Hidizs XO English Review


The Added Balance




Construction and Design
Packaging and Accessories:




  • Very precise, structured, versatile, rich, detailed sound, highly suitable for monitoring.
  • Great level of clarity, transparency, resolution and definition.
  • Great technical ability.
  • Wide soundstage, great laterality, good headroom, good positioning.
  • Balanced output improves the sound.
  • Very light in weight.
  • RGB LEDS with 15 different lighting modes.
  • Two sound filters.
  • High level of construction, the side panel with H-shaped holes is very precise.
  • Very powerful, especially for low impedances.
  • Quality USB converter.
  • Ultra low output impedance.




  • Slight overheating.
  • USB cable could be better.
  • The image is frontal, with an average depth.


Purchase Link




Link to the WEB






Hidizs is really active lately and is not losing any ground in the dongle market. It takes advantage of its experience with the Sabre Dual ES9219C SoC, which it has used in its latest DAPS, to implement it in its latest creation. This is the XO dongle, which also knows how to follow up on the taste of RGB LEDs, to adopt it as an attractive sales strategy. Of course, it also supports MQA x16, has two 3.5mm SE and balanced 2.5mm audio outputs, a sample rate indicator light, an O button to switch between two filters and an X button to switch between 15 different lighting effects. Yes, the XO has side grilles with H-shaped holes, through which you can see the RGB lighting set via the X button. It is capable of decoding up to DSD256, PCM 32Bit/384kHz, has an ASIO driver and is compatible with the HiBy Music application. All this in a rather restrained aluminium alloy body, which can be chosen in three colours.
It is being prepared for launch on Kickstarter at $89. The final price will be $99 on the Hidizs website. Let’s take a look at the rest of the features and, of course, we’ll talk about its sound.





  • Independent Oscillator Crystal.
  • MQA x16: requires use of software to cooperate, such as HiBy Music.
  • DSD: Native DSD64/128/256.
  • PCM: Support up to 384kHz/32Bit.
  • Sample rate indicator light: 5 colours.
  • RGB LED Illumination: Support up to 15 different modes.
  • Build quality: CNC machined aluminium alloy.
  • USB interface: Type-C.
  • Audio Outputs: Single-Ended 3.5mm, Balanced 2.5mm.
  • Frequency response: PO(3.5): 20Hz-40kHz(±0.12dB) / BAL(2.5): 20Hz-40kHz(±0.12dB).
  • THD+N: PO(3.5): 0.0015% / BAL(2.5): 0.0005%.
  • SNR: PO(3.5): 118dB / BAL(2.5): 119dB.
  • Crosstalk: PO(3.5): 76dB / BAL(2.5): 118dB.
  • Output power: 3.5mm SE: 78mW @32Ω. 2.5mm BAL: 195mW @32Ω.
  • Supported systems: Android, Windows, Mac OS, iPad OS, iOS (Lightning to Type-C adapter must be purchased separately).
  • Dimensions: 55×24.5×9.35mm.
  • Weight: 11g.





Hidizs is known for its small packaging and the XO is no exception. The new dongle comes in a very small, almost square, black box with dimensions 76x75x39mm. On the front side you can see a real picture of the XO on a black background. On the bottom left is the name of the model, as well as the description and logos of the certifications it meets. On the right side is the Hidizs logo, all in holographic ink. On the back are the specifications, both in English and Chinese, in white ink. After removing the outer cardboard, a black plastic box appears, with the brand’s logo and slogan inscribed on the lid. On one side there is a sticker with the CE certificate and another with the model name, between two linear barcodes. On the other side, there is another sticker with the name of a server (more on that later). After opening the box, the dongle is embedded in a foam mould lined with black cardboard. There is a strap to pull it out. The dongle is protected by a cellophane bag. The complete contents are as follows:


  • Hidizs XO dongle.
  • A short USB Type-C to Type-C cable.
  • One USB Type-C female to Type-A male adapter.
  • One warranty certificate.
  • One serial number card.
  • One Hidizs VIP card.


The contents are just right. There is no carrying pouch, almost no dongle comes with one, so it can’t be an honest review. The USB cable is short and simple. I like the USB Type-C female to Type-A male adapter, it’s nice that it’s so small and of good quality.



Construction and Design


The Hidizs XO is a really small aluminium alloy tablet. Measuring 55×24.5×9.35mm and weighing a very light 11g, it really is very compact. It may be a little wide compared to the S9 Pro itself, but its all-aluminium body and bevelled edges make it stand out from the crowd. Of course, the most striking feature is its side panels with H-shaped holes, through which you can see the 15 lighting effects, which can be activated by pressing the X button in succession. There is another button on the front face, close to the USB connection, which is an O surrounded by an LED ring indicating the sampling frequency with its colour. The mark is inscribed on the part near the audio outputs. These outputs (3.5mm SE and 2.5mm BAL) are plastic connectors (not gold-plated). The USB Type-C connection is recessed in the tablet. Only a few inscriptions can be read on the rear side: the ESS logo and MQA on the top left. The supported formats and the product description at the bottom left. Finally, Hidizs has been kind enough to inscribe the name of this humble WEB on the top right (Thank you very much!). That’s why the box came with a sticker with my reviewer alias on the outside. This is the first time this has happened to me and it was really exciting to see it in my hands.
The aluminium has a micro texture that gives it a nice roughness, but also prevents it from being a fingerprint magnet. The panels with the H-shaped holes look perfect and should not be an easy fabrication. The bevelling is also quite precise, as are the inscriptions. But I do miss a 4.4mm output instead of 2.5mm, as well as gold-plated connectors. It is true that a 4.4mm output would have required a larger pickup thickness. The width of the dongle is justified by the RGB LEDs, which, on the other hand, can be an eye-catcher, but on the other hand can lead to a higher power consumption of the power supply to which the dongle is connected.
Finally, it is available in three colours: black, silver and rose gold.





The Hidizs XO is compatible with Android, Windows, Mac OS, iPad OS, iOS. For Windows 10 and above, no additional driver is required and it has an ASIO driver, which is highly appreciated. Allows exclusive mode with the HiBy Music APP. It has official MQA 16x certification (with the help of HiBy Music). It does not support microphone.
Finally, the Lightning to Type-C adapter must be purchased separately.





No volume control. Decodes MQA, DXD, DSD 64/128/256 natively. Supports 32-bit PCM up to 384kHz. Supports exclusive mode for all platforms. ASIO drivers. Connects in exclusive HQ USB Audio mode with HiBy Music APP. It has a multi-colour LED status indicator:


  • Red: PCM 352.8/384kHz.
  • Pink: MQA
  • Yellow: PCM 176.4/192kHz.
  • Green: PCM 44.1/48/88.2/96kHz.
  • Blue: DSD64/128/256.


It has an O button to switch between two sound modes (red and blue filter). It has an X button to switch between 15 different lighting patterns. The RGB lighting modes are independent of the music. Of course, the illumination can be switched off.
There is no volume control. The volume steps in Windows are the usual 100.
It only heats up slightly, very little.
It runs smoothly and there are no problems connected to Windows, something I have noticed on other dongles with the same Dual DAC, where the Foobar2000 hangs.





Hidizs does not usually lie in its specifications. On the contrary, it tends to err on the side of caution. And that’s something you notice after you’ve measured it.
As usual, I usually turn the volume up to the limit just before I notice visible distortion. I use pure sinusoidal amplitude 1. I use the Hidizs connected to my PC used as a DAC/AMP via Foobar2000, using the ASIO driver.


No load SE


Not much to complain about, 2.07V at 1kHz.



15 Ohms SE


1.28V @ 1kHz Power: 110mW Current 85mA. A great value.



33 Ω SE


1.71V @ 1kHz Power: 86mW Current 51mA. The specs say 78mW, excellent.



100 Ω SE


2.03V @ 1kHz Power: 41mW Current 20mA. Not bad at all, I only notice a subtle distortion visible at full power.



No Load BAL


4.11V @ 1kHz.



15 Ω BAL


1.78V @ 1kHz. Power: 210mW Current 120mA, simply enormous, it exceeds the 90mA barrier, leaving the brand in tatters.



33 Ω BAL


2.66V @ 1kHz Power: 210mW Current 80mA. Again, above the specified value.



100 Ω BAL


3.93V @ 1kHz Power: 150mW Current 39mA. Again, at maximum volume I notice a subtle distortion.



Frequency Response


The frequency response is flat in the audible frequency range and has only a minimal difference between channels which is not audible.



Output impedance


The measured SE output impedance for a 33Ω load at 1v at 1kHz is practically zero. There is no voltage difference between the measurement without load and the measurement with load.



The measured BAL output impedance for a 33Ω load at 2v at 1kHz is practically zero. There is no voltage difference between the unloaded measurement and the loaded measurement.





Again, the Sabre Dual ES9219C SoC is being used, the same as the one used in the Hidizs AP80 Pro-X. So I don’t expect a different sound. I think SoCs leave little room for manoeuvre when it comes to introducing elements to condition the sound. But there is always some contribution with the electronics used. Starting from a stable handling, after many hours of testing, the sound glides with great clarity. It is that exposed, crisp, bright and somewhat cool profile that is classic for this new ESS chip. I feel that the XO has an analytical bent to it, where both resolution and definition are squeezed. It is a device that can be very useful for sound monitoring, because it is able to exploit that aspect with the right headphones. The spirit of the XO is strong and this is noticeable even with warm IEMS. And although the SE output is quite good, I’m inclined to use the balanced output, for a more dynamic, clear and detailed sound.
The synergy with the headphones depends on what you are looking for. With analytical IEMS, the sound achieved reaches a clear monitoring level, as I have already mentioned. This is not a pejorative comment, on the contrary, as the neutrality and the level of resolution are very useful when analysing headphones. But, I also enjoy this association very much, when it comes to enjoying rich and unrestricted music. With warm headphones the fit is also remarkable, because the XO is able to bring more light to this profile, adding a new face to the sound of such devices.
As for the lower range, it feels very dynamic, complex, agile and fast. It is a technical range, where the texture is concise, but not very juicy. It is not a smooth bass, but the roughness is felt, but under controlled exposure. In this sense, the bass is not the most descriptive, but if you are looking for definition, a clean presentation, capable of shelling out crisp bass lines and layering, this is one of the most appropriate devices for it. As it could not be otherwise, the punch is dry, but forceful, very well marked and light in its decay. It leaves hardly any aftertaste and the substrate has character. What may be missing in this range is a little more panache, viscerality and passion. Even in the most complex, dirty and uncontrolled passages, the Hidizs XO is able to handle the situation with skill and precision, which is beyond the reach of many audio devices in this range.
The midrange is exaggeratedly clean and neutral. There is not a hint of warmth, nor any influence from the lower range. Through the balanced output the sense of clarity, sharpness, separation, luminosity and definition is exuberant. While this is not a passionate range in the musical sense, it is very remarkable in its technical abilities. The ease with which the XO is able to clothe music in all its complexity is commendable. And this is clearly noticeable in the mid-range. Timbre is genuinely neutral, with a sparkle of brilliance. Detail is exultant, exposed and controlled. There is no room for error, no room for blur, no fuzziness whatsoever. The quality of the midrange will depend on the headphones used, because the XO will be able to bring out the best in them effortlessly. All the richness will be revealed, as well as all the poverty.
On the other hand, this is not a lean midrange, although the sounds are elegantly stylised, there is a tight, dry, but powerful physicality. The body is swift and low-pitched, something that makes the separation of the elements, the level of transparency, as well as the darkness between them, even more evident. In this way, the sense of dynamics is quite high.
Perhaps one of the points to watch out for in this new iteration of ESS’s SoC is the treble. And in the XO, that virtue is outstanding. It is clear that the sound is analytical and clear. But that’s not to say that there’s no control there. The high notes are splashy and crunchy at just the right point. There is a clear maturity in their execution and also in their timbre. They are not overly thin. I feel that the treble is again elegant, spirited and full-bodied enough to avoid being overly piercing or sharp. Their weight is very well calibrated, as is their presentation and exposure. All this makes the sound very easy to follow, highly descriptive. It’s something that persists from the mid-range and re-emerges in the upper range: the music flows very easily. Perhaps not the most musical sound, but a very rich sound, both in its presentation, its level of resolution, its ability to recreate nuances and enrich the music with all its detail, but fully respecting the basis of all the notes. The music is presented in a fully structured way, from the lows to the mids to the highs. The recreation is very precise, consisting of all stages, and the treble crowns the work. Such constructive ability adds a remarkable holographic sensation, as well as a palpable three-dimensional feeling. The level of transparency is clear, the feeling of air is persistent, the image is wide and broad, of good height. The treble adds vapour and volatility. Perhaps the least remarkable point is the depth and a sense of frontal presentation, albeit of great laterality. It is clear that with all the XO’s skill and analytical ability, it is precise in its placement of instruments and is not diffuse in this regard. As I said, it is structurally very competent, although the body and depth suffer slightly, due to the frontal character of the stage recreation.
Finally, the Hidizs XO has two filters, red and blue. Their impact on the music is in the higher regions, so the real impact on the sound will be in the higher harmonics. Difficult to distinguish, I’m leaning towards the red filter.





Hidizs is keen to stand out from the direct competition and has created a very attractive dongle with a high level of construction. It has a pair of buttons (X and O, hence the name), two sound filters and 15 LED lighting modes. Yes, dear reader, you read that right. Because the XO features RGB LED lighting, just like the mechanical gaming keyboards. Clearly, this marketing gimmick may seem superfluous in a world where sound is the star of the show. But together with the balanced output and its power level, it can be a very strong selling point when it comes to choosing one model over another.
For the sound Hidizs has opted for the Sabre Dual ES9219C SoC, the same one that is used in the Hidizs AP80 Pro-X and which has given such good results. It is an analytical profile, with a neutral-bright tendency, which has a high technical level, an excellent descriptive profile, very suitable both for enjoying a very clear, precise, defined and rich sound, as well as for monitoring music. Other great qualities of the XO are the degree of transparency, separation and a great ability to structure the music, giving it three-dimensionality, efficiency and ease of monitoring in all its details.



Earphones and Sources Used During Analysis


  • Hidizs AP80 PRO-X
  • Hidizs AP80 PRO-X Red Copper LE
  • Xiaomi Redmi Note 8 Pro
  • Letshuoer D13
  • Letshuoer S12 Pro
  • TinHiFi P1 MAX Giant Panda
  • TinHiFi T2 DLC
  • Kinera Celest Gumiho
  • Rose QT9 MK2s
  • Hidizs MD4
  • Dunu Titan S
  • Dunu Falcon Pro
  • ISN H40
  • Yanyin Aladdin
  • Penon Globe