Hidizs S3Pro – tiny high-tech USB DAC with MQA

Seems that Hidizs company is on march with the release of new products this year. A whole bunch of USB dongles, DAC/amps and several IEMs. Most of the products have either became a bestseller or joined the leading tribe, at least. The last announcement was S9Pro – more powerful and revised version of S8/S9 type-C ultraportable DAC/amp that won several customer polls in social networks as one of the most balanced / feature-packed options. The passion has not yet subsided while Hidizs has announced S3Pro type-C USB DAC dongle with fresh design and MQA support – which is the topic of our review for today.

What makes S3Pro different in comparison to S9Pro, for instance? Most apparent are: significantly smaller and more handy form factor which is more likely to fit into any pocket and 8x MQA support that was not available in S8/S9/S9Pro dongles. The rest of the features are quite close, some of which are slightly more advanced in older series with only one that would really matter – the output power. Let us remind you that S9 produced 90mW @ SE / 120mW @ BL outputs (for 32Ohms load) while S9Pro has jumped up to 100mW @ SE and 200mW @ BL which is astonishing for such size and has made this dongle one of the mot powerful portable devices. Similarly, S9Pro supports DSD up to 512 and PCM up to 32bit/768kHz. Now, let’s look at new S3Pro specs:

  • DAC: ESS9281C PRO
  • DSD: up to 128
  • PCM: up to 32bit/384kHz
  • MQA: up to 8X unfold (Tidal Masters, HiBy Music, etc)
  • Interface: type-C, USB A converter
  • LED: sampling rate indication
  • Output type: 3.5mm SE, supports in-line remote and mic
    • Output specs:
      • Power: 55mW @ 32Ohms
      • FR: 20Hz – 40kHz
      • SNR: 117dB
      • CH Separation: 70dB
      • THD+N: 0.0008%
  • Size: diameter 20mm, thickness 10mm
  • Weight: 6g
  • Hi-Res audio certified

10% discount for any item at Hidizs store using our promocode: ZMCR10

Hidizs S3Pro is already launched on Kickstarter platform: LINK

Hidizs would also open pre-sale at their product page: LINK

So, the difference in power output is apparent but still much better than in most of the smartphones. 55mW @ 32Ohms is a good figure, almost 2X as much… Anyway, in such comparison between S3Pro and S9Pro we can see very different targeting – one is made for maximum versality + Hi-Res streaming services and the other, more powerful one, to retrieve maximum quality from offline audio collection.

S3Pro packaging and design:

Hidizs S3Pro made its way from China in a perfect state and totally undamaged. The main reason for keeping box shape in a perfect condition during the transportation is that Hidizs used hard plastic box with cardboard outer layer this time.

Besides that, such box can further be used as secure storage case for S3Pro. Outer layer contains all necessary technical/manufacturer data and product graphics at facing side.

Box contents are:

  • S3Pro dongle
  • USB A adapter
  • Warranty card
  • User manual
  • Plastic storage box (i.e. main box)

Not much, no additional clip. Although, the purpose of this device is fully covered by the box contents except for Lightning adapter for iOS users. Peculiar thing is that there is a special Lightning to Type-C adapter cable that Hidizs has developed for iOS and S8/S9/S9Pro dongles but it wouldn’t do any good to S3Pro users since it has integrated Type-C cable. We hope that Hidizs would release Lightning to Type-C adapter in a similar form factor of their Type-C -> USB A to satisfy iPhone fans.

Regarding design and choice of materials: S3Pro is fully made of aluminum, feels sturdy and solid. Our sample has “gun metal” color but there would be some other color options to choose from. Round notches forming concentric circles radiating outward together with sampling rate LED indicator at the center of the top (facing) side are playing the main role in S3Pro design. Reverse side has nothing to catch a glance at while the SE output is located on the edge. The opposing side of the edge is where the integrated 2 core, 60 strands OFC wire comes from and which ends with Type-C connector in aluminum wrap.

Twisted cable is thick enough to last long, additionally equipped with anti-banding protection. And yes, S3Pro is very small, close to a size of one US cent with only the significant thickness showing that we are dealing with tightly packed high-quality element base. Such small dimensions are much easier to fit into a pocket together with a smartphone. No need for additional clip to hang this dongle on your clothes like with S9, for instance. When connected to a smartphone, S3Pro feels more like a regular IEM cable with large aluminum Y-splitter or other design furniture on it, rather than a separate device.

In overall, S3Pro design is great. It is made of durable material, looks great, perfectly crafted, has active multi-color LED that shows sampling rate and it is very small for such sophisticated features.

Device in use:

Similarly to S8/S9 series, this DAC requires type-C interface connection to smartphone or PC and USB-A adapter from the bundle to be able to connect to PCs that are not equipped with type-C USB port. Android-based smartphones require some applications that would implement USB OTG function and force audio stream to pass to S3Pro. Such as HiBy Music app, UAPP, etc. Or streaming services like Tidal with MQA support to use S3Pro as unfolding processor. We have tried all features with Xiaomi Redmi Note 8Pro running Android 10 and HiBy Music V4.1.0 b.5546 and found no problems in the consistency and logics of this device operation. Switching back and forth between different types, containers, quality and formats of tracks, changing volume, reconnecting didn’t cause any issues which means that the current FW is stable and reliable.

Not sure whether any updates would be available in future but what we would really expect from Hidizs is to release ASIO drivers for Windows 10/11 in the nearest future. It would provide more control over the resulting quality when connected to PC. For now, S3Pro is natively recognized by Windows OS as USB DAC, has no apparent audio lag but only allows to use WASAPI transport in such popular audio software as Foobar.

LED identifies sampling rate but when there is nothing being played for more than 5 seconds – S3Pro LED goes off. We would prefer some indication of “standby” state just to know that S3Pro is correctly connected and consumes smartphone battery charge.

As usual, be sure to set the volume in an app to lower level after connecting S3Pro to any device since it might be set to maximum on the first power cycle. Additionally, in order to control volume in DSD over PCM/DSD native modes with HiBy Music app – volume control should be set to “Hardware volume” in Settings->”Volume Mode” and USB device volume control should be unlocked (USB output setting -> USB Audio volume lock -> Unlock).

Now, about the firmware. First of all, S3Pro is a flashback to what was initially introduced in Hidizs Sonata type-C audio cables/dongles – different FW versions for different purposes. But now, instead of different processing paths, S3Pro firmware versions would cover 3 tuning styles. The default one would be “Tonal Balance” whereas other two (treble and bass-oriented) would be available at Hidizs website support section for further manual uploading. (Interesting feature that needs more development from Hidizs: allowing end-users to tune sound to their liking in some dedicated smartphone app that would also allow to push different FW to S3Pro.)

One thing noticed is that S3Pro case heats up noticeably during audio processing and stays ~47C until music is stopped. Perhaps, very tight space inside and aluminum chassis are playing the main role in heat dissipation as a result.


In general, we liked it. We have tested it with different fairly neutral headphones like Hidizs MS1 / MS2, and impedance up to 32Ohm. In such combination and loaded with “balanced” firmware, the output power is quite enough for good driving ability at high volume (half the level). If you go higher than half, noticeable distortions in the sound caused by a lack of power step in – the sound becomes louder, but the quality on treble and midbass begins to suffer. Therefore, we can conclude that there will be no problems with headphones up to ~ 32-50Ohm even in noisy environment. Higher loads are better for enjoying in quiet environments.

Despite the fact that the firmware is balanced, the bass portion is quite pronounced which enlarges stage size and volume. Bass is deep, well-defined and does not overwhelm the rest of the frequencies. Midbass is powerful and dynamic, with excellent attack and moderate pitch – not too sonorous and not ruining the overall impression of tonal balance. Mids are full-bodied, a little thick due to the lower part of the range, which is rather a plus (certainly not dry or flashy thin). Treble is clean, but simplified in detail – sounds accurate and doesn’t hurt with sibilants, but not astonishing in terms of the amount of details. The overall resolution as well as the stage size are average – neither disappointing nor astounding, but quite impressive for a device of this type. Significantly better than a smartphone, but worse than a good DAP in $100-200 price segment.

As a result, the sound is very good, especially considering the main purpose and size of the device. More than enough to deal with Hi-Res streaming services with noticeably better sound quality and drive than from a regular smartphone.


Truthfully, it is a tough decision for us, personally, which device to choose from a whole bunch of “S” series Hidizs type-C DAC/amps. S9 and its Pro version have BL outputs and outstanding ability to drive significant loads. S3Pro is less capable in this respect but offers MQA support for streaming services or offline MQA collection. We think that this choice is more about lifestyle and personal preferences in music. Maximum mobility and constant curiosity in current music trends would definitely be better off with Hidizs S3Pro, whereas S9/S9Pro are more closer to calm, desktop type of use with once established audio taste and music collection. If to consider on its own, S3Pro is a tiny piece of tightly packed and perfectly crafted technology, both software and hardware-wise, that totally does its job, yet delivering much better sound quality than a regular smartphone or PC and driving end headgear much better. With the declared price and features, we think that Hidizs has managed to create another participant for its winner formation.

Hidizs S3Pro is already launched on Kickstarter platform: LINK

10% discount for any item at Hidizs store using our promocode: ZMCR10

Hidizs would also open pre-sale at their product page: LINK

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