Review of the iFi xDSD
About this Review
This review is of the iFi Audio xDSD DAC. The reviewer has no connection with the iFi, the audio industry, or any vested interest in the product. The DAC used was purchased for personal use at retail on iFi’s Amazon store. $399. Content and opinions in this review are those of the reviewer; however, illustrations come from iFi’s press kit available publicly online at https://media.ifi-audio.com/portfolio/xdsd/ unless they are my obviously personal ones taken in afternoon sun on a flooring square.
This reviewer did not rush into this review, as I procrastinate with everything. When I realized that I was going to eventually spew forth a review, I tried to use the unit with as wide a range of equipment as was available, and with different kinds and sources of music. Equipment used in this review will appear at the end of the review.
Music was streamed from iPhone, iPad, Mac Mini, Windows Laptop with RealTec High Definition Audio Card, and a CHUWI HiPro9 Android 8 phablet. Music included some MP3 at 320bps, FLAC and AAC files at various resolutions, TIDAL/ROON high-fidelity and MQA streaming. I’ve included near the end of the review some details about specific albums and tracks, but as my experience was consistent, I did not overdo it. Besides, when I write too long, it can set off my bs detector.
Physical Appearance and Controls
The unit measures 3.75 inches deep by 2.5 inches wide, and .75 inches thick. Yes, I’m an American. For those of you in the rest of the world, it’s 95 x 67 x 19. So, it’s very portable and you will get your grubby fingers all over it. Speaking of which, (ahem) several persons have noted that the finish is a fingerprint magnet. It is. And as they famously said on Seinfeld, “Not that there’s anything wrong with that”. For me, fingerprints merely add character, humanizing that electronic kind of digital with images of my own personal digits.
The xDSD shares a form factor with several other iFi products. It has a very solid feel, nicely done in aluminum. The box contains a few needed wires, a 3.5mm conversion tip for TOSLINK, and a velveteen carrying pouch. It also comes with a USB cable and some conversion tips. There is a meticulously printed manual on a card, resplendent in 5-point type that shows great clarity when viewed with a jeweler’s loupe. Fortunately, the iFi website contains a PDF version with convenient enlargeable type for my tired old eyes.
The business end of the xDSD is dominated by a multi-use wheel, which is an analog volume control, on-off switch, and indicator of volume level or Bluetooth vs Wired function. A rubber button underneath the settings/Bluetooth marking will, depending on when you press it, cycle the analog crossfeed (3D+) or modest 3db bass emphasis (XBass+), the usual functions, or during startup, can force Bluetooth pairing.
To the left of the volume wheel are multi-color indicators for input and sampling rate of music. In order to understand these LEDs, you will need to read the documentation, which comes on a folded cardboard guide in the box. If you are over the age of 16, or don’t have a magnifier handy, the manual is also available online in PDF format, where you may scale the text into legibility.
And of course, there is the output jack. While this will take standard 3.5mm stereo plugs found on most any headphone, it is actually a TRRS jack, capable of “S-Balanced”, or true dual-mono mode, in which the left and right stereo sides are completely separate. Unfortunately, neither the documentation nor the iFi website will tell you the actual configuration of the cable and plug needed to use this. Fortunately iFi’s customer response to support inquiries is pretty good, and I was able to get a response from Alix at iFi that the pinout for the TRRS is T (L+) R (R+) R (L-) S (R-) so that Hamad at Amplifier Surgery could build me the required custom cable to connect Sennheiser HD-580, HD-600 or HD-650s in dual-mono mode. The exercise is worth it.
The TRRS Dual-Mono cable from Amplifier Surgery. I can only use this with the xDSD and Sennheiser headphones, but it is worth it. There is an AUDIBLE difference when using Dual Mono mode. I say this because there is NOT an audible difference when switching the cheaper cable from the HD-580 with the better one from the HD-6XX. But using Dual-Mono (or S-Balanced as it may be confusingly called) does result in clearer separation, better soundstage, and a slightly quieter background. While I have not attempted to measure this – no equipment but my ears, the difference as immediately noticeable, and clearly preferable.
The ass end of the xDSD is where you put both the electricity and your music in. Alert readers will note a filter. The documentation says, “Different digital filters are available for PCM & DSD. For listening enjoyment, we recommend the transient optimized minimum phase ‘Listen’ filter but feel free to choose the frequency response optimized ‘Measure’ filter.” I haven’t the faintest idea what they’re talking about and keep it on Listen. I can’t hear any difference, but I have only a limited selection of PCM and DSD source material.
The USB is happy to accept a digital USB connection. A USB cable comes in the box, which is good, because some premium USB connectors have oversize plastic crap around the connectors and may not fit. Most reasonably priced cables fit just fine. I did not try the TOSLINK connection, as getting to my only TOSLINK digital audio involves climbing into the rat’s nest of cables in my home-entertainment cabinet.
A micro-USB connector is available to power this unit. It has a 2200 MAH battery inside, which I have never drained completely. It’s adequate to power some relatively thirsty headphones for about 8 hours. You may, of course, power the unit at the same time it’s playing. I could not hear any deterioration of sound while doing this, although I tried to A/B a wall-wart with a Mophie battery backup.
One of the features of the xDSD is its ability to connect via Bluetooth. The specifications say that it will also connect using the higher-fidelity aptX and AAC protocols. After fumbling around a bit and finally reviewing the instructions, I was able to get the DAC to reliably pair with Apple devices and with an Android tablet. In the connected devices it shows iFi xDSD aptX, but after contacting iFi, I find that this is just what they named the device, and it actually is connecting using AAC on iPhone. They tell me that this information will make it into their online knowledge base, eventually.
(Note to editor, just casually left in the review – yes, I know that iOS does not support aptX and that MacOS does. However, I was trying to point out that the device identification which was determined by iFi firmware was aptX centric. They probably named it without thinking about how odd it would look on AAC. It could have simply been called “iFi xDSD”. It reminds me of the Monty Python skit where the customer wants his shirt cleaned in an hour. “That’ll be 3 days.” “But the sign outside says ‘1 Hour Cleaners’” “That’s just the name of the shop, it’ll be 3 days.”)
It is very convenient to use Bluetooth, especially with mobile devices, and I never felt like I was sacrificing much in quality during casual use. However, the best quality is obtained with a wired connection, as Bluetooth has inherent bandwidth and lossy quality.
The form factor and battery make it truly portable, although when using it in wired mode with an iOS device, it requires a Camera card from the lightning output, as does any other external DAC. With the Dragonfly, this is still quite compact, with the xDSD, you must deal with a longer cable (see photo comparison elsewhere in this review). I was able to use a “To Go” cable for Android connection directly.
Cracking Open the Case
I wanted to see what was inside this mysterious box, but I couldn’t find my technical screwdrivers to fit the tiny screws. However, where there’s a will, there’s a way:
Once the case is open, one finds the PC board with all the goodies. Note the sticker over the chip that provides Bluetooth/AAC/aptX so that you can’t see the manufacturer.
The Burr-Brown chip is toward the bottom, about 2/3 of the way to the right. It has a state of Texas printed on it next to the BB logo. That’s where the DAC stuff happens.
Here’s a size comparison with the Dragonfly Black. Note the Dragonfly is connected to a Jitterbug. Both DACS are small enough to be easily mobile, but the xDSD can’t be called tiny. It does have the advantage of battery power and will not drain an iPhone. It also has power to drive inefficient headphones well. If I use the Dragonfly on an iPhone with Apple Camera Connection Kit version 2, it drains the battery. It’s fine with the Camera Kit 3 (AKA Apple Lightning to USB Adapter) and an outside power source, but it gets clumsy. The Dragonfly is fine with any IEM I’ve tried, and with my Grados. It begins to struggle with the Sennheiser HD-580 and HD-6xx, far better than just plugging into iPhone, but not really getting LOUD. The xDSD on the other hand, offers not only Bluetooth connection, but enough power to drive the Sennheisers and my HifiMan HE-560 to serious levels.
The Road to DACdom.
In some ways, I find it odd to write a review of a DAC. It took me a fairly long time to learn about DACs. Eventually, I found that I probably had more of them than I realized. When I first got a CD player, it was a portable, and I didn’t care for it too much. Then I had a NAD that was pretty good in my stereo chain. I picked up a CD changer by SONY that was supposed to be an upgrade, but the sound always left me wanting something. I didn’t know it was a DAC.
I replaced the SONY with a Rotel, and it sounded better. A friend told me the Rotel had a Burr Brown DAC, and they were also known very good quality with op-amps (Burr-Brown is presently owned by Texas Instruments (TI) one of the major players in the analog to digital world). Over the years, I’ve had a chance to make a few comparisons. I have a TEAC DAC, and a Dragonfly Black DAC. The TEAC I own also has a Burr-Brown chip while the Dragonfly has an ESS Sabre. Perhaps I’m suggestible, but I have listened to several other DACs and the Sabre seems very precise, but I find myself tiring more quickly.
I find that I experience the least ear fatigue with analog chains, but good mastering and a good quality DAC can also provide serious listening pleasure. In truth, I don’t think that there is much a non-engineer can say about the relative merits of particular chips. Other features of DAC design are much more important. Controls, battery life, lack of noise in the rest of the circuitry. Here, the xDSD proves to be more functional and better equipped to deal with the world than either of my other DACs.
MUSIC and How I Listen
I could go on for a while about the dry specs. But I think it’s time to talk a little bit about the subjective experience. First, I didn’t take a bunch of measurements. You can find that in their tech notes. I applied my Mark I human old ears and listened.
My tastes in music run from acoustic to zydeco. Except for country music product. I used to go to a fair amount of live music, and still do when I get the opportunity.
Notes on the Listening Chain
My critical listening is mostly done on digital sources coming from a 2014 Mac Mini running TIDAL and Roon. I tend to listen via Roon. If the source comes from my Windows laptop (A Sager 9150) then it is usually TIDAL without Roon. The digital output is then run through a DAC; presently I use either a Dragonfly Black with Jitterbug or the xDSD. NOTE THAT THE Jitterbug CANNOT FIT directly into the xDSD USB port – the surround is too large. I have not bothered using extenders.
Most often, the output of the DAC goes into my Mjolnir-Audio modified STAX SRM-T1S tube amp, and I listen with a vintage SR5n standard-bias STAX earspeaker.
If I don’t connect the STAX setup, then I plug normal headphones into the DAC. In doing this review, I have used Grado SE-60s, HiFiMan HE-560s, and Sennheiser HD-580s and Sennheiser Massdrop HD-6XX headphones.
When not at the Mac, I have used the xDSD from an iPhone 6+, iPad Air, iPad Pro, and CHUWI Hi-Pro9 Android sources, both in wired and Bluetooth configurations. With these more portable sources, I also tried some IEMs, although I’m not much of an IEM guy. I guess the best I have are 1More Triple Drivers, but I also have some middle of the line Klipsch and vSonic IEMS that I tried.
All I can say about using the xDSD with IEMS is that it drives them easily and is otherwise not remarkable, probably because my IEMS are not remarkable. I would very much suspect that those who use high-end IEMS would find, as I do with better headphones, that the xDSD gets out of the way of the music. With IEMs I found that the “3D+” crossfeed setting was at least as good as the similar setting I used to turn on when I used the Headroom Airhead amp back in the day. It does what it’s advertised to do – expand the sound stage, and it does so without causing fatigue or annoyance.
Above you will see the headphones I used most frequently in conducting this review. Note that the Stax must go into a headphone amplifier, which gave me the opportunity to test the line-out function of the xDSD. While it’s certainly easy to use the standard settings and adjust the volume to suit the input of an external headphone amp, there is a potential danger of giving too much output. The line-out function both simplifies the output path and provides a wholly adequate output level. I should note that the sonics of the analog section of the xDSD are so good that I was not able to detect any difference in sound using line-out vs just plugging in to the headphone jack.
As some readers of my other postings know, I’m skeptical, cranky, and dismissive of reviews talking about how good cables (patch cords) are, and of cryogenic malarkey. So, it’s with some amusement that I’m writing about the sound of something that really shouldn’t be remarkable.
First, there are things that are not questionable. The xDSD does a fine job at converting bits representing music into electrical waveforms that adequately drive a wide range of headphones. This is important. Before we had DACs, we had headphone amplifiers, and it’s really nice to have a unit that I can plug in some thirsty planar-magnetics, and not have to look for ANOTHER amplifier so I can hear the sound.
The amplification section is quiet and precise. I never heard any noise from analog controls. The volume wheel is smooth and quiet. Deep bass is properly rendered. I looked for digital versions of albums I know, and the recording of the 1812 Overture I tried had all the punch I have ever heard from headphones, the HD-580 and the HiFiman HE-560. Including the cannon. I listened to Bach on church organs and the low notes were rendered at least as well as they are when I play though an analog chain and use my non-portable TEAC DAC or an integrated amp headphone output.
I have said elsewhere that I like what I think of as the Burr-Brown smoothness. It’s hard to put this into words, but I find that when I listen to say the Sabre DAC powered Dragonfly, and one or two other examples, that I feel ear fatigue. More precisely, I think it’s in the 1000-3000 hz level that this comes out. My cheap Grados are already just a tad present in the treble, and after 15 minutes or so, I have to take them off, even if I’m enjoying the music. This doesn’t seem to happen with the xDSD (it happens fast with the poorly recorded cymbals on Blind Faith in an analog chain, I think it’s a harmonic of the higher frequency that drives me crazy). I find I can listen to the same content (Rolling Stones “Satanic Majesties’ Request) for longer without fatigue using the xDSD. In fact, without fatigue. With the Grados. And then the HiFiman. And then the STAX…
Then there are the things that are challengeable. What does quality sound like? What is soundstage? One of the albums I like to use to define soundstage is Cannonball Adderly’s “Live at the Club”. This album famously or infamously purports to be a live album recorded at a small music bar venue. It is not. It is an early masterpiece of studio fakery. Which does not keep it from being great music and a great recording. When listening to this album on proper loudspeakers, you will feel you are in a mid-sized bar, with a few tables in front of you. There is occasional noise of a glass with ice, or people talking.
Listening with the STAX, particularly when using the 3D+ setting, I get a similar soundstage. I generally don’t like the 3D+ crossfeed, but it is better when used on live albums or ones that purport to be live like the Adderly. I don’t get as much of this soundstage with IEMs, although the 3D+ again helps. I find that I get more “ambient” sound resolution with the xDSD than either with another external DAC, or than when I listen directly to something from the Mac Audio out port.
I’ve been critical on occasion of digital source compared to analog. While the xDSD is hardly the only DAC that is good enough, I find that with high-resolution files, or with MQA streaming that I can no longer tell that I’m not listening to an analog chain. And I get to the point where the DAC is relegated to one of the least significant disturbances in the musical enjoyment experience. It’s not live – but it’s sure not objectionable. And sometimes faint praise is high praise indeed.
Some Music Already
David Bowie – Glastonbury 2000
A live album, recently released on TIDAL with MQA. I did an A/B of the xDSD vs my Dragonfly Black with Jitterbug. Both can resolve the full stream. I noticed more depth of stage with the xDSD, and using the crossfeed button on the xDSD, I very much got the feeling of being in the hall. The recording is very live, with all that implies. I found that the slight (3DB) bass boost was also of benefit in this recording. I don’t often use any modifications.
Schubert Die Nacht by Anja Lechner/Pablo Marquez
I appreciate the smoothness of the Burr-Brown chips here – or at least I imagine that I do. It’s difficult to tell what part the DAC contributes. It does not get in the way of the music. I’m talking about this piece because it is classical guitar, cello and piano. I have a lot of experience in listening to live classical guitar and piano; I know what to listen for. The recording is very good, and the MQA chain on TIDAL/Roon assures me that I’m getting what the studio engineers desired. I hear the faint scraping of the bow on the strings, the occasional finger sounds on the guitar, the attack of a thumbnail on the strings. When I close my eyes, I wish that the microphone had been a bit better positioned by the guitar. There is something that gives away the recording – I think it’s got all of the string and body resonance, but de-emphasized the sounds of fingers on the strings. In live classical, this always sounds more prominent than expected. When I stop trying to analyze, this music is lovely.
Oh! Tapping on the guitar body was just right.
Black Marble & Sweet Fire Al Gromer Khan & Kai Taschner
This album is one of my favorites, and I know it well. I’m not streaming, but playing an MP3 44.1khz 24 bit, 2channel 279 kbps, residing on the Mac Mini hard drive, playing through Roon. I’m comparing it coming directly from the Mini headphone output into the STAX SRM-T1S with output through the Mini’s USB port into the xDSD DAC. The album has well mic’d Tablas, Sitar, kalimba voice, electronic and western percussion. Released in 1996. blends Indian, Northern African, and Western music.
Listening to track 4, Prayer for X. This track features kalimba and electronic background, with a male voice praying. The MP3 out from the Mini is nice enough, it’s a beautiful track, but it has a very recorded sound. Switching to the xDSD, the kalimba is more live and immediate, and the work of fingers plucking the tones is noted. The voice also is more real, and you can hear details of timbre and articulation that are not apparent in the direct output chain. Finally, although the soundstage is improved from the Mini-direct, toggling the 3D+ expands the soundstage and enhances the track’s dreamy effect.
Boot and Paisley is a quiet percussion tour de force, and the xDSD reveals detail and precision. I think we can attribute this to the DAC alone in this chain, because the STAX amp is handling the power to the headphones; it’s not an artifact of having a more capable amp. I’m not running either the Mac output or the xDSD anywhere near the limits. The piano low notes sound very good, almost like the full-size upright downstairs – a detail that I have previously missed on this album.
Flim and the BB’s, New Pants (Songstress track 8, ALAC, 44.1khz Lossless)
Well recorded jazz. I can hear everything. Very metallic cymbals, brushes on drum. Resonance of snare, The reediness of the woodwinds. While Songstress is not the critics favorite cuts, I like its laid-back feel, and enjoy the interplay of the musicians. My conclusion about the xDSD? I forgot it and listened to the music. The next track’s opening – a brash alert shocked me into typing again.
My audio budget is such that I’m careful with what I buy, and I will either get rid of something that is not up to snuff, or I’ll keep it a long time. The Dragonfly DAC will always have a place in my most portable chain, but the xDSD has become my go-to DAC. While learning the controls was a bit fiddly, it does everything I ask, and it does it very well. Yes, I like tubes, but I don’t insist on them in everything, and the Burr-Brown smoothness makes it so I don’t miss tubes when I use this bit of equipment. I don’t give star ratings, or silly percentages on a scale. What I can say is that I got a very good value for my dollar with this piece of equipment. It’s good enough that I don’t covet another DAC. It makes my headphones sound better, and that’s all I can ask.
There are some things that we will always enjoy or never forget. The THWACK sound of an earned game that you just racked up on a classic pinball machine. Your first burnout in your car, or when you finally learned how to do a 4-wheel drift. The time when you bid a grand slam and made it, or executed a progressive double squeeze (that’s in the card game bridge – shame on those of you with minds in the gutter).
So this is what I recommend you try casually listening to your xDSD. Settle back in an easy chair. Put on some big, comfy full-range cans. Stream Radio Paradise, an eclectic FLAC free online service. Pick up a good book, or magazine. Sooner or later it will happen. Radio Paradise will play something that can’t be ignored. Time to smile, turn up the volume to an entirely satisfactory level (Even with Planar-Magnetics) and be carried away. Because you can.