Fosi Audio SK02 : Neutral and Powerful

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+Neutral sound signature

+Crystal clear sound output

+Multifunctional volume knob

+Powerful power output

+3.5mm SE and 4.4mm Balanced terminations

+Built like a tank

+Plug and play dac/amp

+Great technicalities


-Features like software app for volume control (subjective)

-Kind of bulky





SK02 is a DAC/AMP offers portability and high power output driving music gear with ease. It a simple plug and play source which uses 3.5mm and 4.4mm Balanced terminations. The multifunctional volume knob is huge plus for a portable DAC/AMP you can adjust the volume to your liking in a most convenient way.




I would like to thank Fosi Audio for arranging a unit for me. My opinions are unbiased, and I haven't been influenced or instructed to praise these gear. Every detail in this review is actual experience made by listening for hours everyday.






Model : SK02

Input :  USB/OPT

Output : 3.5mm Headphone,4.4mm Headphone,3.5MM line out/OPT

Amp output maximum power


3.5MM :


High Gain: 280mW@32Ω, 130mW@64Ω, 40mW@250Ω, 30mW@300Ω


Low Gain: 90mW@32Ω, 50mW@64Ω, 15mW@250Ω, 10mW@300Ω


4.4MM :


High Gain: 1100mW@32Ω, 550mW@64Ω, 150mW@250Ω, 120mW@300Ω


Low Gain: 350mW@32Ω, 180mW@64Ω, 50mW@250Ω, 40mW@300Ω


Frequency Range 20Hz-20kHz (±0.02dB)


THD ≤0.001% @ 1kHz


SNR  :

3.5mm Headphone :

Low Gain:116dB


High Gain:120dB



4.4mm Headphone :


Low Gain : 110dB


High Gain : 115dB


Headphone matching impedance 16-300Ω


PC-USB Sampling Rate 32Bit/384KHz DSD256


OPT Sampling Rate 24Bit/192KHz


DAC Chip ES9038Q2M


Device Dimension 4.76*2*1.69inch (121*51*43mm)


Net Weight 0.84lb/380g


Power Supply 5V, USB Type-C






Fosi Audio Sk02 Headphone Amp

2-in-1 USB-A/C to C Cable

User’s Manual



Build and features


The build is made from aluminum CNC ensures solid durability and long lasting use.


The Multifunctional volume knob serves as volume adjustments, play/off button and to turn on/turn off the SK02.


It also features low/gain mode buttons for quick switching to your liking


The light indicator helps the user to determine the sampling rate of songs.


The high power output of SK02 whooping 1100mw driving mostly of your gears with ease.



Sound Aspects


Fosi Audio SK02 sounds neutral and analytical. Bass is clean and well- controlled it has enough punch and texture. I just want to emphasize the highs have more bite lowering the volume help this department. Technicalities is above average for the asking price. It picking up enough micro details and nuances as well as creating wide stage performance.



Source used :


Rosetechnics Quietsea

Tangzu Xuan NV

EPZ Q1 Pro

Letshuoer DZ4



Stock Cable


This DAC spend 30-40 hours of burn in before taking details of this review







With Rosetechnics Quietsea

The bass shows tactility and more punch. The V shape tuning of quietsea affects the mids become recessed but with sk02 it helps the mids to make more frontal presentation. As for the highs it has more bite and crisper quality


With Tangzu Xuan NV

It is a neutral-warm tuning benefits more with this SK02. It shows more controlled and textured bass. Mid is smooth and lusher. Vocals is airier and more intimate. Treble is still safe and engaging enough to enjoy the presentation.




With EPZ Q1 Pro

Another harmanish tuned gear synergized well with SK02. It has already full sounding bass but when paired the bass takes it to another whole new level. It is tighter, punchier and well controlled. Mids is airer and more frontal. Treble is livelier and engaging. The technicalities have noticeable improvement such as imaging snd layering.




Letshuoer DZ4

A neutral gear which focuses vocal clarity. It has clean and coherent sounding bass which not appealing to everyone. The mids is the star of the show here the techs of SK02 helps this department. The vocals is lusher, airer and more intimate presentation. Also it helps the treble of DZ4 a little livelier.






The SK02 is a versatile DAC/AMP that you can carry on the go or some desktop setup. This is the most powerful DAC/AMP I've used in this price range whooping 1100mw which is crazy imo whatever your gears is. I'm easily recommend this SK02 for those people who looking for a budget decent desktop setup.

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