HIDIZS S9 PRO PLUS: MARTHA

Inclusions in the box:
Dongle itself
Type C to C Cable
Type C to A Adapter
2 Hi-Res Stickers
Hidizs Warranty Card

The Martha does not have the typical ESS implementation. Instead of being neutral-bright or a bright piece, this is more of a warm-neutral dongle with a slight boost in subbass, slightly forward vocals and smooth treble. The bass has a prominent presentation. There is a subtle subbass improvement with the "rumbling" being slightly more identifiable. It is fast and punchy, but without being too dark. Additionally, it has a well-laid robust and organic bass response. It is a solid choice for those wishing for that deep, rumbly male vocal(for example, that of Geoff Castelluci).

The mids have a more forward presentation. It is nicely detailed with a thicker and more refined texture. It has that "lush" sort of presentation for vocals, giving the notes therein a heavier yet still vibrant presentation. Lastly, there is clarity without being aggressive.

The treble region is resolving as well, with a slightly smoother presentation. It is not harsh. There is a "smooth extension" in just the right amount(at least in my standards). It is well-defined, has great control, and has a good amount of "air". Futhermore, it has a controlled presentation giving the user a sense of listening to a clean, crisp and transparent sound.

Comparisons:
VS DC03 Pro: Martha has better bass presentation and more forward mids. It also has a warmer tonality overall, while the DC03 Pro has a more airy treble presentation with it being identifiably brighter than the Martha.

Additional Notes:

In my opinion, this dongle is for those who want a warm-neutral and lush presentation, wishing for a slightly tamer treble(yep, imo not for trebleheads) without loosing details.

Just a note that contrary to the specs on "paper" where it doesn't have that much output power, I have fair reason to believe that the 138mW for SE and 180mW for Balanced is a very conservative approximation of how much power it can dish out. Thank you for spending time reading my review of the S9 Pro Plus Martha, have a good day.

Used: Poco M3 Pro 5G with the S9 Pro Plus Martha
Music App used: UAPP and HiBy Music Player(no equalizer used for both)

Songs/Tracks heavily used(in alphabetical order):
214-Rivermaya(16bit/44.1kHz)
A Homesick Song from the Frontier-Zhang Yongyan(24bit/96kHz)
Again & Again-Plastic Memories(24bit/48kHz)
Akatsuki no Requiem-Linked Horizon(16bit/44.1kHz)
Akuma no Ko-Ai Higuchi(16bt/44.1kHz)
Beat It-Michael Jackson(24bit/96kHz)
Black Sand-Tiny Island(DSD 1bit/2.8MHz)
Blurred Lines-Robin Thicke(16bit/44.1kHz)
Caesura of Despair-Irys(24bit/48kHz)
Deniere Danse-Indila(16bit/44.1kHz)
Down with the Sickness-Disturbed(24bit/96kHz)
Hall of Fame-The Script(24bit/44.1kHz)
Hero's Come Back-nobodyknows+(16bit/44.1kHz)
I Love You Too Much-Diego Luna(16bit/44.1kHz)
In da Club-50 Cent(16bit/44.1kHz)
King-Lauren Aquilina(16bit/44.1kHz)
King Chu dons His Armor-Zhang Hong Yan(24bit/96kHz)
Limbo-Freddie Dredd(16bit/44.1kHz)
Rainbow-South Border(16bit/44.1kHz)
Raining in Manila-Lola Amour(24bit/96kHz)

Additional Tracks:
A Fool for You – Carmen Gomes(DSD 1bit/11.2MHz)
Ashokan Farewell – John R. Burr & Mads Tolling(DSD 1bit/11.2MHz)
Carmen: Suite-Intermezzo – Musicus Orchestra(24bt/192kHz)
Dash-Naomi Shirai(DSD 1bit/11.2MHz)'
Entr'acte-Mai Fukui(DSD 1bit/11.2MHz)
Falling Snowflakes Dotting the Verdant Trees(24bit/176.4kHz)
Meu Amor me du um Lenco(24bit/96kHz)
Ploca Plantor – Out of Time and Country(24bit/176.4kHz)
Prune Flowers(24bit/176.4kHz)
Short People – Newman(DSD 1bit/5.6MHz)
Trace of Grace – Michel Gochard, Swallow, Murgia, Paccoud, Helstoffer(DSD 1bit/11.2MHz)

For those curious, here is the non-afiliated link:
https://www.hidizs.net/products/hidizs-s9-pro-plus-martha-hifi-balanced-dongle-dac
The dongle is currently priced at $89(US) or roughly ₱5000.

HIDIZS S9 PRO+ MARTHA
[ES9038Q2M][139$ USD]

S9 PRO + Technical Buff = S9 PRO PLUS? And Martha is back?

[MY PERSONAL HEAD-FI GRADING]
1 ★ - Appalling! please avoid this!
2 ★★ Subpar offering, there are better options out there!
3 ★★★ Decent with some caveats! Not a bad pick!
4 ★★★★ Not perfect but solid choice ! This should be in your shortlist. A nice addition to your collection.
5 ★★★★★ One the best in class! You should go right ahead & buy one! A must have!

HIDIZS S9 PRO+ MARTHA 3 ★★★​

SOUND IMPRESSIONS & USER EXPERIENCE:
[SOUND QUALITY 7/10 VALUE: 4/10] [NEUTRAL-BRIGHT]

▓▒░ SOUND-SIGNATURE ░▒▓
- Neutral bright with a sub-bass boost. Quite cold in tonality. It gives off an intimate presentation with the bass, mids and treble having nigh equal forwardness within the tri-frequency band.

▓▒░ BASS/LOW-END ░▒▓
- It's got a fast, clean, tight response with a sub-bass oriented character. The overall bassline has this cold and analytical demeanour to its approach.

- The well-extended sub-bass offers great presence and texture. The sub-bass kick is punchy while rumbling effect has good amount of pressure and sustain. The ambience level is decent to keep things atmospheric but the elements of reverb and echo are not well defined.

- Sadly, the mid-bass is on the lean side. There is not much emphasis here. The attack is soft and not much depth to the hits. And in terms of warmth or body it is quite lacking. The ghetto bass replay is bouncy enough with zero bleed onto the lower mid-range.

▓▒░ MID-RANGE /VOCAL ░▒▓
- Overall, the mid-range/vocals are rather forward in the mix. The vocal reproduction has good clarity and transparency at the expends of fullness and richness. The lower harmonics just don’t provide enough warmth and body to the lower mid-range. Hence, there is a hint of dryness on vocal transient, especially on male vocal.

- It just lacks a touch of sweetness and euphony on vocal replay as it sounds more analytical than musical. And the lack of reverb overtone on vocals doesn’t help either. Some of would deem its mid-range to be abit flat or soulless, void of emotion. And it couldn’t be further than the truth. The coldness of the bassline and the brightness of the treble really put a toll on the tonality of its mid-range.

- The same true can be said with its instrument replay, they sound crisp but lacking note-weight and not very dynamic. Having said that, despite its monitoring nature, there hasn’t been any grain or harshness issue is heard.


▓▒░ TREBLE/HIGHS ░▒▓
- Regardless of filter-mode you’re in, the treble is on the bright side but not in the best possible manner. It is not piercing or peaky by any means. There is a good amount of crisp to the notes but they sound rather dry and flat with a hint of metallic edge. It can sound almost shrill or brittle depending on gears. Hence, affecting the naturalness of timbre. There is not much weight to the notes.
- The dynamic can sound quite compressed here as everything just sounds equally loud. The transient could use with a wider range of attack. Constant hi-hats and cymbal crush are more to the fore and tends to linger a little too long which can cause fatigue. While synthetic noise such as electronics, the zinging or shimmering will not have the most satisfying replay.

- The dryness is really something else to appoint that it dries my eardrum. Even on a dark set like my EJ07 or EST112 (loan), I am struggling to listen to them for a longer period of time which is not a very good sign. The bassline is largely responsible for this as there is not enough warmth & moisture to counter balance the brightness and the dryness of the highs.

- At the very least, the clarity and transparency is there to backed it up. The air extension is adequate which gives a nice sense of openness to the stage. There is no unwanted resonance with almost zero issue with sibilance.

- The treble overall sounds very clean. It’s got none of those grains, haze, distortion or any sort of dirty noise which is great. Sure, it’s got its strength but that “dryness” I mentioned earlier is not going to work in everyone’s favor. Those treble sensitive folks and timbre-heads might want to take note.


✧ ════ •TECHNICAL PERFORMANCE• ════ ✧
- The SOUND-FIELD is quite wide, giving an out of ears experience. From an intimate perspective, it’s offer good depth and adequate head-room.

- In terms of IMAGING PROWESS. It’s quite competent. Instrument positioning is sharp and accurate while transition of sound between channel is smooth and clean.

- It’s SEPARATION & LAYERING process is quite competent and it is mostly consistent. Doesn’t seem to struggle all that much on a chaotic passage. Due to the treble being abit hazy, the background is not the blackest. But its forgivable.

- DETAIL-HANDLING, be it macro or micro are well done. I don’t find it to be that inferior versus its competitors.

- As for the DYNAMICS, it’s a mix-bag. Depending on your playlist it can either be compressed or expand. Most of the time, it’s offers good balance between being energetic and laid-back.

- The TONE AND TIMBRE proved to be the S9PRO+ Achilles’ heels in its pursuit of chasing higher fidelity. One of the biggest let-downs is that constant dryness issue. The other thing is the note-weight is abit lacking. And the reverb overtones are not well received thanks to the quick decay and release. All that add up took a huge toll on its musicality. In other words, the sound it produces is not very pleasant.

- The device is WELL BUILT. It is small, light and seems durable.

- The DRIVING POWER is average at best. The AMP on both SE and BAL is more than enough for most IEMs but might struggle on more demanding headphones. The power delivery is HISS-FREE with abit of CLIPPING NOISE when changing tracks.
- Unfortunately the POWER-DRAW is not that efficient. It is quite power hungry. But it is not detrimental.

- As for HEAT-MANAGEMENT is very good. It is not that hot on longer usage.

- Speaking of FEATURES, it does not offer an independent volume control. The increment of volume per steps is not many but it is not that powerful so, it is more than usable. The gain is fixed, as I don’t see any gain-switch on user’s manual. Thankfully, it does provide a 6-ways of digital filters which gives a very subtle change to your music. Its very easy to operate. Not a bad feature.

- As for SYNERGY, it is best to pair the S9PRO+ with a warm and less technical gears. Due to it’s sound profile, it is not a very versatile DAC.

- For 139USD retailed, it is not very well priced. There are much better offerings for half the PRICE. But it does go on sales quite often for around 89USD.


~ HEAD-2-HEAD : IN-DEPTH COMPARISON ~

VS TANCHJIM SPACE [DUAL-CS43131] x BAT AUDIO OTG
[SOUND QUALITY 8/10 VALUE: 8/10] [NEUTRAL-BRIGHT]

"My nearly 1 year old Tanchjim SPACE OTG connectors has gone loose. Hence, I’m using an aftermarket OTG during the test which may alter the sound by 5% at best."

● They both went for a neutral-bright tuning with minimal sound colouration. But the SPACE has a hint of organic touch that makes its sounds more natural.

● The low-end of the S9PRO+ has a greater presence overall. One of the major differences is the SPACE will have a slight mid-bass biased while the S9PRO+ is a more sub-bass oriented. As a result, the sub-bass punch, rumble and grumble has higher pressure and texture. The SPACE mid-bass on the other hand has more meat. It has better extension and hits deeper with longer, more precise decay. The SPACE bassline offers more natural response which prove to have positive effects on its upper harmonics.

● The SPACE will come across as the more mid-centric of the two. The bass and treble elements took a slight step back giving the mids/vocal more room. However, it doesn’t sound as intimate as the S9PRO+. And the vocals on the S9PRO+ has slightly better transparency as well. The voice just carries more nuances. However, the reproduction of vocals on SPACE has more solid fundamental grounds. It carries more body and weight without losing much clarity. It sounds sweeter and more soulful by comparison. It managed to strike the right balance between euphony and clarity which makes it sounds the more natural of the two. Instrument-replay such as strings, guitar, piano and flute seems to have equally good performance.

● The SPACE treble response is certainly bright but perhaps not as bright or dry or as forward as the S9PRO+. The treble response is much more pleasant with the SPACE. In actuality, the treble of the SPACE has slightly more sparkle up top but for some reason it doesn’t dry up your eardrums like the S9PRO+ did. Constant hi-hats and cymbals aren’t as fatiguing with a more precise decay. While electronic zing has a nicer ring to them. Treble sensitive folks will have a better experience with the SPACE. It just has the right balance of bite, edge and crispiness without being too aggressive or soft which can make a treble lover rejoice. And this effect is pretty much consistent across all gears I’ve tried including their very own Hidizs MP145. I find the SPACE’s treble to be well defined yet refine.

As for technical performance:
● The SPACE sounds less intimate; not as wide but offers more depth and head-room in return.

● The blacker background of the S9PRO+ helps in giving it’s separated elements a clearer cut. Giving the S9PRO+ a slight advantage on separation and layering.

● Imaging/instrument placement is slightly sharper with the S9PRO+.

● MICRO-DETAIL with go to the S9PRO by a slight margin, as for DYNAMIC-RANGE, they trade blows.

● One thing that the SPACE does way better than the S9PRO is when it comes to TONE & TIMBRE. Other it’s denser note-weight, it is better at retrieving those elements of reverb on vocal and instrument. It’s got a believable transient attack with more precise decay and better level of sustain. Hence the notes often sound more complete from end to end with the SPACE.

● Next to the S9PRO+, the SPACE is more versatile when it comes to SYNERGY. Still, it is best to pair with warmer, darker gears.

● The SPACE has greater DRIVING POWER with better POWER/VOLUME MANAGEMENT. It’s got gain-switch and independent volume control unlike the S9PRO+.

● The SPACE seems to be more efficient on power-draw but slightly heavier and hotter upon usage.

● The SPACE cost only 89.99 USD retailed. It is nearly 40% cheaper which presents great value vs the S9PRO+ (139USD).

With my money, I’ll still go with the Tanchjim SPACE, it may not be as technical as the S9PRO+ but it does a lot of things more correctly. The more natural timbre of the SPACE is what gravitates me towards it more than S9PRO+



◤FINAL THOUGHTS◢
The Hidizs S9PRO+ then is by no means a terrible dongle. Unfortunately, on the pursuit of chasing higher fidelity, its started to lose sight of what is important which is the naturalness of tone and timbre. It does not need to achieve a 10/10 score on timbral accuracy, it only needs to sound natural enough to our ears. And it didn’t quite do that well. Sure, Hi-RES sound will definitely impress you on short-blast but on longer sessions, the naturalness of tone and timbre will play a bigger role. Once you notice that off-timbre, you just cannot go unnoticed. I find it quite hard to recommend to people especially with that 139$USD price-tag. Even on a 50% discount, it’s hard for me to vouch. I recently reviewed the COLORFLY CDA M1P, I do prefer that quite abit. Preference aside, I’m sorry Hidizs, you have to do better than this. Competitions are tough these days!

========================================================================
【SOURCE & GEARS】

● Native FLAC Files [44.1Khz 16bits-96Khz 24bits]​

● Foobar2000 [ROG Laptop] [Ugreen USB C Adapter]
● Huawei P20 PRO [Phone][ App- Foobar2000]

● IEMS USED FOR ASSESSMENT :
- Letshouer EJ07 x Hakugei Skyrim x Spinfit CP155 (M)
- Dunu EST112 x StarPicker Uranus Super Fusion x Spinfit CP100 (M)
- Tanchjim PRISM x Hakugei Rapheal 2023 x Spinfit CP100 (M)
- 7hz Timeless x Kinera Leyding x Spinfit CP100 (M)
- Hidiz MP145 + Rose-Gold Nozzle x No-Brand 2 Flange.
========================================================================

【PLAYLIST／TEST-TRACKS】​

1977 Fleetwood Mac - Dreams ★
1982 Chicago – Hard to say I'm sorry. ★
2003 NARUTO Original Soundtrack I – Wakiagaru Toushi ★
2008 K.will (케이윌) – 소원 (Great King Sejong OST Part.1)
2009 Maksim – Exodus
2010 Ichiban Ushiro no Daimaou (OST) – Kokoro no Oku De Ha
2014 Grabbitz – Here with you now. ★
2014 BoA – MASAYUME CHASING
2014 Hyolyn – 안녕 Good bye ★
2015 KOKIA – I Found You ★
2015 K MISSING KINGS (OST) - New Kings
2016 K RETURN OF KINGS (OST) - Return of Kings
2016 K RETURN OF KINGS (OST) - If you die.
2017 Berry Goodman – Zutto (ずっと) ★
2017 SawanoHiroyuki[nZk]:mizuki – ViEW
2017 Namie Amuro – Hope
2019 K SEVEN STORIES (OST) - In Pursuit Of
2019 K SEVEN STORIES (OST) - Lost Small World
2019 Blade & Soul (OST) – Half-Moon Lake
2019 CAROLE & TUESDAY VOCAL COLLECTION Vol.1 – Light a Fire ★
2020 Paradox Live Opening Show (1st E.P) – BAE – BaNG!!! ★
2020 Paradox Live Opening Show (1st E.P) – cozmez – Where They At ★
2020 倖田來未 (Kumi Koda) – GET NAKED (Kiyoshi Sugo Remix)
2020 倖田來未 (Kumi Koda) – again (MATZ Remix)
2020 premiere fleurs – プリンシパル
2020 Love Live! Nijigasaki – 朝香果林 (Karin Asaka) – VIVID WORLD ★
2020 Fujii Kaze – へでもねーよ”／Hedemo Ne-YoSeishun Sick
2020 King Gnu – 三文小説 ／Sanmon Shosetsu ★
2021 OWV – Fifth Season ★
2021 加藤 ミリヤ (Miliyah) feat. Yoshida Brothers – この夢が醒めるまで ★
2021 Aoi Teshima – ただいま★
2021 Official髭男dism – Cry Baby
2021 Chanmin BIJIN 美人 – Morning Mood
2021 門脇更紗 (Sarasa Kadowaki) – きれいだ
2021 Mirei Touyama – 美忘録
2021 SELECTION PROJECT Vol.1 – Only one yell -天沢灯ソロver.- ★
2022 Belle (Original Motion Picture Soundtrack) – Million Miles Away (ENG vers.)
2022 rei (E-girls) – Dark Hero.
2022 rei (E-girls) – IDNY
2022 I can fly (Special Edition) – Bleecker Chrome - You will shine ★
2022 I can fly (Special Edition) – YOSHIKI EZAKI x Bleecker Chrome - UP ★
2022 BEAST TAMER (OST) – じんわり感じている幸せ
2022 Ado – 会いたくて
2022 Ado – 踊
2023 La prière – Sweet Dreams ★
2023 Bungou Stray Dogs 4th Season ED – Luck Life – しるし★
2023 Genjitsu no Yohane – Far far away
2023 Genjitsu no Yohane – Hey, dear my friends
2023 UMAMUSUME PRETTY DERBY - Hat on your Head!
2023 Anna – 花のように (Hana no You ni)
2023 riria. – 貴方の側に (Anata no Soba ni)
2024 Dungeon Meshi OP – BUMP OF CHICKEN – Sleep Walking Orchestra ★
2024 Sasaki and Peeps OP – MADKID – FLY
2024 Burn the Witch #0.8 Theme Song – NIL – PROVE

★ Main-Test-Tracks/ A glimpse of what listen to 90% of the of time.


Do take my words for what it’s worth. Afterall, I am just one man. ╮(╯▽╰)╭

THANK YOU SO MUCH FOR READING! HAVE A GOOD DAY WHEREVER YOU ARE! TAKE CARE!

Disclaimer:
- This is a loaner unit. Big thanks to the @ Hidizs Tour Malaysia (Facebook) for making this possible!
Non-Affiliate Link:
https://www.hidizs.net/

EXTRA PHOTOS

It’s been over a year since the release of the Hidizs S9 Pro, so it was high time for Hidizs to release a successor.

Enter the S9 Pro Plus, the latest dongle from Hidizs that neatly fills that gap for a “revision.” The older S9 Pro gets a decent price cut, and the even older S9 gets discontinued. So you get last year’s higher priced model for cheap, while those looking for the latest and the greatest have to spend a bit more.

Fair enough, I guess, but are the upgrades worth the extra bucks, or is it wiser to go for the cheaper, older model? Let’s find out.

This review originally appeared on Headphonesty. Hidizs sent out the unit for review.

Design and Build​

The S9 Pro Plus goes for an aluminum and glass build, with glass on the top and bottom of the device. The design language is similar to Hidizs DAPs with the angular shape and sharp corners.

These glass panels add to the dongle’s overall “premium” feel. However, I am worried about the glass shattering after a fall – something time shall tell.



A new addition is the volume buttons, which also aid in switching between filters. An RGB LED is hidden underneath the Hidizs logo to indicate the sample rate and selected filter. Sadly, the buttons wobble, which is an issue for me.

Finally, there are the ports. The type-C port is on one end of the S9 Pro Plus, while the other end houses the 3.5mm single-ended and 4.4mm balanced ports. The 4.4mm port is another change from the S9 Pro, which has a (less common) 2.5mm port.

Handling​

At 55×25×11mm and 17g, the Hidizs S9 Pro Plus is very easy to carry around in my pocket. It also does not get noticeably warm during operation – so brownie points for that.

Power consumption​

Even when using the balanced output, the power consumption is not out of the ordinary for a dongle of this class. Hidizs has properly optimized the Sabre chipset.

Controls​

The two buttons are the only controls available on the S9 Pro Plus. During playback, they act as volume buttons. When the playback is stopped, simultaneously pressing both buttons changes between the available filters. The filters are as follows:

• Fast roll-off
• Linear-phase fast roll-off
• Minimum phase fast roll-off
• Slow roll-off
• Linear-phase slow roll-off
• Hybrid fast roll-off

App​

Unfortunately, no app is available for the Hidizs S9 Pro Plus, so further customization is out of the equation. I had to use a custom firmware updater by Hiby (a Windows application) for firmware upgrades.

Under the Hood​

The Hidizs S9 Pro Plus utilizes an ESS Sabre ES9038Q2M chipset. This DAC chip is inherently balanced (with two differential DAC chips, one per channel), so it is a popular choice for manufacturers due to its relatively straightforward implementation.

The amp section is not explained in the spec sheet of the S9 Pro Plus. We only get to know the output power for a 32 ohm load (138mW SE, 180mW balanced), and that’s about it.

There is also no dedicated line-out feature, albeit I suspect that by maxing out the volume on the hardware level, you should achieve 2Vrms and 4Vrms outputs, respectively, on the single-ended and balanced outputs.

How Does the Hidizs S9 Pro Plus Sound?​

I used the Hidizs S9 Pro Plus with a range of devices, including smartphones (Pixel 4 XL, Galaxy S23), tablets (Fire Max 11), and laptops (Apple M1 Macbook Pro, Microsoft Surface Laptop 4).

Ideally, sources should be “transparent,” with no inherent coloration. Reality is far from perfection, though, so you’ll find that some sources can lean a bit warm while others may sound brighter. The Hidizs S9 Pro Plus is mostly neutral in tone, with a slight hint of warmth, courtesy of rounded bass notes.

In terms of amplification ability, the majority of the IEMs are easily driven. Only when it comes to very tricky loads the S9 Pro Plus falters. For example, the Final E5000 (92 dB/mW @14 ohms, with lower sensitivity in the bass region) or the Tin P1 Plus (highly inefficient magnet array).

On the other end of the spectrum, with very low impedance and high sensitivity IEMs, such as the Campfire Audio Holocene (5 ohm impedance), background hiss is magnified if you push the volume up without music playing.

The prime problem, however, is the reduction of overall dynamic range, as the noise floor eats into the “quietest passages” of the music. For me, it was mostly a non-issue, as even the Holocene are well within the realm of “tolerable” in terms of background hiss.



If you are particularly sensitive to background hiss, something like the iFi IEMatch will come in handy, though it requires an additional purchase.

Lastly, I paired the S9 Pro Plus with high impedance loads (>150ohm) and planar magnetic headphones/IEMs. Planar magnetic drivers usually prefer high current, while high impedance dynamic drivers require high voltage swing.

There are better choices than the S9 Pro Plus for headphones like the Sennheiser HD 800S. The bass sounds noticeably less full, and lower mids are thinned out as a result. The Sennheiser HD 660S2 show similarly toned-down bass but do not suffer the midrange hollowness as much due to their elevated low end.

As for the planar devices, the Campfire Supermoon are driven well with adequate dynamics, while the Hifiman HE400se are not as punchy in the bass as on higher-powered desktop sources. The notorious Hifiman HE6se V2 (82 dB/mW @50ohm) are even less favorable in this regard, sounding lifeless and barely getting loud with the S9 Pro Plus maxed out.

So overall, if I have to summarize the amplification prowess of the S9 Pro Plus, it will be as follows:

• Low impedance (16-150ohms) and high sensitivity (>95dB/mW) loads are well driven.
• Very low impedance (<15ohms) and low sensitivity (<95dB/mW) loads are not ideally driven.
• High impedance and high sensitivity loads are moderately well driven.
• High impedance and very low sensitivity loads are a no-go.

Comparisons​

Vs Moondrop Dawn 4.4​

The Moondrop Dawn 4.4 is priced similarly but has some distinct differences.

Firstly, the Dawn 4.4 has a fixed type-C cable. Secondly, there are no hardware buttons to control volume, etc. Finally, there is only one output (4.4mm balanced), so you’ll need a balanced cable for any headphones or IEMs you wish to power.

For all these omissions, what you get in return is class-leading output power and app support. The noise floor is also lower than the S9 Pro Plus.

Depending on the end-user’s needs, either of these dongles in the USD$50-$100 price range are great options. If you need absolute performance, the Dawn 4.4 is the ideal choice. The Hidizs S9 Pro Plus is the better option for those requiring more flexibility.

Final Thoughts​

The Hidizs S9 Pro Plus is an overall upgrade over the last model. That much is certain.

What’s not so immediately evident is the competition from the likes of Moondrop. The Dawn 4.4 measures just as well, while offering better output power and app support. The S9 Pro Plus has more usability perks, but the slightly weaker amp section holds it back.

That being said, the S9 Pro Plus is solid all around. Barring the wobbly volume buttons, everything worked as expected during my review period. It’s not too expensive, is well-built, and sounds good without being boring or sterile.

I wish the S9 Pro Plus stood above the rest in more aspects, but sometimes, simplicity is all you need, and this particular dongle nails that role.