Hidizs S3 Pro English Review


In The Small Pot Is The Good Jam




Construction and Design
Packaging and Accessories




  • Excellent size/sound/power/price ratio.
  • Possibility to change the sound profile between 3 modes, using different firmwares.
  • Low weight.
  • MQA X8, TIDAL Masters/HiBy Music/Apple Music compatibility.
  • Technical specifications and remarkable measurements.




  • It does not come with a case for storage and protection.
  • The 3.5mm audio jack is not gold-plated.


Purchase Link




Link to the Store






Hidizs continues to renew and add new devices to its catalogue. Continuing with the DAC/AMP, this time it is a small USB device with 3.5mm audio output. It is made up of a round, metallic tablet containing the audio output, an LED in its centre and a short cable with the USB Type-C connector. It is equipped with a power-efficient ESS ES9281C PRO chip that supports up to 32Bit/384kHz, DSD up to 128 and MQA X8. It is compatible with Windows, Mac OS, iPad OS, Android, iOS, even newer systems. With the S3 Pro it will be possible to fully experience TIDAL Masters, HiBy Music and even the newly released Apple Spatial Audio. It supports headphones with cable and microphone control. Of course, it is Hi-RES certified and weighs approximately 6g. We will now proceed to discuss the rest of the features and virtues.





  • Dimensions: 20x10x90mm.
  • Weight: about 6g.
  • MQA support: x8.
  • Sample rate indicator light.
  • DAC chip: ESS ES9281C PRO.
  • Sampling rate: up to 32Bit/384kHz.
  • DSD support: up to 128.
  • Headphone output: Single-Ended 3.5mm.
  • Total Harmonic Distortion + Noise: 0.0008%.
  • Signal to Noise Ratio: 117dB.
  • Channel Separation: 70dB.
  • Frequency response: 20Hz-40kHz (±0.1dB).
  • Output power: LR 55mW@32Ω.
  • Power connector: USB Type-C.
  • Supports Windows, Mac OS, iPad OS, Android, iOS or newer systems.





The Hidizs S3 Pro comes in a small black box, dimensions 76.5x75x39.5mm. On the front side are some of its features and a realistic photo in its centre. On the back are its complete specifications, in silver lettering. After removing the cardboard sleeve, a black hard plastic box appears, with the Hidizs logo on its lid. Lift it off and the dongle appears encased in a thick black foam mould, protected by a piece of bubble wrap.


The content is as follows:


  • 1 Hidizs S3 Pro.
  • 1 USB-A adapter.
  • 1 Warranty card.
  • 1 User manual.


The packaging is small and fair, as are the contents. Nor is anything else necessary, as these products do not usually have protective cases or boxes.



Construction and Design


The Hidizs S3 Pro is a small, cylindrical, metallic, silver-coloured piece. Its diameter is approximately 21mm and its thickness is 9.7mm. The weight is 6 grams. Its faces are like discs, with concentric grooves. In the centre of one side it says «MQA», plus its logo and on the other side it says «Hidizs S3Pro», all in white letters. On this side, right in the centre, is an LED, the colour of which indicates the sample rate and the type of file being played. On the edge is the 3.5mm SE audio socket, which is made of black plastic. On the other side is the cable output. It is a mixed cable with 4 coiled strands, two of them are made of high purity silver and the other two are made of bright OFC copper. Each strand has 60 wires. The total length of the cable is approximately 47mm, including the sleeves that protect the joints. Finally, there is the USB Type-C connector, whose total length is about 20mm. It comes in a silver sleeve with the brand’s logo. As a complement, there is also a USB Type-C to USB-A adapter, whose total length is about 22mm.
Internally, it has 4 Panasonic capacitors.
The design is simple, but curious, elegant and small. Both the cable and the connectors are quality, lightweight, despite being metallic. The USB adapter matches the quality, colour and size, as does the cable. The only negative point is that the 3.5mm female connector is not gold plated.





The S3 PRO is compatible with Mac OS, iPad OS, Android, iOS or newer systems. It does not come with a Lightning OTG cable, which must be purchased separately. For Windows 10, it is compatible without the need to install additional drivers. It is also compatible with DAPS that support this type of Dongles.
Finally, it is compatible with TIDAL Masters/HiBy Music/Apple Music.





The operation is the usual for this type of device, connect, detect and run. In Windows, when it starts playing, it works with a very fast fade.
The existing LED indicates the sample rate, as follows:


  • Red: 44.1-48kHz
  • Blue: 88.2-384kHz
  • Pink: MQA


As this model has a USB Type-C cable, it can be connected to any device with this connection. In case you need to connect to a traditional USB, you can use the additional USB-A adapter, which comes as an add-on.
Supports headphones with microphone and control. No need to remove it from the smartphone to answer the phone.
3 different types of firmwares can be used, which allow the sound to be modified (according to specifications):


  1. Transparent, bright, clean, crisp and detailed treble.
  2. Tonal balance with a pure and pleasant sound.
  3. More prominent bass with incredible elasticity and phenomenal depth.


Default firmware is firmware 2.

The S3 Pro is Hi-Res Audio Certified.





As usual with Hidizs, their measurements are usually exemplary. As can be seen, the output impedance is very low (less than 1 Ω), as the maximum voltage is almost the same with no load as it is for 33 Ω or 100 Ω.



No load


Maximum no-load voltage exceeds 1.4V, with excellent linearity.



15 Ω


The maximum voltage, without visible distortion, is about 1V, respecting the high linearity. This is just over 66mW. This value is surprising for the size level of the device.



33 Ω


As usual, Hidizs is very cautious in its power measurements. According to mine, the S3 Pro can be used at almost full power without visible distortion, with an impedance of 33Ω. The voltage obtained is almost the same as without load, over 1.4V. That provides more than 59mW. The specifications are 55mW at 32Ω, so it is sure to be met and, in addition, it is sure to offer very low distortion.



100 Ω


With this load connected, the maximum voltage of over 1.4V can be assumed. The result is a power of almost 20mW.



Frequency Response


The frequency response is flat throughout its range (10Hz – 40kHz). The drop at the 40kHz end of the range is very slight, practically negligible. Linearity is observed to be maintained at all volumes and there are no differences in power or linearity between the channels. It can be seen how each channel overlaps, forming a single frequency response line.





With the default firmware, the tuning is the previously numbered 2. I feel that the profile is balanced, the frequency response is flat and I don’t notice any preference towards any band.
Although to say that the sound is mature does not bring much clarity or descriptive ability, I think it is true. Going into detail, this maturity is reflected in all the bands, as they are always within a tonal coherence. There is no hint of peaks or mismatches, just a respect for fidelity, within contained parameters. Let no one expect to find an exuberant sound, completely diaphanous, extensive and open. Nor is it a sparse, narrow, poor or bland representation. The sound of the S3 Pro is serious and convincing, even tenacious. From its power, it is able to handle all kinds of IEMS in an exemplary manner, also thanks to its low output impedance.
Going into more detail and starting, as usual, with the low end, the S3 Pro has a remarkable body in this range, a noticeable sense of punch that brings power to the sound and a more than good resolution. The level of definition is also evident, resulting in a powerful area, with a good sense of clarity, cleanliness and depth. Perhaps it suffers from a greater sensory perception in the sub-bass area, being more evident in the mid-bass, with the consequent (very slight) loss of linearity and realism. All this, when compared to higher priced dongles and from a more perceptual rather than frequency response based point of view.

The representation of the mid-range persists in the idea of tonal balance. In this sense, the timbre comes across as realistic, natural and not at all forced. While the sound is not brilliant with this firmware, the warmth is not representative either, although it does appear slightly. It is worth noting that the level of clarity and separation, which is very important in this range, remains, if not increases. In this way, the distinction between elements, voices and instruments is clear, creating a respectful communion between them all. There are no predominant voices, no prominent instruments, but only what the music decides, or the connected earphones favour. The profile is neither analytical, nor completely silky. It is not a fully profiled sound or one of extreme resolution. It’s a good middle ground, gentle, enjoying a little softness and a little definition, but not predominantly. So, without realising it and going back to the description of the sound profile (by Hidizs), the words of tonal balance, purity and pleasant feeling are highly eloquent and accurate. And this is something that in the mid-range is manifestly very clear. And I would not like to forget an eminent sense of musicality in the middle section.
Coming to the high end, the treble is pleasant and natural in its representation. There are no jolts, peaks or exceptions that upset the balance of the sound. Their level of definition veers to the fair but attractive side, with a tendency towards smoothness rather than crispness or brightness. The clarity is diaphanous and the level of resolution quite adequate, to maintain a sound with transparency, openness and air.
The scene has an eminently wide representation, with good depth and average height. The level of three-dimensionality is not very remarkable, although the sound escapes a flat or lifeless feeling, it is certainly more than that. Still, the level of detail is in keeping with the product. Hidden nuances and micro details are perceived as somewhat distant, slightly buried. It is not a revelatory sound, perhaps more because of the smoothness of the profile and its level of cohesion. In this sense, the separation, although quite good, doesn’t quite reach a complete dark background, giving the sound a higher transparency than it has. In fact, the S3 Pro is quite honest in this respect and still good enough to be very satisfied with it.





The new Hidizs S3 Pro is one of the smallest and lightest devices, which supports MQA X8. It is also very powerful, has low power consumption and is future-proof, as it is highly compatible with a multitude of systems. Its price is reasonable and its measures, as usual with Hidizs, are very good. In addition, its sound is remarkable and can be changed to taste, as, depending on the firmware installed, the profile can vary between 3 modes. It is extremely difficult to find all these virtues in a device like this and at this price, that is why its quality/price ratio is great. Can anyone give more?



Earphones and Sources Used During Analysis


  • HiBy R3 Pro
  • Xiaomi Redmi Note 8 Pro
  • NiceHCK Lofty
  • Rose QT9 MKII
  • Hidizs MS2
  • ISN H40
  • NS Audio NS5 MKII Extra Bass
  • Ikko OH10
  • Reecho SG-03
  • Shozy Neo BG
  • Smabat M0
  • NiceHCK EBX21
  • Takstar Pro 80