iFi xDSD Review

Price: 399€

Where to buy: https://amzn.to/2AKYdYg

Specifications (from https://ifi-audio.com/products/xdsd/):

  • USB Input: up to PCM768kHz & DSD512 (24.6/22.6MHz)

  • SPDIF Coaxial and Optical Input: up to 192kHz/24Bit

  • Dynamic Range: > 113dB (A)

  • Volume Control: -101dB…0dB in 1dB steps

  • Output power:

> 2.82V/500 mW @ 16 Ohm
> 3.7V/270mW @ 50 Ohm
> 3.8V/48 mW @ 300 Ohm
> 3.8V/24 mW @ 600 Ohm

  • Line out Level: > 2.1V @ 0dBFS (& 0dB Volume)

  • THD &N (1V/16R): < 0.005%

  • Output Impedance: < 1 Ohm

  • Battery: 3.8V/2200mAh

  • Dimensions: 95 (l) x67 (w) x19 (h) mm

  • Weight: 127g (0.28 Ibs)

Thanks to iFi Audio for providing to us this loan unit to test.


Unboxing and first impressions

iFi is a brand who knows how to present a product. We have in test the xDSD as well as the SPDIF iPurifier: they both have a white box with a render of the product on the front and sides, while on the back there are all the useful information about the product itself and its technical specifications. The xDSD won the EISA award for being the best product of 2018/2019 and they proudly attached a sticker on the front of the box to let you know that, next to the Hi-Res one to attest this certification by the Japan Audio Society (aka Sony, in less words) and another one to inform about the Direct Stream Digital support up to “512” (that means the sample rate is 512 times the one of a Compact Disc – not a SACD, which is in fact the DSD physical support). Other useful or less useful information on the stickers: the MQA support, a new lossy format with the same audio characteristics of a FLAC lossless format, but without the same weight; the Bluetooth functionality; a 3D virtualizer as well as a bass booster. The box reports all the inputs you can use the xDSD with: Bluetooth (wireless, obviously), USB (wired) and S/PDIF (wired: optical or coaxial). Some info about MQA: it’s actually supported by TIDAL in Master quality, which is the source I’ve used to test the xDSD with this format, by a MacBook Pro and a Xiaomi Mi MIX 2 (which however I’m not sure if can natively support it or there are some kind of conversions in the process). MQA exist even in physical support via CD. It works by “unfolding” the file, once, twice or three times to unveil the details MP3 cannot provide; the more the hardware is capable of decoding, the more the unfold process is revealing. This is actually a nice explanation of how it works, which however may not interest the average user; what’s important is that the quality is even superior to the one of a CD (can I hear it? No), but the storage is less affected than a lossless file. Speaking of lossless files, this device can read PCM up to 192 kHz (highest Hi-Res available) – here you understand why MQA in theory could be even better: it provides up to 384 kHz –, DXD (same sample rate as MQA) and DXD2x (double the previous rate), as well as DSD like I’ve previously mentioned. Natively. So, it does not convert to PCM like other devices which namely support DSD but only after conversion.


The xDSD comes with some accessories: a blue cable (USB type A male to type A female), some papers (some really poor and counterintuitive instructions, a help to set up MQA, a help to connect iOs or Android devices to that strange USB type A male port on the back of the device). There’s also a paper which informs about the pre-installed firmware, which is optimized for MQA – so it downscales the maximum DSD supported to 256. This same paper actually says that PCM could reach up to 768 kHz with the firmware non-optimized for MQA, and half the rate with the other: this actually confuses me, because it must be a mistake on the box, which reports “192 kHz” at max. A useful adapter is included, which converts the USB A male to a USB B female, much more common and convenient (most of the audio interfaces use this standard). There are some Velcro straps to stack the xDSD with other devices.


The chrome finish of this portable DAC/Amp leave me bittersweet: it’s a so-called fingerprint magnet and I really don’t appreciate this choice. However, when well kept, this feels like a premium device. The shape is particular but gives character to the device and it helps when you need to handle it. Where they located the BT antenna there’s a matte black plastic section, on the back, which also houses the S/PDIF port, the USB A male for the USB connection, the toggle for the filter (a switch from “measure” to “listen”) and the USB type C for charge. There’s no sense at all in the choice of mounting a USB C just for charging. The XDUOO XD-05 Plus is a similar device and it has another type C for the data: clever update from the XD-05 base model, which is similar to the previous version of the xDSD, without the type C port. I don’t own that model by XDUOO, however there’s another choice I’d rather there than here: the display. I have a color disease, so it’s impossible for me understanding, by looking at the big front LED, how many dB are provided. In fact, the analogic volume knob of the xDSD houses a big LED with the iFi logo embedded, which changes not only due to the volume, but also due to the mode you are using (wired/wireless). There are other smaller colored LEDs, which are useful for understanding the sample rate in use as well as the chosen input (same thing as before: for me and other 12% of the male people, colors are not useful at all); other two leds are helpful to activate the 3D virtualizer, the bass booster or both together. These last LEDs are white, at least.


Sound and comparisons

There’s one device I can compare the xDSD with: the XDUOO XP-2, which costs ¼ of its price. I’ll soon have the TOPPING NX4 and I’ll update this review by adding that comparison, too.

I made some chains for trying the xDSD (using a lot of IEMs, like the UfoEar Ufo-112, the BGVP DM6, the AudioSense T800, the Sennheiser Momentum On Ear, the 1MORE MK801…):

  • FiiO M7 via USB;

  • FiiO M7 via Bluetooth;

  • FiiO M7 via line-out;

  • Dodocool DA106 via line-out;

  • MacBook Pro 2012 via USB;

  • MacBook Pro 2012 via Bluetooth;

  • Mac Pro 2008 > Fireface 800 > SPDIF > 75 Ohm RCA cable > iPurifier > optical out > xDSD > AudioSense T800

  • CD coax (JVC XL-Z331) > iPurifier > xDSD

I used the xDSD just for listening, so the toggle never went to “measure”.

A bad thing about the xDSD is that it’s not intuitive, so switching between modes is not easy. And the only way to do it is by following the – poor – instruction manual. Anyway, something I couldn’t try was the balanced output via 3.5mm jack, because I only use and own unbalanced gear. The xDSD has properly worked most of the times, but with the last chains I had to restart it more than once. I believe these are issues which can be solved by updating the firmware.


I would describe the sound of the xDSD as smooth. I don’t find it ultra-revealing, the details are there but I don’t have the impression of something analytical. I find it, instead, pretty fun to listen to, with a bodied mid-bass – which can be boosted by pressing the dedicated button – and an average soundstage. Even with the surround virtualizer, the holographic sense of space feels artificial and doesn’t help improving the perceived stage. Here I think it’s a problem of imaging: there isn’t a clever distribution of the instruments among the physical spectrum, but they are all placed… somewhere. I’d rather the behavior of the XP-2: it doesn’t provide a giant soundstage, but there’s a clear separation of the space between the various instruments. Also, even though I sincerely believe the xDSD could reach more extreme frequencies up and down, I’d take the XP-2 for the sub-bass – both for its juice and for its clarity. It’s a general fact: the XP-2 feels punchier and flatter, while the xDSD feels warm and a bit “loose”. That said, I find it coloring, but just on the mid-bass range, while it is pretty respectful on the mids and treble area. In fact, by trying the M7 both standalone and with it, I didn’t catch many differences, except the bass bump and much more output power – which I don’t really need as a (mainly) IEM reviewer. The XP-2 here cannot rival: its output power is much lower.


I truly believe the xDSD has to be used wirelessly. Via Bluetooth it’s a really nice machine, with a good battery – not great, though: it does 5/6 hours with my use – and a clean sound with a really dark background. But if you go wired, it’s another story. It catches all the static electricity of your setup – trivially, when my Mac is connected to its power brick, the background noise feels unacceptable through the xDSD. My Scarlett 2i2 doesn’t suffer so bad from this same problem, but it’s there, too. The XP-2 doesn’t suffer at all. Knowing that iFi sells signal purifiers, I don’t want to think they are going to economize on the isolation of their hardware to induce you buying their trinkets. Speaking of them, the iPurifier – little spoiler – is a good device for music listening, but not for music production: it literally cuts off the upper treble to mitigate the sibilance. So, if you are very sensitive, it could be useful, and it matches nicely with the xDSD, but if you need to hear all the details you have to avoid it.


As always, I’ve used my offline files – from DSDs to FLACs to ALACs to MP3s to M4As – but this time I’ve also tried TIDAL Master to try this new famous MQA format. Well, it doesn’t make any differences to your ears, just on paper. TIDAL sounds great and it surely is a step above Spotify in terms of cleanliness, body and detail. I’d say it’s on par with my offline files, which is, well, the most important thing, in my opinion. And I’ve tried a CD (“Human Nature” by Michael Jackson, in “single” versione and in “album” version, both amazing Japanese editions) which – maybe thanks to the hardware of the source (JVC XL-Z331) – was the most detailed and better sounding version of all. The xDSD handled every one of them with ease. So, I have to give it credit for its remarkable versatility.

Let’s say something more about switching modes. To switch, you have to turn off the device, then turn it on again but without releasing the button, until the color changes. This is not intuitive, but at least it’s understandable. I link here the user manual, so you can judge by yourself. Good engineering, bad design. https://ifi-audio.com/wp-content/uploads/2018/07/xDSD_Manual.pdf



The xDSD is an interesting piece of hardware. I’m conscious I couldn’t take advantage of all its potential – mainly because I don’t own any balanced adapter or gear – but I find the price of it to be way higher than what it offers. If you need a tool which can be used for everything, though, it could be a choice: it works as a Bluetooth receiver, as a DAC/Amp or just as an amp, with all kinds of connections and formats and all OSs, natively. With a cleverer use of the ports (type C also for USB connection) and something more intuitive than colored LEDs (a display CASIO-style, maybe), this could be a more recommendable product for me. The audio quality is great, don’t get me wrong, but for the price I would expect something more.



  • Build quality

  • Output power

  • Versatility

  • Supported standards

  • Good battery

  • It matches pretty good with all IEMs

  • Bluetooth range



  • Not intuitive at all

  • Totally incorrect input equipment (USB C just for charging, USB A male for data?!)

  • 3D and bass boost toggle are a gimmick

  • Low value for money

  • Not colorblind-friendly

  • It gets dirty too easily