iFi, so I quickly switched over to its USB input and settled in for some in-depth listening, making frequent comparisons between it and the USB DAC of the A12MKII. I struggled to hear any meaningful differences between the two, but don’t read that as a slight against the Zen One Signature. The A12MKII’s DAC implementation is excellent.

iFi Audio

Of course, the Zen One Signature does have a major advantage over the DAC built into the Rotel—namely, its support for virtually every digital format under the sun. The fact that it supports DSD completely gave me an opportunity to compare the ALAC and DSF versions of David Chesky’s new Graffiti Jazz album (The Audiophile Society AS5), specifically the speaker mixes. (The album comes with separate headphone and speaker mixes, and is available in formats ranging from DSD to PCM from 24/48 up to 24/192.)

Making meaningful comparisons between formats proved more difficult than I expected, given that JRiver Media Center (my playback software of choice for DSD) rendered the ALAC and DSF files at radically different loudness levels. But I did my best to level-match them, at which point there wasn’t enough difference between them to care about or reliably identify blind. But still, it’s nice to be able to access some of the DSD recordings I have kicking around on my music server.

Setting format comparisons aside for a minute and just focusing on the Zen One Signature’s D-to-A conversion with Graffiti Jazz, the only word that comes to mind is “unimpeachable.” With the fifth track from the album, appropriately titled “Graffiti Jazz No. 5 (Speaker Mix),” the Zen One Signature proved itself to be a highly capable DAC from the very first note, delivering the precise attack and decay of Chesky’s virtual instruments with unassailable precision and wonderful dynamics. That moment around the 30-second mark when Chesky uses super-wet reverb as something halfway between an effect and an additional instrument in the mix—filling in the spaces between the keyboard notes and interacting with them but not exactly sitting on equal footing with them—came through beautifully, with wonderful spatial depth and the sort of wall-to-wall-and-eleventy-three-feet-tall soundstage that is crucial if you want to get the full effect of this delightfully weird album and its wild mix.

iFi Audio

I have one last listening session I’d like to dig into, but I know this one is going to be controversial, so go ahead and @ me if you feel the need. I mentioned in my review of the Rotel A12MKII that I’m a huge fan of Lewis Taylor’s work, especially the album Stoned, Pt. I. I also mentioned that online streaming copies of the album were plagued by a weird static pop at the beginning of each track, making the original CD (or an old AIFF rip thereof) my go-to way to listen to the album. But for whatever reason, during the end of my time with the Zen One Signature, I wasn’t in the mood to dig through JRiver’s labyrinthine menus and didn’t have my disc player hooked up, so I decided to pull up the album on Qobuz and just suffer the pops.

While much of Taylor’s catalog was there on Qobuz, Stoned, Pt. I was missing. It was on Spotify, though (which I keep around for mobile listening and its excellent family plan, which lets me share playlists with my wife and daughter). And to my delight, the album has been re-uploaded without the static pops. I can only assume the same process is happening over on Qobuz.

At any rate, given the hostility toward Spotify ’round these parts, I wasn’t planning on including my impressions of the DAC’s performance with the album in this review. But I was so struck by the Zen One Signature’s delivery of “Positively Beautiful” (320 kbps Ogg Vorbis, Slow Reality / Spotify) that I had to include it here. You can only get the full effect of this track’s mix via a device with great channel separation, low noise, and low distortion, given how quietly it starts, how densely but delicately the multitracked vocals are mixed, and how precise the percussion is, not to mention the seemingly chaotic intertwining of funky organ and laser-focused wah-wah guitar riffs.

iFi Audio

Forget the bitrate. Forget the resolution. There’s literally zero you could complain about when it comes to this DAC’s handling of this song via this service. It was rich. It was detailed. It was appropriately dynamic. Imaging specificity was laudable, the soundstage was three-dimensional, and transient response was just spot-freaking-on as far as my ears could hear.

What other DACs in this price range are worth a look?

In terms of I/O and format support, a close rival is Topping’s D50s, an upgraded version of the popular D50. At $249, it’s quite well-equipped, and supports almost all the same formats as the Zen One Signature, with the exception of the fact that its BT input lacks LHDC codec support. The D50s also lacks the iFi’s balanced output.

I haven’t tested the D50s myself, and my only hands-on experience with Topping DACs was with the less-expensive E30. But with that one, I could definitely hear a difference between powering the unit with USB versus plugging it into my SurgeX, whereas I couldn’t hear such a difference with the Zen One Signature. So that’s something to consider, depending on your setup.

Another DAC that I like in roughly this class is Schiit Audio’s Modius at $199. This one does have XLR and RCA outs, and relies on completely separate output stages for its balanced and single-ended outputs, but it lacks support for DSD and doesn’t decode MQA. What’s more, the Schiit Unison USB interface only supports UAC2-compliant sources, and it won’t work with Windows versions before 10 or Mac operating systems prior to OS X 10.7 Lion.

TL;DR: Should you buy the iFi Audio Zen One Signature DAC?

It pains me to type this as much as it likely pains you to read it, but all I can say is that I think I’m going to buy my review sample. And yes, I know that’s the single most hackneyed way any writer can end a review, but the fact of the matter is that I occasionally review all-analog products, and I need a good DAC that can decode any and all meaningful digital formats.

iFi Audio

The Zen One Signature not only does so, but it does it well, in a nice and tidy form factor that’s easy to integrate into my system. If I could change one thing about it, I would add auto source-sensing so I could stream Bluetooth audio from my phone without futzing with the input select button, but that’s probably a big ask at this price point.

iFi Audio makes the bold claim that this is the only DAC you’ll need. And I can’t speak for all my readers, but in my case that ended up being a true story.

. . . Dennis Burger

Note: for the full suite of measurements from the SoundStage! Audio-Electronics Lab, click this link.

Associated Equipment

  • Electronics: Rotel A12MKII integrated amplifier.
  • Speakers: Paradigm Studio 100 v.5.
  • Speaker-level connections: ELAC Sensible speaker cables.
  • Interconnects: Monoprice Monolith #33464 USB Type-A-to-USB Type-B cable.
  • Sources: Maingear Vybe PC; iPhone 12 Pro Max.
  • Power protection: SurgeX XR115 power conditioner.

iFi Audio Zen One Signature Digital-to-Analog Converter
Price: $349.
Warranty: One year, parts and labor.

AMR/iFi Audio USA
105 Professional Pkwy, Ste 1502
Yorktown, VA 23693
Phone: (800) 799-4342