- Neutral sound with reference level.
- High build quality.
- Very good design, attractive and highly functional.
- Very versatile.
- Two gain modes, two USB modes, precise volume control, playback control and status LED.
- Quite powerful.
- Comes standard with a USB Type-C to Lighting cable.
- It’s not as powerful as the specifications indicate.
- It could be more powerful for 100Ω impedances.
Link to the Store
Shenzhen xDuoo Technology Co., Ltd. has long since changed its aesthetics. After creating more than 100 models and with a number of patented technologies behind it, xDuoo has acquired a distinctive design of its own, mixing the grey of the metal with the red and black of the background of some of the glass surfaces. These three elements seem to be in many of its current products. Of course, they are also in the new Link2 Bal. On the other hand, a brand that is so acclaimed for its amplifiers, needed to make a splash in a segment as tough as the dongle segment. Undoubtedly, this group of devices is possibly one of the products that have proliferated the most in recent years. There are brands that are experts, creating one new model after another, always with a different feature. Others have one or more models, iterating over time to add new features, more up-to-date DACS, even controls or more power. Xduoo wanted to present a reference device, not just a mere sound card, but something superior. To this end, it has built the Link2 Bal in an emblematic way, with all the details of its design line, with a striking red button, on a sandblasted metal body, whose faces are glazed with a dark background. Of course, there are volume controls, two outputs (SE 3.5mm and BAL 4.4mm) and something else: a USB mode control (UAC1.0, UAC2.0) and a gain selector (Normal and Turbo). Inside, xDuoo has opted for the now classic Dual DAC CS43131, along with a TI LM27762 chip capable of providing 250mA to the amplifier circuit. The rest of its features will be presented in this review.
- DAC Chip: CS43131 x2.
- Input port: USB Type-C.
- Output port: SE 3.5mm and BAL 4.4mm.
- Output power 3.5mm: 125mW@32Ω.
- Output power 4.4mm: 270mW@32Ω.
- Frequency response: 20Hz+20kHz (±0.5dB).
- THD+N output 3.5mm: 0.001% @ 1kHz.
- THD+N output 4.$mm: 0.0007% @ 1kHz.
- SNR output 3.5mm: 123dB.
- SNR output 4.4mm: 123dB.
- Crosstalk output 3.5mm: >= 77dB.
- Crosstalk output 4.4mm: >= 120dB.
- Support sample rate: PCM: 16-32Bit/44.1-384kHz, DSD: DSD64-256.
- Weight: 28g.
- Size: 63×23.5x13mm.
The xDuoo Link2 Bal comes in a blue, elongated box with dimensions 145x80x34mm. The main side, if read in landscape mode, shows the model name, in large letters. The letters «Bal» are inside a large orange dot that emulates the design of the device’s own red button. The rear face also reads in landscape mode. In the lower left-hand corner are the brand’s markings, and in the right-hand corner are a pair of barcodes and the logos of the certifications it holds. After removing the outer cardboard, a white box with the brand logo inside a printed circuit board can be seen, all in soft grey ink. Lift the lid and the product sits in a white foam mould. Beneath which are two cables, a USB adapter and documentation. In summary, the complete contents are as follows:
- The xDuoo Link2 Bal.
- 1 USB Type-C to Type-C cable.
- 1 USB Type-C to Lighting cable.
- 1 USB Type-C to Type-A 3.0 adapter.
- 1 instruction manual.
- 1 warranty card.
The packaging is not far from the competition in terms of size and content. But xDuoo has managed to harmonise the external design with the product design. On the other hand, there are a couple of details that catch the eye: the inclusion of a Lighting cable, something that most of the time is a separate accessory, and a USB Type-A 3.0 adapter, when most people still use USB 2.0.
Construction and Design
The xDuoo Link2 Bal is a beautiful piece that combines sandblasted aluminium with two layers of double-sided 2.5D glass. The entire piece has been CNC machined, there are no screws or gaskets. Its dimensions are 63×23.5x13mm and its weight is only 28g. On the main side, at the top, there is a small horizontal LED that changes colour depending on the format reproduced. On the base is the logo of the brand and the name of the model. This can be seen behind the glass, as if it were a mirror. On the back side, in landscape mode, you can read (in grey letters) the web address, where it has been manufactured and some logos of the certifications it complies with. On the left side there are two selectors: the one on the left allows you to switch between USB UAC1.0 and UAC2.0. The one on the right allows you to select the gain mode, Normal or Turbo. Near the bottom right corner is the serial number. All legends are written in white ink and, although the print is small, the indications are clear. On the other side are the volume controls, a large red button used to control playback and the Hi-Res Audio sticker. On the top edge is the USB Type-C input and on the bottom edge are the audio outputs. On the left is the balanced 4.4mm connection, whose edge is metallic and gold-plated. On the right is the 3.5mm SE connection, which has a plastic rim.
Inside, the Link2 Bal uses a Dual DAC CS43131 from Cirrus Logic. It also uses a TI LM27762 chip to guarantee a high power supply to the amplifier stage.
The design has all the key features characteristic of the current xDuoo line. It has no screws and looks like a very solid piece. It is clear that the glass panels attract fingerprints, but it is forgiven for its beauty and build quality. The playback control button, which actually works, is a real eye-catcher. In addition, the USB mode control is truly distinctive and very useful for making the product compatible with most USB connections. It’s also unusual to have a gain selector on the body itself, so it’s a welcome addition. On the other hand, those selectors are very well integrated into the body of the product and barely protrude, so they don’t easily move around when handling the device, or putting it in your pocket. Very well thought out.
The xDuoo Link2 Bal, thanks to its USB mode selector, is able to connect to a wide range of sources. It can be connected to PCs and has an ASIO driver. It can also be paired with tablets, iPhone, Android, even consoles such as the Switch. It is compatible with many music streaming platforms (Tidal, Qobuz, Spotify…). It supports a sampling rate of up to 384kHz and 32Bits deep, it can play up to DSD256. On a positive note, to connect to an iPhone, there is no need for an additional cable, because it comes with one as standard, which is unusual for its competitors.
The handling is somewhat more extended than a simple dongle. It has a USB mode selector, which makes it compatible with more sources. It also has a gain selector (Normal or Turbo). It has two buttons to control the volume (in Windows it allows to vary the volume in steps of two). Playback can also be controlled with the red play/pause button, which is compatible with many DAPS, including Windows players.
The operating LED indicates the sample rate, as follows:
- Red: 48k/44.1kHz PCM
- Blue: PCM 88.2k-384kHz
- Green: DSD 64-256 (DOP-NATIVE)
The Link2 Bal has ASIO drivers and can be downloaded from the xduoo website:
It is worth remembering that it has no battery. The heat emitted is low, despite connecting it to headphones that demand a lot of power, I didn’t notice that it got very hot. Very good in this respect.
According to the specifications, the Link2 BAL is capable of delivering 270mW at 32Ω on the 4.4mm balanced output in Turbo mode. While on the SE output, it delivers 125mW at 32Ω, in Turbo mode.
This means that the balanced output is capable of over 91mA of current delivery, that magic figure that few dongles reach, approaching 3V. On the SE output, 62.5mA is delivered, giving a voltage of 2V. In reality, this is not entirely true. We will see in each corresponding section, its measurements.
No load SE
At the SE output and in Turbo mode, with no load and over the entire frequency range, a voltage of 2.1V is obtained.
15 Ω SE
On the SE output and in Turbo mode, connecting a 15Ω impedance, the maximum voltage without visible distortion is 1.26V, which means a power of 110mW and 84mA.
33 Ω SE
On the SE output and in Turbo mode, connecting a 33Ω impedance, the maximum voltage without visible distortion is 1.97V, which means an approximate power of 120mW and 60mA. This value is very close to the 125mW specified and we could say that in this section, the specifications are true.
100 Ω SE
For the SE output and in Turbo mode, connecting a 100Ω impedance, the maximum voltage without visible distortion is 2.07V, which means a power of 43mW and 21mA.
As the voltage is the same as without load, the output impedance of the SE connection tends to zero. It is probably less than 1Ω.
No Load BAL
At the BAL output and in Turbo mode, with no load and over the entire frequency range, a voltage of 4.2V is obtained.
15 Ω BAL
On the BAL output and in Turbo mode, connecting a 15Ω impedance, the maximum voltage without visible distortion is 1.27V, which means a power of 110mW and 84mA. This is almost the same as the SE output. This is the maximum current delivered by the system.
33 Ω BAL
On the BAL output and in Turbo mode, connecting a 33Ω impedance, the maximum voltage without visible distortion is 2.46V, which means a power of 180mW and 75mA. As can be seen, this is a little short of the 3V needed to reach the specified power of 270mW at 3V, with a current delivery of 91mA. If the maximum current delivered in my tests was around 84mA, I thought that with this impedance, the power would be higher. But it wasn’t.
I measured the output impedance with 33Ω, at 1kHz, with an output of 1V, at high gain. At no load it gave 1.04V, while at load it gave a measurement of 1V. This implies an output impedance of 1.32Ω.
100 Ω BAL
On the BAL output and in Turbo mode, connecting a 100Ω impedance, the maximum voltage without visible distortion is 3.67V, which means a power of 130mW and 37mA. This does not reach 4.2V at no load and is not very understandable, when the system is clearly capable of delivering more power. This may explain why it doesn’t quite work to its full potential with high-impedance headphones.
The frequency response is completely flat, from 10Hz to 40kHz, with excellent linearity. In addition, the response of each channel is fully matched, there is no crosstalk. As it should be in a reference device, which also has a very low output impedance.
The profile of the xDuoo Link2 BAL is very neutral, without a hint of darkness, with a remarkable amount of clarity and balance. You could say that its sound is unspectacular, because it is not at all gimmicky. It doesn’t seek to surprise, it doesn’t stand out for one characteristic more than another, unless it is for the level of fidelity. In this sense, naturalness is the basis of his profile. It has a more realistic tendency than an analytical one, without this implying a lesser degree of detail, but more of an analogue colour than a digital one.
The first impression is of a more realistic presentation, without the scenery possessing an attention-grabbing level of spectacularity, or producing a sense of music out of the head. I think that, initially, the most notable points are the cleanness of the sound and the level of fidelity that is noticeable. All of this results in a highly neutral and flat response, with no favour shown to a particular band. The second point to note, after checking the balance provided, is a rather pure sound sensation, which goes beyond an analogue perception. I tend to pair a more analogue sound towards warmth. In this case, I don’t contemplate a hint of warmth in the sound of the Link2 BAL. Nor coldness, though. Rather, coolness was my initial feeling, after evaluating its sound for the first time. As a reviewer and more, as an amateur, one tries to look for that Wow! effect, after testing any audio device. However, this did not occur in my initial impressions. My thought was: I will have to spend many hours to be able to describe this sound. But, in fact, this was not the case. The Link2 BAL is very serious, a great audio device, very refined in its technical capabilities and extraordinarily clean and uncoloured. The result is a reference sound, which is aligned with a more absolute fidelity, offering, in addition, freshness and light. The freshness has to do with the speed of its attack and the lightness with its level of dynamics. It is not an energetic sound, but it is alive. There is life in the sense of movement, of speed, but it is not energetic because it doesn’t feel so vigorous or muscular. It has a more restrained, measured, realistic sense of power, maintaining a natural level of power. In this way, the sense of expansion of the image, and also of the musical notes, is more fixed, not so ethereal. This characteristic means that the detail is shown in a more implicit way, without being lost in a more vain or futile propagation. But this sensation should not be confused with the generation of a more compact sound. Again, the Link2 BAL offers plenty of light, great separation and excellent resolving power. At this point, the detail feels more complete, more in tune with the music, part of its intrinsic nature, as something indissoluble. This fact results in a greater richness of nuance, a higher degree of resolution, a level of detail inherent in the sound emitted by the Link2 BAL. At first, it is not easy to notice this aspect. You get the feeling that the music must sound like this and you assume that the sound of the xDuoo is conventional. Not at all. That level of naturalness and ability to sound easy is not on a par with many dongles. Where others strive to generate a sound that stands out in some way, the Link2 BAL pushes the envelope of purity, offering naturalness and a high degree of fidelity. Without a doubt, this is a portable Hi-End device, a dongle that could be the paradigm of this website (HiEndPortable).
Digging on the side of purity and naturalness, this dongle offers a very accurate timbre, enhancing the original sound of the connected headphones. If I had to choose one source as a reference in this respect, I would definitely choose the Link2 BAL, thanks also to its tonal balance, as well as its tremendous neutrality.
Another aspect derived from this side, is the way in which the notes are finalised. As I have mentioned, there are times when with other dongles or sources, the drawing of the nuances is blurred or separated from its fundamental, giving a sensation of lack of resolution or musical volatility. In this case, this sensation is minimised to a very low level. The notes are described in a very complete way, resulting in a sound of very high resolution, in which there are no losses, neither in the details nor in the harmonics. This can also be appreciated at both ends of the audible range: in the lower range, the bass has a complex development, with a high level of dynamics, capable of offering a pronounced control and a great speed in its attack. Thus, the descriptive level of the lower range is very high, rich in texture, layering and depth.
At the other extreme, the treble remains close to the core, retaining all the power of definition without losing an iota of control. This is the way to generate a reference sound, able to shine in a way that is so simple, it seems easy. As a result, the midrange is an exhaustive exercise in naturalness, under a simple appearance, a sound that is easy, light to digest, but extremely exquisite, even lush.
In other words, the xDuoo Link2 BAL is the epitome of high fidelity.
Tempotec Sonata E44
One of Tempotec’s best dongles, if not the best, is the Sonata E44. Tempotec hit the nail on the head by tuning the same Dual DAC as the xDuoo Link2 BAL, the CS43131 x2. In the case of the E44, I was very struck by the great sense of separation and volatility of its sound, getting a more spectacular feel to the sound, in exchange for losing some realism, but offering a closer and more splashy perception of details. After a quick switch between the two dongles, there is a point of lightness in the xDuoo, but the vaporous feel is lost. The sound is tighter, more connected, more cohesive, the scene doesn’t expand as much, nor does the detail volatilise. The feeling is clearly more natural and realistic. Three-dimensional perception is lost. Elements have a more contrasted ability of closeness, proximity, remoteness and depth in the E44. It’s not that Link2 is flat, but it doesn’t focus on describing depth as the E44 does. In contrast, the xDuoo presents a reference level of timbre, a higher level of neutrality and purity. This is demonstrated in the high end, where the treble is drawn more accurately and with better resolution, there is a higher level of definition that outlines the high notes in a more realistic and complete way, allowing the range to be felt more effectively. In the E44, the highs tend to separate and become more diffuse, not as well defined as in the xDuoo.
The lower range is also more concrete in the Link2, feeling quicker, with a more concise stroke and superior recovery. Meanwhile, in the E44 there is a point of greater rubberiness, a little more energetic feel, something that adds a hint of more texture to the finish, a more perceptible and evocative rough vibe. The Link2 describes the lower range in a canonical way, while the E44 is driven by a more pronounced effectivity, which gives a more spectacular feel.
In the mid-range, the xDuoo’s greater capacity, both in resolution and definition, is able to bring more complexity to the sound, but in a natural and simple way. The E44, on the other hand, doesn’t seem to have the ability to show as much richness in the midrange, leaving more diffuse fringes. The greater sensation of speed, the faster and more precise attack, draw more concentrated and faithful nuances in the Link2, which endows the sound with a higher degree of fidelity.
As for other non-sound issues, both dongles have volume control. Connected to Windows, the E44 has 32 steps and the Link2 50, it is clear that the xDuoo is more convenient in this respect, as the jumps are larger on the Tempotec. The xDuoo has a gain control, USB mode control and a play/pause control button. The E44 does not have any additional controls besides the volume control. The xDuoo has two outputs (SE 3.5mm and BAL 4.4mm), while the E44 can use a serial adapter, which allows it to be used as a 3.5mm output. The size of the Link2 is clearly larger, but it has no additional cables attached to its body. On the E44 the connections are outside the body, attached to separate cables. The Link2 has an LED that informs about the played format. There is no LED on the Tempotec. At the time of writing, the price of the E44 is very close to €100, while the Link2 is over €160.
xDuoo has made it very easy to generate music. The feeling of the new Link2 BAL is that it goes further than other dongles, if you use fidelity level as a benchmark. There are other models that try to achieve a high degree of naturalness, neutrality and purity, but they remain at a lower level, at a point where their sound does not quite assume the level of reference that this xDuoo does. At that point, the competition becomes futile and the Link2 BAL seems to just do its job, only much better. It is at this point that this dongle becomes a benchmark, as it raises the level of playback to a point that others have not reached. And the best thing is that it achieves this without fuss, without artifice and without losing what is most important in music reproduction: high fidelity. In this sense, the xDuoo Link2 BAL crosses the barrier, becoming a clear paradigm of a portable Hi-End device, a source that exemplifies the art of reproducing music in the most simple, natural and pure way.
But the best thing is that this dongle is not just about music, it also sets itself apart from the competition with an eye-catching construction, mixing a textured aluminium chassis with two 2.5D glass plates. In addition, it has a large volume control, a play/pause button, gain control and USB mode control, as well as an LED that indicates the played format. Of course, its input is USB Type-C and it has two audio outputs: 4.4mm BAL and 3.5mm SE, both with a high power level. In this way, the device becomes a highly versatile system, with great connectivity capacity, even with consoles, as well as offering a very high operating level. In this way, the xDuoo Link2 BAL is not only a reference in terms of sound, but also assumes this level in all other areas.
Earphones and Sources Used During Analysis
- HiBy R3 Pro
- Tempotec V1-A
- Xiaomi Redmi Note 8 Pro
- NiceHCK Topguy
- ISN H40
- Rose QT9 MK2
- BQEYZ Autumn
- Ikko OH2
- Ikko OH1s
- Yanyin Aladdin
- Dunu Titan S
- Dunu Falcon Pro
- TFZ Tequila Pro
- Penon Sphere
- NiceHCK EBX21
- NiceHCK EB2S
- Hessian Ansata Pro
- Rose Martini
- Takstar Pro 80
- SoundMagic HP150