Hidizs S9Pro – more power, more drive

About a week ago Hidizs has announced the launch of a successor to its highly popular balanced S9 USB DAC/amp that is already on pre-order state. We have reviewed the original S9 some time ago and defined it as highly recommended for those who want to upgrade smartphone/tablet/laptop sound and squeeze out much more juice from music quality.

New version gets PRO suffix due to some significant changes in HW that increases output power and improves other characteristics of this small but mighty device. While the exterior left untouched, main differences are hidden under the hood and here is the table that compares all generations of “S” series units:

This table discloses the main improvements and changes in new S9Pro. For us, the most important is the output power that has increased from 90 to 100mW @ 3.5mm SE output and from 120 to 200 mW @ 2.5mm BL output. Hell lot of additional power on balanced port. Not sure how Hidizs has managed to do that while maintaining similarly small package. Perhaps, shifting from AKK5593EQ to ESS9038Q2M made it possible and also improved other sound spec-related values. For now, it seems that S9Pro is one of the most powerful USB stick-type of DAC that doesn’t rely on its own battery. Just think – it is more powerful than AP80Pro (190mW on 2.5mm BL) with larger dimensions and LiON battery inside which is completely enough to drive 150Ohms overheads…

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

Hidizs S9Pro on pre-order (20% OFF): LINK

Anyway, now about S9Pro full specs:

What we have noticed just now is that specs declare that S9Pro is compatible with mic equipped earphones. Good to know that when such device is connected to a smartphone you would still have a possibility to accept calls and have a conversation without switching to internal phone mic or loudspeaker. Although, we would still check how can it be possible when S9Pro is occupied by something like HiBy Music app in exclusive USB audio mode. Usually, such mode won’t let other sounds from the system mixer to pass through… Not enabling this mode would solve such problem but the sound might be affected by the system processing. We would give our feedback on this further in this text.

Packaging and design:

Nothing much has changed in terms of packaging. It is still logistic-friendly small matt black box but instead of silver outlines new box has glossy product picture on the facing side. Box is stiff and comes undamaged after a long trip from China to other parts of the world. Internal box structure consists of two compartments where the device is located on top in a special soft insert and all accessories are stored underneath. Contents are:

  • S9Pro DAC/amp
  • transparent plastic holder / clip
  • USB type C -> USB type C cable (65см)
  • USB type C -> USB type C cable (15см)
  • USB type C -> USB A adapter
  • leaflets, cards…

Design of this unit has not changed either, therefore we would comment ourselves next:

S9Pro is a small unit (close to AA battery size) but still shows quite complicated design. It’s shell is made of aluminum (CNC) whereas both front and back sides are covered with glass panels. Such approach is inherited from other Hidizs products and resembles the design principles of this brand.

Personally, we like such approach which adds the value to the device in terms of overall feel. In fact, S9Pro feels very solid and durable while looking pretty for its combination of aluminum and glass. There are no buttons and no screen, side edges are left free of any elements. USB type-C port is located at the bottom edge and both SE & Balanced ports are situated one over the other on the thickest part of the shell — its top edge.

The only indication that S9Pro has on board is represented by semi transparent Hidizs logo under the front glass panel. Not only it gets lit upon incoming power supply, but also its colors are synchronized with the sampling rates of played tracks.

Plastic clip / holder that comes as a part of the bundle is really great accessory. It securely holds S9Pro at place, protects it from physical impacts and allows to attach it to clothes. It doesn’t limit the connectivity or usability of this device. Both short and long cables are similar — soft and flexible transparent braid, aluminum type-C connectors and banding protection at both sides. USB type-C -> USB A adapter is applicable whenever someone wants to connect to laptop or PC.

Device in use:

Since S9Pro has type-C to USB A adapter along with type-C cables – we can try it with laptop/PC as well, not only with Android smartphone. In case of a smartphone everything is straight forward: use type-C to type-C cable to connect devices, HiBy Music App to send audio data over USB. S9Pro gets recognized as USB DAC and there are no problems whatsoever. S9 LED color would resemble track quality:

  • Yellow: DSD64/128
  • Purple: DSD256/512
  • Blue: PCM176.4/192KHz
  • Red: PCM 352.8/384KHz
  • White: PCM 705.6/768KHz
  • Green: PCM 44.1/48/88.2/96KHz

The only small inconvenience here is the absence of control buttons on S9Pro. Volume is being regulated on a smartphone for USB device and might be at its maximum upon initial connection. It might be harmful for sensitive, low impedance IEMs. So, just keep in mind to set the appropriate volume level after connecting S9Pro to smartphone before hitting playback.

In case of Windows 10 laptop/PC – S9Pro gets natively supported as USB DAC but there would be a dedicated ASIO driver that was announced by Hidizs and should become available for download a bit later. Initial S9 already has this driver and S9Pro is on the waiting list. ASIO drivers would give the most sound quality while native Windows 10 driver would have the lowest audio lag possible.

S9Pro shell gets warm during operation but not much, around 32C with SE output and 37C with BL output.


Tested with Xiaomi Redmi Note 8Pro, Lenovo Y500, Hidizs MS2 SE and Hidizs MS2 BE, Audio-Technica ATH-M50.

Repeating the success of its predecessor, S9Pro can easily be compared to best representatives of entry level DAPs — significantly better than vast majority of smartphones with their weak sound output and similarly better than even most of the laptops. Smartphones can’t perform with such clarity, can’t retreive this much resolution and its dynamics lacks power.

S9Pro is much better in resolving lower range, retrieving good amount of textures and its mid bass performance is way ahead. Extension of the lower end gets increased, lows gain in clarity and give a feeling of volume. It is much better separated from mids. Although, lower end is is not accented in S9Pro and this unit definitely not tending to dark signature.

Resolution on mids is somewhere close to AP80Pro DAP, maybe slightly less obvious… Slight tendency to bright delivery is present, making a bit more accent on female over male vocals. Still male voices sound pretty thick and natural. Great amount of details retrieved from upper mid range. S9Pro on mids is definitely sounding more transparent and rich than muddy and mixed result of the same track coming from a smartphone.

Treble is also handled much better, it is more clear, crisp and airy. Extension is greatly increased, making the entire sound picture brighter and detailed on the upper end. Small amount of sibilance is present with some sensitive IEMs but absent with overheads. In general, this range is accurate and in a good balance with mids and bass.

Similarly to S9, Pro version can greatly improve every aspect of the sound on a smartphone or laptop that don’t feature dedicated, good quality DAC. Both devices sounds more natural and at the same time deliver more details with better extensions and stronger dynamics. This goes to both output types, while 2.5mm BL is twice as powerful – making stage slightly wider and instrument separation slightly better.

Finally, yes – we have check whether HiBy Music app would allow other sounds to pass to USB device in USB exclusive mode: no, it won’t let it pass. Therefore, in order to use mic and talk over S9Pro – USB exclusive mode is not used and audio quality might get worse due to Android OS mixer being used.

Compared to Hidizs S9:

S9 and S9Pro have common exteriors, similar philosophy, compatibility and features. Although, sounding slightly different. Since S9Pro has significantly more powerful 2.5mm BL output – it has better drive and dynamics that results in more punchy mid bass. Slightly more bright and colder picturing makes upper end more detailed and crisp. Instrument separation seems to be slightly better and stage a bit wider. At the same time, S9 is still a good unit since it is thicker on mids and tends more towards lows.

Compared to Hilidac Beam 2:

The main advantage of Beam 2 is MQA support (if you are still not disappointed with it). It has slightly more power on BL output but doesn’t support this much of PCM or DSD as S9Pro does. Sounds pretty much similar, with slightly wider stage but more prone to sibilance and even brighter. The main disadvantages: more expensive and both outputs are located on the side which makes it less convenient to store in a pocket.


With the release of the initial S9, Hidizs has proven than even a small power-dependent USB DAC can be powerful enough and sound as good as most of the entry-level DAPs. Now the successor, S9Pro – sets the new standards on the market for such tiny audio companions in terms of maximum output power and driving ability as a consequence. This also results in unexpectedly reach sound, large amount of textures and details, good extensions at both ends, sufficient dynamics and enlarged stage. All of that produced by a small unit, enclosed to durable aluminum chassis that does not require charging and doesn’t weight anything… Perfect and small, with large sound!

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

Hidizs S9Pro on pre-order (20% OFF): LINK

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