Hidizs S3 Pro Review

Hidizs S3 Pro Review

31 December 2021 0 By Petros Laskis

Minimal and competitive

Pros: + Good sound
+ Powerful enough for sensitive earphones
+ Three different sound profiles
+ Very compact and lightweight
+ Quality cable
+ Good build quality
+ Low power consumption
+ PCM 32Bit/384kHz and DSD128

Cons: + Not class leading in technicalities
+ Less power than some of the competition
+ No auto standby mode
+ Calling volume cannot be adjusted
+ The sound tuning firmware is available for Windows 10 only

The Hidizs S3 PRO was kindly provided by HiFiGo free of charge and I only covered import fees and tax.
This is my honest and subjective evaluation of it.
The S3 PRO is available in black and silver at $69 but you can find it as low as $62.
You can use this – non affiliate – link to check the current price and buy.


Introduction and technical specifications

The Hidizs S3 PRO is an ultra Portable Hi-Res, plug and play DAC/amp dongle that supports 8x unfolding of MQA audio, PCM up to 32Bit/384kHz and DSD128.
The DAC chip used is the low power consumption, ultra-low distortion ESS9281C Pro that is commonly used in a lot of similar devices.
Hidizs have gone one step further by adding 4 Panasonic capacitors for an enhanced listening experience.
The power output is rated at 55mW@32Ω.


Three firmware options to tune the sound

The S3 PRO supports three firmware options that offer different sound tunings.
– Transparent treble for bright, clean, crisp, and detailed sound.
– Tonal balance with a pure pleasing sound.
– More prominent bass with incredible elasticity and a phenomenal depth.
These aren’t the usual low pass filters that apply to the time domain and alter the impulse response but rather three different frequency response curves.
The firmware can be installed through a Windows 10 PC only by using the flash tool that can be downloaded from the Hidizs website.
The default firmware is the balanced one.


Physical appearance

The S3 PRO has a small rounded body made from aluminium alloy CNC integrated molding with only 20mm of diameter and 90mm of length with the cable included.
The cable that leads to the USB type C plug is of high quality with a mixed Braiding of 2 core high purity silver + 2 core OFC wires (60 strands each) plus strain reliefs to both ends.
A small LED indicator lights up in different colors, synchronized with the sampling rate of the currently played track:
– Red: 44.1k-48k
– Blue: 88.2k-384k
– Pink: MQA



The S3 PRO is plug’n play compatible with Windows 10, Mac OS, iPad OS, Android, iOS or newer systems.
(For iOS users, the Lightning OTG cable has to be purchased separately)
It is also compatible with the official HiBy Music app that supports both Android & iOS.
The S3 PRO will not pause or enter standby mode when the earphone is disconnected from the device.
Another feature that a lot of users will find convenient is that the S3 PRO supports wire control of playback/pause and volume functions plus phone calls, without having to pull it out from your mobile phone when a call comes in.
Well at least in theory because with my phone I was able to make and receive calls without the need to unplug but the calling volume was set to a fixed level not allowing me to adjust it.
This might be an issue with the specific only phone but I haven’t been able to test with another.
The S3 PRO is mostly immune to electromagnetic interference but at a few rare instances it picked some noise from the mobile antenna.


Sound impressions

Prior to listening tests I left the S3 PRO playing music for about 80 hours.
Sound impressions are with the balanced firmware installed unless noted otherwise.
I have mostly used iems like the FiiO FD3, DUNU Falcon Pro and Final Audio B3 but the S3 PRO is also pretty adequate at running easy to drive headphones like the Sennheiser HD660S, not to their full potential though.


The general impression is that of a linear, balanced sounding DAC with a good factor of engagement where music flows with ease and has a mildly warm presentation with a hint of treble brightness.
The top end is sparkling with plenty of energy, a little bright but not harsh, slightly lacking in ultimate extension but with good overall clarity and detail retrieval.
The treble is transparent and true to the source material but timbre is slightly metallic/artificial with a sense of roughness and a leaner texture that leads to a somewhat rushed decay.
On the other hand the low end is full bodied and weighty while retaining good amounts of technicalities (given the price range) with sufficient layering, tight texture and immense dynamics although clarity and brute force are not on par with the top contenders.
Mid range sounds open and atmospheric with a good sense of separation, the timbre is natural so voices and instruments are presented in a lifelike manner with fine articulation and fluidity in their expression.
The soundstage is spacious with plenty of air around the instruments and precise positioning so the S3 PRO will never be the bottleneck and can certainly do justice to the staging properties of a given earphone.



The method of installing the firmware wouldn’t allow for quick A/B comparisons so for testing I used only two tracks and listened to them with every option back and forth.
The balanced firmware has a linear frequency response leading into the above mentioned impressions.
With the treble firmware I have noticed enhanced top end clarity and sparkle with a more energetic character, a little better detail retrieval but the overall sound signature became brighter.
The bass firmware added a mild mid – bass (mostly) boost giving some extra low end oomph and warmness without mudding the sound too much.
The two non balanced firmware options are quite well executed to offer a fine tuning to the sound and this is the feature that differentiates the S3 PRO from the competition.


In the end

The market is flooded with portable USB DAC dongles which are built around the same chipsets and sound more or less the same.
Given this context the Hidizs S3 PRO sounds equally good without any noticeable flaws but slightly inferior to the category leaders.
In the end the deciding criteria should be mostly focused on form factor and power output.
From this perspective the Hidizs S3 PRO is indeed class leading with ultra compact size and minimal footprint but on the other hand power output is slightly lower than some of the newer products like the iBasso DC05.
However S3 PRO has an ace in the hole, the advantage of the three different sound profiles that is a unique feature among the category making it the best option for people with diverse music tastes and larger collection of earphones.

Test playlist

Copyright – Laskis Petros 2021.