The Hidizs S9 Pro Plus was kindly provided free of charge in exchange for an honest review. I didn’t receive monetary or any other kind of compensation and I don’t use affiliate links.
The pre-order starts November 16th, 9:30AM (EST) and ends November 30th, 9:30AM (EST). There is a special promo for the first 100 purchased units that can be had for $69.99. After that the price is $79.99. Estimated shipping date is December 5th, 2023.
Hidizs was kind enough to offer a special 5% discount for everyone reading this article. Just use the code ICHOS5OFF upon checkout. (I don’t earn any commission)
Hidizs
Hidizs is a well established audiophile brand that focuses on portable audio gear manufacturing. They make digital portable players (DAPs) like the AP80 Pro-x, USB DAC dongles like the XO and numerous IEMs from the entry level MS1 to their current flagship, the MS5.
Hidizs S9 Pro Plus
The S9 Pro Plus is a new USB DAC dongle by Hidizs which is an updated version of the Hidizs S9 Pro thus named “Plus”. Both use a single ESS ES9038Q2M DAC chip in a balanced configuration but the newer model comes with different amplifier op-amps (not disclosed to the public) and tuning.
The S9 Pro Plus is compatible with a wide range of platforms, including Windows, Mac OS, iPad OS, Android, iOS, and Harmony OS thus offering true plug-and-play convenience on all operating systems. Sampling rates supported are PCM up to 32bit/768kHz and native DSD512. For Windows there is also a dedicated ASIO driver available on Hidizs website.
There is some marketing literature on why the S9 Pro Plus was given the nickname “Martha” that you can read here .
User Interface
The Hidizs S9 Pro Plus is a portable DAC dongle with a USB type-C input and both 3.5mm – 4.4mm headphone outputs. It also features two hardware buttons that you can use to adjust the volume and select one of the 7 available digital filters.
The S9 Pro Plus is equipped with a “Hidizs” logo RGB light that will constantly display a color according to the incoming sampling rate. Yellow: DSD 64/128, Purple: DSD 256/512, Blue: PCM 176.4/192, Red: PCM 352.8/384, White: PCM 705.6/768 and Green: PCM 44.1/48/88.2/96.
Using the buttons
A single press of each button will either raise or lower the volume while simultaneously pressing both will change the digital filter. Every time you perform this action the RGB light will display a color to indicate the chosen filter. Green: Anodizing fast roll-off, Red: Linear phase fast roll-off, Blue: Linear phase slow roll-off, Yellow Light: Minimum phase fast roll-off, Purple: Minimum phase slow roll-off and White Light: Hybrid fast roll-off.
The internal volume control of the Hidizs S9 Pro Plus is not independent from the host device. For Android devices you get 15 steps from zero to max while for Windows OS you can set the volume from 0 to 100 but each button press corresponds to 2 steps at a time.
Appearance and build quality
The chassis is made from a single block of aerospace-grade aluminum using advanced CNC machining techniques and is available in three finishes, blue, silver and black. The chassis has a rectangular shape with slightly asymmetric lines that look stylish and help with ergonomics by making it more comfortable to hold and easy to use.
Both the front and back surfaces have an extra, transparent, panel insert that is made from hard plastic. An odd choice by Hidizs who should have opted for hardened glass or just left it plain aluminum because this plastic surface gets easily scratched.
For the S9 Pro Plus, Hidizs has abandoned the 2.5mm plug of the previous model in favor of the more common 4.4mm interface so the size of the chassis was inevitably increased. Despite that, the Hidizs S9 Pro Plus weighs 17g only and measures 55×25×11mm so it is actually the same size as the Hidizs XO.
Power output and noise
The power output is 138mW/32Ω from the 3.5mm plug and 180mW/32Ω from the 4.4mm so it is ideal for driving both earphones and sensitive headphones like the Sivga Luan.
Competition is slightly more powerful, like the FiiO KA3 that features the same DAC chip and can do 240mW/32Ω but still the S9 Pro Plus is not that far behind.
Noise floor is inaudible and I haven’t experienced any EMI issues while using sensitive earphones like the Hidizs MS3.
The power consumption of the is 0.12A/0.64W so more or less the same as similar dongles like the Hidizs S9 Pro (0.13A/0.70W), the Hidizs XO (0.13A/0.70W) or the FiiO KA3 (0.12A/0.64W).
As per usual practice the Hidizs S9 Pro Plus was left playing music for about 80 hours before listening evaluation.
Listening impressions
The Hidizs S9 Pro Plus is one of the least clinical and sterile sounding portable DACs featuring the ES9038Q2M chip. The frequency response is neutral and linear but the S9 Pro Plus doesn’t have the usual tendency to push technicalities to their limits and as a result it doesn’t sound artificial nor bright or analytical.
It has a hint of warmness and a sound signature that is quite musical and engaging. This is still an ESS DAC chip so it does sound transparent, crystal clear and sparkling with a touch of sharpness and plenty of luminosity in the treble while it offers very satisfying detail retrieval for the category.
The bass is weighty but tight and controlled, it is fast, layered and well defined, dynamic and impactful. The mid-range is effortless in its presentation, natural sounding with plenty of colorful harmonies and excellent refinement for the category. The texture is rather full and only gets a bit thinner while rising in the upper mids and treble.
The DAC offers a good deal of timbre realism without much artificiality and digital glare. This is a neutral – natural sounding DAC that pairs well with different types of earphones and is equally enjoyable with a great variety of music selections. The soundstage is open and spacious with good positioning accuracy but it is mostly flat without much depth or holography.
Selected comparisons
The Hidizs S9 Pro Plus has a slightly different tuning than the S9 Pro despite using the same DAC chip. The S9 Pro Plus is a little more organic and natural sounding with a greater amount of timbre realism. It sounds more mature and refined with less digital glare, more engaging mid-range, a smoother top end and weightier bass.
The same kind of sonic differences apply when compared to the FiiO KA3 which is less organic and not that natural sounding. The FiiO KA3 has the edge when it comes to technicalities, overall transparency and clarity while it is also a bit more dynamic and impactful. But it is not as smooth and forgiving as the S9 Pro Plus and is also a little brighter and more aggressive.
Going to the Hidizs XO, which costs the same amount of money, it gets a little more difficult to spot the sonic differences. The XO sounds a little rougher and not as mature or refined as the S9 Pro Plus which has the edge in timbre realism. It is a bit more powerful output but the S9 Pro Plus produces weightier and more impactful bass. The XO has a more sparkling character which is better suited to modern stuff (and gets aligned with its youthful appearance) while the S9 Pro Plus is better for applications where timbre realism and resolution are more valued, like for listening to classical music.
In the end
The Hidizs S9 Pro Plus doesn’t have something new or unique to add in the very saturated market but it holds on its own because it sounds really good and is more lightweight than much of the competition. You can also pick this one because you can fiddle with the digital filters without the need to reach for your phone or simply because you are a die hard fan of Hidizs.
Copyright – Petros Laskis 2023.
+ Neutral and balanced + Realistic timbre + Not too artificial or digital sound + Clear and transparent + Dynamic and impactful + Dead silent without EMI + Plenty of power + Efficient + Hardware buttons + Digital filter selection on the fly + Compact and lightweight - Flat soundstage - Plastic panel inserts - No gain settings - No independent volume control - Less powerful than the competition - No SPDIF digital output
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