KingSound KS-H04 headphones and KingSound M-03 portable headphone amp

KingSound KS-H04 + M-03
KingSound KS-H04 + M-03


Director Castelli complains all the time that I never listen to him: and he is right! I mean, thanks to him It's almost two years that I don't leave home without headphones on! I can't even come up with an excuse to go without them, since now the headphones- amplifier, alas, is portable.

So, please avoid to call me on the phone, ring the intercom, let alone invoke my attention screaming from across the street! I'm busy, man. I must try the new KingSound KS-H04 headphones with the M-03 portable amplifier. I know, I might look a bit unsocial, but how can you light-heartedly stop the flow of emotion? At least with my headphones on, I have a good excuse: "Sorry, I didn't hear you, I'm listening to music!". So if you see me around wearing my headphones, please ignore me. Warn me only if a car is coming my way, or worse a truck or a bus: those are gonna hurt!


KingSound KS-H04 + M-03


Squaring the circle or the Columbus egg?

By now, I can say that I know well the KingSound's products dedicated to headphones' listening. I was lucky enough to try all their current production, thanks to the kindness and availability of the manufacturer and the Italian importer. You will be able to find on this web site two other articles concerning the models KS-H03 + M-20 and KS-H02 + M-10, I invite you to take a look at these reviews to get an overall idea of their products and learn about the history and character of this interesting company, which is based in Hong Kong. On the same articles, you will be able to read some first notes and general notions regarding headphones, electrostatic loudspeakers and amplifiers.

Let's now see, the main innovations introduced in the new product we are testing, compared with the old ones. For the first time, the KS-H04 ear cups abandon the circular design an elliptical one, taking up less space on our head. The connection cables are detachable, with two different lengths available: 1 m (included in the package) and 2.5 m (optional). The unit can easily be taken everywhere you go, making this new product portable. It also doesn’t forget the style, since the cute M-03 amplifier comes in different and catching colours, as you can see from the image below.

KingSound M-03

The case is very elegant and practical, it resembles the carrying bag of a small laptop and contains everything you need: headphones, an amplifier with its housing, and headphones' connection cables > AMP and source > AMP, the latter 50 cm long, at the end of it we find the 3.5 mm stereo jack.


From a technical point of view

This time I would like to start from the compact yet performing, amplifier M-03, 450 g of pocket-like solidity. An object that I would define excellent and extremely versatile. In addition to its primary function of running the headphones, this little guy is also equipped with a dynamic output type, capable of delivering 125 mW on 32 ohms of load. It does not end here: it can also take on the task of Power Bank, or emergency battery to support electricity for your smartphone or portable media player that you will use, presumably, as a signal source. The M-03 can be recharged through a common micro-USB battery charger - like the ones used for mobile phones - obviously, it is possible to charge it even from USB of your PC. In terms of battery life, I was really surprised: more than 22 hours of normal use before the battery's LED, emitting only one small flash, warned me that my remaining charge was 25%. If you also use it as a Power Bank it is reasonable to expect shorter times between one charging cycle and the next one. I liked the idea of the small blue flashing LED to indicate the remaining charge: 4 pulsations 100%, 3 for 75%, 2 for 50%, 1 for 25%.

KingSound did an amazing job in terms of comfort and weight balance with the KS-04. I rarely wear headphones for long periods and almost forget about having them on my head. The earpads are soft and comfortable, and the ear cups can rotate 180 ° outwards to reduce substantially the overall dimensions. The self-adjusting bow performs its work very well, even on my big head! The quality of materials and manufacture are excellent. The connecting cable is detachable allowing you to switch to a bigger length one, if needed.



I feel the need, yet again, to recommend an adequate and long trial period, before giving any judgments. All the headphones, electrostatics one more than others, need to be in use for sometimes, before reaching a certain timbre maturity. In the KS-H04, the low frequencies will initially seem attenuated and not very tangible, compared to the exuberance of the medium-high ones. After, approximately, fifty hours of use at medium volume, they will reach their balance, but do not be surprised if hundred hours in they start to sound even better. After this break-in phase, however, I must point out that, compared to KS-H03, there is less punch and presence on low and medium-low frequencies. At the same time, the impression is that the spatiality data is better than the other KingSound's models which showed greater airiness and the ability to place the instruments on the virtual stage. From a tonal point of view these headphones are definitely neutral, so the quality of the record is the one that makes a real impact on the sound outcome. I can't tell you what music genre to listen to, but if you like telluric and deep bass, choose another type of product. Even if the results, using smartphones and portable players as sources, have been more than good, the best sources for the little M-03 are the line outputs: a good preamp or a sound card. The driving capacities of the 3.5mm headphone output surprised me. No problem with the small, efficient headphones, both earphones - IEMs and over ear, but this, honestly, I did expect. On the other hand, the real surprise was the good comparison with difficult headsets like the HifiMan HE400. Nothing striking, but a level of reproduction more than decent and without perceiving distortions, which seems to me a good enough result. It came also in hand the possibility to use two outputs at the same time - more dynamic electrostatics - without problems for any of the two headphones.



The best words to describe this headset system are "small portable luxury". Honestly, I can't really picture anyone using the KS-H04 plus M-03 under the sun umbrella or while doing sports, for this activity are way more efficient small earphones and earbuds. It's another case if we want to enjoy our favourite music around the house, in the office (or those who can), or put them with their handy bag in the holiday suitcase.

I again want to praise KingSound on the quality, ergonomics, and beauty of its products. Maybe a cheaper street price could decree a good sales success with a refined audience that, as mentioned earlier, can afford, this small and beautiful luxury!



Selection of music we have listen to

Billy Talent - Afraid Of Heights (CD-2016)
Chelsea Wolfe - Abyss (CD-2015)
Daniele Silvestri - Acrobati (CD-2016)
David Bowie - Blackstar (CD-2016)
Deftones - Gore (CD-2016)
Igor Stravinsky - The Firebird and The Rite Of Spring - Royal Concertgebouw Orchestra (SACD-2008) SACD
Kaleo - AB (CD-2016)
Sóley - Ask The Deep (CD-2015)
Chris Cornell - Higher Truth (CD-2015)
Cincinnati Pops Orchestra - Orchestral Spectaculars, Erich Kunzel (Telarc CD-2002)
Erich Kunzel / Cincinnati Pops Orchestra Featuring King'singers ‎- Perform Music Of The Beatles (Telarc SACD-2001)
Leonard Cohen - Popular Problems (HD Tracks 24/96 - 2014)
Mozart - Requiem & Ave verum corpus - Riccardo Muti, BPO (Hybrid Stereo SACD)




Maximum rating ✳✳✳✳✳ Spark, ReMusic’s sparks

Timbre: ✳✳✳✳ | Very neutral, a little bit cold with recordings that have this characteristic.

Dynamics: ✳✳1 / 2 | The punch on the low frequencies is a bit lacking, the rest of the audio spectrum is well represented.

Detail: ✳✳✳ | Excellent level, particularly the micro detail.

Versatility: ✳✳✳1 / 2 | Great! Possibility to use two headphones separately or together an electrostatics and a dynamic, long battery life and a very convenient Power Bank function to be exploited. Detachable cables with the possibility to choose the most suitable length.

Image: ✳✳✳✳ | The best perceived so far with the KingSound’s headphones, really 3D virtual stage.

Aesthetics and functionality: ✳✳✳✳ | All very beautiful, elegant and without any drag in the use.

Performance price ratio: ✳✳✳1 / 2 | A small luxury that, if sold, perhaps in a bundle, at a lower price, could become a great sales success.

N.B. The Spark evaluation refers to the pair of KS-04 headphones with M-03 amplifiers.


Official technical specification


KingSound M-03 electrostatic headphone amplifier

Frequency response: 2Hz-24kHz, 90Vrms / output

Earnings: 60dB ESL, 22dB 3.5mm output

Total harmonic distortion + noise - THD + N: 0.028%

Maximum output voltage: 300Vrms ESL output - 3Vrms / 1Kohm 3.5mm output - 125mW / 32ohm 3.5mm output

Signal to noise ratio: 112dB

Input impedance: 20Kohm

Nominal input level: 300mV

Power supply output - Power bank: 6.200mAh plugged on USB

Weight: 0.45kg


KingSound KS-H04 electrostatic headphones

Frequency response: 6Hz-42kHz

Electrostatic capacity: 139pF

Impedance: 115Kohm at 10kHz

Sensitivity: 106dB to 100Vrms

Maximum sound pressure level: 116dB

Standard bias voltage: 550Vdc

Weight: 300g

Supplied connection cable: 1m, optional 2.5m


Official distributor Italy: to the Import Audio website

Official current price in Italy: KS-H04 headphones 1,220.00 EUR, M-03 549 headphone amplifier EUR, KS-H04 + M-03 bundle 1,769.00 EUR

Download here the KingSound Import Audio, official Italian distributor, price list

Associated equipment: to Mauro Cittadini’s system

by Mauro
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