My iFi iDSD has made up the centrepiece of my desktop set-up for the last 3 years. Since then I’ve tried numerous DACs and amps – but still the iDSD remains. More recently its coupled with an iUSB (for clean power input), a Gemini cable (to separate signal from power), an iTube (my my LSR 305’s), and it sits nicely on an iRack. Yep – I’ve become a bit of an iFi fan. Every part I’ve just mentioned is owned by me – no review samples.
My review today is the iFi xDSD – a portable DAC/amp in one, only this time we have a Bluetooth connection (so you can go source > Bluetooth> xDSD and have your headphones plugged into the xDSD). Its a solution not unlike FiiO’s Q5 (which I reviewed recently). So why is a device like this an important step in the evolution of HQ portable audio? For me its simply because I always have my smart-phone with me, and it has a lot of my audio library on it. Its interface is fast and well organised. I can stream, I can add apps. Its issue is that its not optimised for audio, and the hardware (while decent) is not audio focused. The perfect marriage of devices for me (rather than carrying another DAP) is to simply lever the UI, software interface and connectivity of my smart-phone and output that through a high quality portable device. And rather than having to carry a stack, be able to look at simpler wireless options.
So lets take an in-depth look at the iFi xDSD, see how it performs, and compare it to FiiO’s Q5 along the way.
iFi Audio is a subsidiary of well known high-end audio product manufacturer Abbingdon Music Research (AMR). AMR is one of the UK’s largest manufacturer of high-end audio systems (founded in 2000). In 2012, AMR introduced iFi as a subsidiary company with the aim of bringing high-end audio to a more mainstream audio audience. By levering trickle down technology from their parent company, iFi have developed a series or audio family product lines (Pro, Retro, Micro, Nano and now the X series) which feature a full range of DACs, amplifiers, power purifiers, cables, and other audio related devices. They have been actively involved in on-line audio communities to grow their brand, and in my own personal experience their support network is also extremely good.
The one thing I’ve noticed with iFi as I’ve used their products is their passion for sound, and their ability to create great sounding products at an affordable price point.
The xDSD DAC/amp that I’m reviewing today was provided to me as part of a review tour. There is no incentive to write the review (other than getting to listen to the product), and at then end of my period with the xDSD (7 days) it is sent to the next participant in the tour. The retail price at time of review is ~ USD 399.
If you haven’t read any of my reviews, I suggest starting here, as it will give you an insight into my known preferences and bias.
For the purposes of this review – I used the iFi xDSD primarily with my iPhone SE, FiiO X7ii, X5iii, and as a DAC/amp with my PC, but also with a lot of other DAPs just to check compatibility (Bluetooth or coax only with the Android devices). I tested with a selection of different earphones (both IEMs and full sized),
In the time I have spent with the xDSD, I have noticed no change to the overall sonic presentation (burn-in). This is a purely subjective review – my gear, my ears, and my experience. Please take it all with a grain of salt – especially if it does not match your own experience.
The xDSD arrived in a 90 x 205 x 47mm retail outer retail sleeve (over internal box and lid). The sleeve is white with a picture of the xDSD on the front, and features and specifications around the sides and rear. Opening the box reveals an inner box with foam insert which holds the xDSD, and to the side there is another compartment with the accessories. The total accessory package with this unit included:
- The xDSD DAC/AMP
- Velvet carrying pouch
- Cable : USB A (male and female connectors)
- Cable :USB B (female socket) to USB A (female socket)
- Adaptor : USB A (male connector) to USB B (female socket)
- Toslink optical adaptor to 3.5mm jack
- “3M type” dual lock tape for attaching xDSD to source device
Note that someone earlier in the tour had used most of this leaving only a sliver.
THE TECHNICAL SPECIFICATIONS
I’ve included the relevant xDSD specs + (where known) comparison to the FiiO Q5
|HQ Blue-tooth DAC and Amp
|HQ Blue-tooth DAC and Amp
|95 x 66 x 19mm
|124 x 64 x 16mm
|Burr Brown DSD173
|AK4490EN x 2
|Output Power 16 ohm
|230mW SE / 470mW Bal. (THD+N <1%)
|Output Power 32 ohm
|160mW SE / 440mW Bal. (THD+N <1%)
|Output Power 50 ohm
|270 mW (3.7V)
|Output Power 300 ohm
|48 mW (3.8V)
|24mW SE / 93mW Bal. (THD+N <1%)
|<0.001% (1 kHz/32ohm)
|Peak Output Voltage SE / BAL
|>2.1V RMS SE / >3.7V RMS Bal.
|>73 dB SE / >97 dB Line-out / 99 dB Bal.
|Output Impedance (32 ohm loaded)
|<1.0 ohm (load not stated)
|<1.4 ohm SE, <2 ohm Bal.
|Battery Performance / Recharge
|6-10 hours use (varies on input/output), <3.5 hours recharge
|8-10 hours use (varies on input/output), 3.5 hours recharge
|aptX, AAC, SBC
|aptX, AAC, SBC
|Sample Rate Support – Up To:
|Up to PCM 768 kHz / DSD512 (USB)
Up to 192/24 (Coax & Optical)
|Up to PCM 384/32 (USB)
Up to 192/24 Coax / 96/24 Optical
|DSD Support (USB In)
|DSD64 / 128 / 256 / 512
|DSD64 / 128 / 256
The xDSD is a lot smaller and a lot lighter than I expected. It’s about the same width and only marginally higher than the Q5, but a whopping 3cm shorter in length and almost 70g lighter. One would be forgiven (especially after handling the Q5) to think that the wavy body of the xDSD is a high tensile polycarbonate. But in reality it is a light-weight magnesium alloy.
The xDSD has 3 distinct sections. The main body and cap are magnesium alloy, while the lower section is a black polycarbonate (presumably to allow transmission of Bluetooth). The casing is a wavy or ridged design which feels comfortable in hand, but the glossy surface is a real fingerprint magnet. For stacking, iFi includes an adhesive product which works very much like 3M dual-lock – and this should allow stacking quite easily with most devices. I’d show this in the photos but unfortunately others on the tour must have thought it was a good idea to use practically all of it up (and yes this is a dig at them) – so I would suggest checking other reviewers if you need a closer look.
The front (or top) cap is dominated by the central volume control knob – which has an inner LED which changes colour depending on the volume and the functionality active at the time. In the centre of this is the iFi logo – and small “nitpick” from me. Ifi – it would be nice if the logo did not move when the volume knob is rotated. In my experience some audiophiles can tend to be a little OCD – so a static logo would have looked aesthetically better. Anyway – the central knob or pot also doubles as an on/off and also a mute switch.
To the left of the pot is the 3.5mm headphone out jack – which has iFi’s S-Balanced technology (I’ll discuss this in a little more detail later in the review), but essentially you can use balanced headphones or single ended, and it will know which is plugged and compensate accordingly. Next to this is an LED showing which input is in use, and also the output sample rate. To the right of the pot is the 3D / XBass LED indicators, and next to that is the settings button which is used for switching the 3D / XBass, setting the line-out mode, and also Bluetooth pairing.
At the rear of the xDSD is the S/PDIF port for coaxial or optical input. Next to this is the USB audio input (type A male connector). Unfortunately There are no USB OTG cables included (either lightning or micro USB) requiring purchase of separate suitable cables. Next to this is a digital filter switch which according to iFi offers a transient optimised minimum phase option (listen) or the frequency response optimised filter (measure). I’ve tested both with a variety of music, and I’m afraid the change is far to subtle for me to notice any real difference. Finally at the far right is a micro USB port solely for charging the xDSD. A charging cable is not included (which I personally find quite strange).
On the bottom of the device are 4 rubber feet (for desktop use).
All in all, the build quality seems pretty solid, although some of the finer points I normally expect from iFi are missing. The rubber bottom cap does not squarely align with the magnesium alloy body creating a slight ridge which is very unlike any of their other products I own. Also the audio jacks may fit well, but they are not exactly firm, and a gentle tug is enough to dislodge the 3.5mm main port. The Q5 is definitely more reassuringly tight. When I was using the xDSD portably during the week, I lost connection a couple of times when my headphone cable was bumped out of the socket.
INPUTS / OUPUTS
Like the FiiO Q5, iFi have really given us the whole 9 yards as far as inputs go, and included are USB, COAX, Optical, and Bluetooth. The only thing missing so far has been analog line-in. I’ve been able to check all of the available inputs, and so far they have worked flawlessly. With my iPhone SE, I simply used aac256 for starters, and then transferred a DSD album via the FiiO app, and via USB it successfully natively played (the DSD indicator LED lit up with the correct colour). I checked coax via the coax out from the X7ii, and once again flawless transmission (and automatic detection and switching by the xDSD).
Unfortunately the one thing I could not test was USB out from any of my Android devices to USB in on the x-DSD. I actually have a couple of cables which could have possibly worked – but neither terminated ina USB-A female. Why iFi uses this method of connection is a little beyond me. Because it is a slightly unusual connection method, it would have been nice to have a USB OTG / output cable included.
USE AS A DAC
My first check was to see if the xDSD could use Windows 10’s basic drivers and be recognised as a DAC without further installation. For this I used my work laptop (64bit Surface Pro running Win10). I have some music on the lap-top, but our Company locks down the OS so we can’t install anything like programmes or DAC drivers. I checked the control panel, and the Windows Sound Mixer had the xDSD recognised and capable of playing up to 32/384. Next was firing up Groove music and queuing an album, and then ….. beautiful music. Two thumbs up iFi.
Next onto my home PC. This one already has the iDSD universal driver set installed, so the xDSD was instantly recognised, and I soon had JRiver running and the xDSD playing native DSD. I quickly ran through my test suite of formats and it does indeed play everything I threw at at it (including ogg, APE, AIFF, WAV, FLAC and ALAC).
Booting out of Windows, my next step was to connect to my main OS (Debian Linux). Again the xDSD was recognised. I ran my purchased installation of Jriver Media Centre for Linux, and played some native DSD. Again – easy recognition, and again the test suite of formats ran easily.
Finally my iOS devices(my iPhone SE and iPad mini). Once again no issues with either, and using the FiiO music app, I can successfully play hi-res including DSD.
I can honestly say not a single hitch. This is ease of use the way its meant to be. Well done iFi – really well done.
Getting into Bluetooth mode was simply a matter of switching the device off, and then keeping the power button depressed for a few extra seconds until the blue light was engaged. Pairing was easy (when it works), with both the i-devices or Android (X7ii / X5ii). Range was very good out to 10m and beyond, and for the most part has been pretty stable. There has just been the odd time I’ve had minor drop-outs and a little static (pops and crackles). These have not been prevalent though, and perhaps simply a sign that the Bluetooth driver may need a little bit of work. All in all though the Bluetooth performance is pretty good and I often use it for walking and especially around the house. The one issue I have is with my iPhone – I’ll go into it down the page a little (see “issues”).
The xDSD supports SBC, AAC and aptX codecs. From what I understand, iFi’s implementation of Bluetooth is not using the on-chip codec, and instead pushing the digital stream to the high quality Burr-Brown DAC. And like the FiiO Q5, this means very good quality audio. So good in fact that I can’t tell wired from wireless. To me aac256 is transparent (I have tested myself many times) and while I’ll use FLAC on my home system – I’m perfectly fine with my lossy aac files – especially for portable use. Between the xDSD and the Q5, I think Bluetooth audio has finally “come of age”.
iFi advertises 6-10 hours life for DAC/amp use dependent on the input source, and unfortunately I simply haven’t had the time to test this fully in the last week (between travelling and using the device). If you’re using USB out, then unfortunately this is the lower end of the scale with ~6 hours, Bluetooth is 8 and S/PDIF is around 10 hours. The 8 hours for Bluetooth feels about right and I’ve easily been getting a full day at work – and for me personally this represents reasonable performance. With a 5V 2.1a charger, full charge (from practically empty) is easily achieved in around 3 hours.
POWER / NOISE / HEAT
The power output on the xDSD is genuinely surprising. I saw no true balanced output and was concerned that it was mainly going to be a device for portable headphones and IEMs. I love using my Q5 with my HD800S around the house – and was hoping the xDSD could possibly mirror that performance.
My concerns were unjustified. The xDSD uses what iFi calls a CyberDrive battery and amplifier system. Don’t be fooled by the small size either – the xDSD is both able to handle IEMs with finesse and an impressively low noise floor, then without a hitch switch to an HD600 or HD800S and put 48mW into those loads (easily able to drive them to listening levels of ~100dB). And both the HD600 and HD800S sounded well driven too – no obvious signs of being under powered.
As far as heat goes, the xDSD has only been very slightly warm during a long listening session, but generally I’ve found the ambient heat dissipation to be excellent. So good in fact that I wouldn’t even call it lukewarm.
FILTER / XBASS / 3D
The digital filter is controlled by the rear listen / measure switch. The two modes are transient optimised minimum phase option (listen) or the frequency response optimised filter (measure). As I alluded to above, I tried the switches with a lot of different music – especially jazz (with a lot of cymbal action). I’m certain that it is making a slight change, and people with better hearing than I will be able to set this to their preference. The change is incredibly subtle though, and I really can’t tell a difference.
The XBass is a different matter though, and while subtle with most music, any tracks having a decent amount of sub-bass (rumble) will definitely notice the boost. It starts very small (1dB at about 100Hz), and by the time you get to 20Hz there is a nicely linear rise of about 7dB.
The 3D matrix is another interesting switch. When engaged, there is a very gentle widening of the stage. The interesting thing is there is absolutely no change to measured frequency response (on my rig), yet the change is easily audible. I’m not sure how iFi has achieved this (a slight change of phase maybe). The really nice thing with the 3D switch is that iFi haven’t over-done it, and for me its a really nice addition to be able to subtly tweak those intimate headphones or that intimate recording – and with a push of a button get a little more spacious presentation.
Before we get to the sound and comparisons, I need to bring to light a couple of niggles (one of which has been really annoying). Both are related to Bluetooth. The first I’ve mentioned, and its the occasional drop-out from both Android and iOS (experienced as clicks and sometimes 1/2 second pauses). In comparison to the Q5 – the xDSD Bluetooth just seems slightly less stable (even though it has very good range).
The real issue is with my iPhone SE. I’ll connect – the iPhone recognises the xDSD, the headphone icon lights up on the iPhone tool bar, and shows in the output. But when I go to play – no sound. Its definitely playing too – everything looks 100% good. Just no sound. If I connect the Q5 – instant sound. I know its not the iPhone. And it doesn’t happen all the time either. Sometimes the iPhone will play without a hitch – others it seems no matter what I do, it simply won’t output sound. The “glitch” happens less with Android devices (or at least it seems that way), but on least one occasion I’ve had the same thing happen with the Cayin N5ii and also my X5iii.
I’d be interested to see if anyone is having similar issues – as I do know that Amos also experienced it with his review – so I don’t think its isolated just to this unit. I do hope iFi can get a Bluetooth upgrade through to the xDSD eventually. FiiO did the same with their Q5 and it made a world of difference (stability and range). If iFi could fix this issue – they’d have an absolute winner on their hands. The only solution I can find so far is getting the iPhone to “forget” the xDSD and doing a manual set-up when it happens. Its now got to the annoying stage – and would seriously influence a buying decision for me.
I’m going to preface this section with a little critique I received a while ago, and my answer to it – so that you can understand why I don’t comment on some things, and why I do comment on others. I was told my review on another amp was poor because I didn’t include sections on bass, mid-range, treble, sound-stage, imaging etc – yet referred to an amp as warm, full, or lean.
Now I can understand the reference to warm / full / lean – as they are very subjective terms, and whilst I’d like to avoid their use, they are invaluable to convey true meaning. Comparing my NFB-12 to the Aune X1S for example – the Audio-gd does sound richer and warmer. It’s the nature of the DAC and amp which is used.
But I choose not to comment on bass, mids, treble, and most definitely not sound-stage – simply because when we are talking about a DAC/amp – IMO they shouldn’t be discussed. An DACs job is to decode the signal in as linear fashion as possible, and the amp’s job is to amplify the signal with as low distortion as possible. If the device is doing its job properly, there is no effect on bass, mids, or treble – except if hardware boost is concerned. And IME an amp does not affect sound-stage (unless there is DSP or cross-feed in play) – that is solely the realm of the transducers and the actual recording.
So we have that out of the way how does the xDSD perform sonically?
To test tonality, I usually compare (using same source/transport) with my E17K. The FiiO E17K is one of the most linear devices I own, and is essentially ruler flat from 20Hz to 20kHz. Both devices were volume matched and had my iPhone SE as source. For headphones – I used the HD630VB – mainly because the E17K may have struggled a little with the HD800S.
In subjective comparison, the xDSD is different. Both have a tonally neutral signature but where the E17K is comparatively flat to the point that it can sound bright next to warmer DAPs or DAC/amps, the xDSD seems to have a slight touch of wamth, yet still remains vibrant. It’s neither dull nor overly rich.
This one is easy – the xDSD is able to convey a lot of detail, yet do it without sounding either etched or harsh. One of the tracks I use often to check cymbal realism and decay is Pearl Jam’s “Elderly Woman Behind The Counter In a Small Town”. There is a lot of crash cymbal action, and with a really good DAC and good pair of headphones you can easily hear the decay. The xDSD delivers it effortlessly with the HD600s. Switching to Nils Lofgren’s “Keith Don’t Go” from his Acoustic Live album, and every detail from the crowd, and change of fingers on the fret board is laid bare – yet the xDSD manages to do it while drawing you into the music. This is really classic iFi and I’m reminded a lot of my iDSD.
The obvious choice is the FiiO Q5 – and for that comparison we’ll use the Bluetooth connection. For the second comparison, it’ll be a DAC/amp that I know incredibly well – iFi’s own iDSD and the centre of my home system.
I used all of the devices with my HD800S (balanced with the Q5, SE with the other amps). With each test – the same files were used, volume was set and matched with test tones and a calibrated SPL meter. Listening was at my average normal level of 70-75 dB. These comparisons are completely subjective and simply my view on the differences.
As a portable Bluetooth device
iFi xDSD vs FiiO Q5
As a desktop device
iFi xDSD vs iFi Micro iDSD
This ultimately come down to personal use. If you’re adding simply as a DAC/amp wired to an existing set-up, and not using all of the xDSDs features, there may be cheaper equivalent options out there. But if I look at my own personal use:
Paired with the iPhone via Bluetooth as DAC and amplifier (and able to drive the HD800S portably around home)
- Used with my work lap-top
- Used with my desk-top if the whim took me
then the xDSD’s value increases. The hook for me would be the Bluetooth sound quality. Even with AAC, performance is on par with a high end system – and all of this via my iPhone!
For $399 with the features the xDSD (especially XBass and 3D) has, this is very good value. It is marred somewhat by the current stability issues.
Ifi xDSD SUMMARY
If I did not already have the Q5, I would more likely to be noting the xDSD’s limitations, but still claiming it as a real game changer. And in a way it is – true high quality Bluetooth is very rare, especially portably. The Q5 and xDSD both deliver – but just with a slightly different presentation.
With both devices, I can use my smart-phone, and get true audiophile sound quality.
The xDSD delivers excellent sound quality in a durable and portable form factor. It is user friendly in terms of DAC set-up, and simply plug and play use. It has very good power output and has proven to be able to handle both sensitive IEMs and full sized cans (HD800S) from its single ended output.
The xDSD does have some weaknesses, and at the moment it is not a finished product. Hopefully the primary issues can be fixed via software updates. The major bug (no sound output) happens a lot and is incredibly annoying. At times I’ll connect, and everything will look like its playing normally – but there is no sound. This happens more often with Bluetooth, but has also happened with USB. When it happens, its a matter of turning the device off, back on and hoping. Sometimes (with Bluetooth) deleting the old profile and setting up again.
So – is it worth the asking money, and does it edge out FiiO’s Q5? The answer to both questions – at the moment – is “it depends”. Sonically the two are close enough to be brothers, and depends on your preference. Personally I do like the xDSD (especially with 3D engaged) – perhaps slightly more than the Q5. But the Q5 sounds excellent, and never glitches for me. It always plays, and I don’t have to fight it to get it working. And to get the value proposition the xDSD should achieve, iFi need to fix this and fast. I’m an unabashed iFi fan – but in its current state – I’d take the FiiO Q5.
Once again thanks to iFi for allowing me to be part of the tour. My usual tabular scoring is listed below:
|Build & Design
|Inputs & Outputs
|Overall Sound Quality
|Value (based on overall performance)