iFi xDSD Review – Multi-purpose High-end Portable Bluetooth Amplifier for Headphones, Laptops, Smartphones and Digital Players

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iFi is no stranger to the portable audio market, and the ‘X’ series marks another step in the company’s development for delivering the highest quality of innovation, from design to functionality. As the first product in this series, the xDSD portable headphone DAC/amplifier, is the company’s very first Bluetooth device.
It’s convenient, compact, stylish, and works so well that you can’t complain about its setup. However, the question we want to answer in this review is: who should buy the iFi xDSD headphone amplifier and why?

iFi xDSD Versatile High-performance DAC/AMP Review

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iFi xDSD Specifications

DAC: BurrBrown DSD1793 | Maximum USB resolution: 768kHz/24-bit, DSD512 | Maximum S/PDIF resolution: 192kHz/24-bit | Dynamic range: > 113dB min | Output power: > 2.82V/500mW @ 16 Ohms, 3.8V/24mW @ 600 Ohms | Total harmonic distortion + noise: <0.005 | Output impedance: <1Ohm | Bluetooth codec: aptX, AAC | Battery: 3.8V, 2200mAh (up to 10 hours via S/PDIF, up to 8 hours via Bluetooth, up to 6 hours via USB | Dimensions: 95mm x 66.5mm x 19mm | Weight: 127 g


In addition to the soft case, the kit includes various adapters – from USB to optical 3.5 mm.

  • Three different USB wires/adapters
  • Adapter for S/PDIF output
  • Self-adhesive “sticky” pads to attach the device to the source

As you can see, everything you need is included in the kit.

Design & Ergonomy

Before introducing the X series, the manufacturer kept the same basic design and only changed the dimensions. With its metal casing, dark chrome, and beautiful grooves, the xDSD has the most unusual design iFi has ever created, so it was time for a change.

It’s not the type of USB stick DAC you slip out of your hand. However, it is significantly smaller than Micro, which the company couldn’t figure out how to make it smaller.

Also, instead of brushed aluminum, now we have a ridged surface with dark chrome. This solution, however, rather quickly collects fingerprints but also quickly gets rid of them when cleaning.

The xDSD is a bit large for a “pocket” device, but the wireless module makes it portable enough. However, in the case of a wired connection, you will probably need a carrying bag to carry both the amplifier and audio source.

You’ll find connectors controls at both ends of the device: a pair of USB ports and a universal connector, particularly from the older model that retained the implementation of a balanced headphone connection. And, judging by the specs, the power will be enough.

All controls are located on the front and back of the device.

Let’s start with the rear panel:

  • S/PDIF input
  • The USB input for connecting digital sources comes in the form of a recessed plug, making it easy to use Apple’s USB adapters and various USB OTG adapters.
  • Filter switch
  • MicroUSB socket for charging and LED indicator for battery charge.

On the front:

  • 3.5mm headphone output compatible with 4-pin balanced connector and conventional connector with common ground
  • Two different colored LEDs indicate the selected input and signal frequency (including MQA)
  • The volume control is the main control and consists of buttons and LEDs.
  • Two LEDs indicate the 3D+ and Xbass+ modes.
  • The button for switching between 3D+ and Xbass+ modes also supports Bluetooth pairing mode.

The xDSD does not amplify the analog signal but only outputs it via USB or SPDIF. The latter connects to a universal mini-jack socket, which can be made up of optical and coaxial cables.

Overall, despite the interesting LEDs that change color when changing the volume (there are seven, with red indicating “loudest”).

In addition, the status and type of connection are also indicated by colored LEDs. For example:

  • USB is white
  • Bluetooth is blue
  • SPDIF is green.
  • The other LEDs light up green until 96 kHz, then turn yellow, and finally light up white for DSD.


The xDSD uses the popular Burr Brown DSD1793 chip. iFi Micro offers a similar converter with three filter options. This time the NOS mode (called “Bit Perfect” on the Micro) has been removed, and only two listening modes remain, “Measure” and “Listen.”

In essence, the specifications of the device are very promising. However, we are talking about the frequency response of the XMOS USB receiver, not the Burr Brown DSD1793, which can handle DSD64 and PCM signals up to 192 kHz.

Now about the sound paths, the XBass+ and 3D Matrix+ boost bass and channel crossover, respectively, without affecting other parameters, and do so quite accurately, according to measurements: +9dB at 9kHz for XBass and 12dB of channel separation in 3D. In 3D, the channel separation is reduced to 12dB.

The low-level signal (-90dB) is very well reproduced in xDSD and is not drowned in noise. In general, despite its age, the Burr-Brown PCM179* series always has this parameter in order thanks to the separate processing of the upper 6 and 18 bits.

As far as the power supply is concerned, the decision to separate the inputs for charging and content is a very good one. This reduces crosstalk and saves the signal source’s battery: in USB mode, xDSD can run for more than six hours, depending on the load. A full battery charge takes about three hours, maybe a little longer.

Bluetooth quality is also good, with a range of 10 meters. As long as there are no solid walls in the way, it works well. Other reviewers have complained about the stability of the wireless connection, but I haven’t had any problems, so I guess that counts for the source as well.

Sound Quality

Before we get to the sound, it’s worth noting that there are two versions of the xDSD firmware, one with MQA and one without MQA but optimized for ultra-high resolution recording.

As such, iFi claims to try to “overclock” as much as possible, including software adjustments, until the audio limits are reached.

While xDSD resolution is indeed impressive, there is simply no material in this format to test the sound quality. Therefore, the only way to experience it is to use an upsampling mode. You can try Audirvana, but the difference is not that significant.

The sound of the xDSD is characteristic of the company. Nevertheless, some changes have been made. The highs are a bit softer, the bass is more pronounced and very organic.

The sound amplifier works very well, and the 3D+ is expectedly some variant of crossfeed, which improves the soundstage and adds depth. This works well with older tracks, as they were often mixed without headphones.

The effect is a bit artificial with contemporary music, but that’s a matter of taste; the Xbass+ adds weight to the bass range and some warmth to the sound, but it does so in a very subtle and delicate way.

The bass here is very well controlled and has just the right depth. It never gets too low and never lacks natural music. The tempo is also excellent, just as the delivery. Also, the bass instruments sound very natural and are well separated.

The mids are also fantastically reproduced, and the XDSD not only helps musically but adds body and warmth that enhances the natural sound of the instruments and voices (especially male). It’s not a device for listening to the smallest details of sound, but you obviously can’t complain about the resolution here. The recording is very correct, and the emotions are highlighted with precision.

Overall, the Bluetooth listening experience is a pleasant surprise. Admittedly, the sound is relatively basic, especially in the high frequencies, but it is not a mess.


Obviously, with iFi’s experience, the company couldn’t create a bad device, so once again, they’ve managed to create an excellent headphone amplifier.

The xDSD refreshes the company’s product line with a bold and unusual look accompanied by a revised sound signature, and Bluetooth support is a nice touch for modern smartphone users.

The xDSD’s power reserve is also quite good but not exceptional. So, it will rock most headphones with no problem, except for really demanding models. However, there are amplifiers from the iFi’s Micro series for the latter, which can be used without problems.

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