The Fosi SK02 presents itself as a compact desktop DAC/AMP with a vertical design, ideal for space-conscious users. But don’t let its desktop aesthetic fool you – the SK02 offers remarkable versatility, making it suitable for mobile use as well.
The metal housing is both durable and elegant, and it fits seamlessly into any desktop setup or on-the-go powerful audio rig. It is available for $99.
Disclaimer:
This review unit of the Fosi SK02 was generously provided directly by Fosi Audio. While I appreciate their support, all opinions expressed in this review are my own and based on my independent testing and experience. I strive to remain objective and transparent in my evaluations, offering an honest and unbiased perspective for potential buyers.
Unboxing
The Fosi SK02 arrived in a sleek and minimalist box with the phrase ‘HiFi Made Fun’ written on it, which set the tone for what was inside.
Upon opening the Fosi SK02 box, the sleek metal device was revealed, concealed in protective foam. Additionally, I found a user manual and a USB Type-C to Type-C cable with a USB Type-A to Type-C adapter, making it suitable for various devices.
Design and Build Quality
The SK02’s vertical design stands out from the crowd, occupying minimal desk space and making it easy to carry with you when you are on the go. Although you may not be able to put it in your pocket, it is still small enough to easily fit in your bag and be a very strong portable companion. Although it has a distinct visual appearance, it may not appeal to everyone’s aesthetic preferences.
The large volume knob doubles as a power button and play/pause control, offering convenient operation. However, its lightweight feel and susceptibility to accidental adjustments detract from the user experience. Additionally, the volume level light indicator is very inconvenient to use, as it shows the volume level by its changing flashing brightness, and the absence of an LCD display makes checking volume levels slightly harder.
Technical Specifications
- DAC Chip: ESS Sabre ES9038Q2M
- Operational Amplifier: SGM8262
- Maximum Sample Rate: PCM 384kHz/32bit, DSD256
- Input: USB Type-C, SPDIF (shared)
- Output: 3.5mm single-ended, 4.4mm balanced (high gain 32Ω: 280mW/3.5mm, 1100mW/4.4mm / low gain 32Ω: 90mW/3.5mm, 350mW/4.4mm)
- SNR: 3.5mm – Low Gain 116dB / High Gain 120dB. 4.4mm – Low Gain 110dB / High Gain 115dB
- Distortion: ≤0.001% @1kHz
- Noise Floor: 3.5mm – 3.7μV / 4.4mm – 12μV
- Crosstalk: 3.5mm – Low Gain 128dB / High Gain 137dB. 4.4mm – Low Gain 112dB / High Gain 110dB
- Frequency response: 20Hz-20kHz (±0.02dB)
- Headphone impedance: 16-300Ω
- Input voltage: DC 5V
- Hardware Controls: Power, volume, high/low gain switching, input switching
- Dimensions: 130mm (H) x 62mm (W) x 23mm (D)
- Weight: 340g
Versatility and Connectivity
The Fosi SK02 stands out for its remarkable versatility and connectivity options, catering to a wide range of audio setups and preferences. The ability to work as a standalone device that is powered solely by a mobile phone is a key feature, making it portable and convenient for on-the-go setup.
Moreover, the SK02 offers multiple connectivity options to accommodate various audio sources and devices. It features a standard 3.5mm headphone jack, which can be used to connect to a wide range of headphones and in-ear monitors (IEMs), a 4.4mm balanced output, which packs the real punch, and an additional rear 3.5 AUX output.
In terms of input options, the SK02 offers flexibility with its optical input, allowing users to connect digital audio sources such as computers, gaming consoles, or TVs for high-fidelity sound reproduction. This optical input expands the versatility of the SK02, enabling seamless integration into almost any audio setup.
Additionaly Fosi SK02 offers SPDIF output from the rear 3.5mm optical output, effectively functioning as a 2-in-1 feature alongside the rear 3.5mm AUX output. This dual functionality enhances the connectivity options of the SK02, allowing users to utilize either the optical output for digital audio as an “adapter” or the AUX output.
Overall, the Fosi SK02 impresses with its versatility and connectivity options, making it a versatile audio companion for audiophiles, music enthusiasts, and casual listeners alike. Whether used as a portable headphone amplifier or as part of a home audio setup, the SK02 delivers high-quality sound performance and flexible connectivity.
Controls and User Experience
The SK02 prioritizes user convenience with intuitive controls and clear indicators. The volume knob, despite its lightweight feel, offers precise volume adjustments with numerous levels of volume for more personalized adjustments. Additionally, a single button seamlessly toggles between the low and high gain modes, denoted by LED lights, empowering users to optimize performance based on their headphone/IEM requirements and listening preferences.
Further enhancing versatility, the SK02 conveniently allows you to switch between optical and USB input sources at the press of a dedicated button. This flexibility caters to various connection preferences and seamlessly integrates the SK02 into different setups, be it your computer, mobile phone, or a dedicated media source with optical output or even an optical input.
Additionally, there is a sampling rate indicator, which goes from 44.1kHz to 384kHz, and a DSD indicator from 64 to 256. However, the flashing and brightness-changing volume indicator, while attempting to convey loudness levels, may prove distracting and less informative in practice.
Power
The Fosi SK02’s multiple output options give it the possibilities for various audio setups. It features a 3.5mm single-ended output on the front panel, which delivers 280mW (on high gain) clean and detailed sound suitable for a wide range of headphones and earphones. This output provides ample power to drive most IEMs and headphones efficiently, ensuring a satisfying listening experience without compromising on audio quality.
In addition to the 3.5mm single-ended output, the SK02 also boasts a 4.4mm balanced output on the front panel, which brings 1100mW (on high gain). The balanced output offers several advantages, including improved channel separation, reduced crosstalk, and lower distortion compared to single-ended connections. It delivers a more powerful dynamic sound, which can drive more power-hungry headphones and even planar headphones.
Furthermore, the SK02 features a rear 3.5mm AUX output, providing users with added flexibility in their audio setups. While this rear output delivers less power compared to the front 3.5mm output, it still offers sufficient amplification to drive a wide range of IEMs with ease. Whether connecting to speakers, amplifiers, or other audio devices, the rear 3.5mm output ensures reliable and versatile connectivity.
Sound Performance
The Fosi SK02 delivers a sound signature characterized by a more bright, detailed presentation. showing itself as a revealing performer. At its core lies the ESS Sabre ES9038Q2M DAC chip, known for its clean and crisp delivery. This translates into the SK02’s most defining characteristic: a pronounced mid-treble emphasis.
This emphasis results in shimmering cymbals, airy vocals, and the intricate details of string instruments taking center stage. The SK02 excels at unearthing micro-textures and nuances, inviting listeners to delve deep into the sonic tapestry of their music. But be warned, this focus can become a double-edged sword. Harsh recordings or tracks heavy on high-frequency content might sound overly bright or even piercing to sensitive ears.
Vocals occupy a prominent space, delivered with clarity and precision. Every word and inflection carries weight, offering a transparent window into the artist’s expression. However, this analytical presentation might come at the cost of the warmth and fullness associated with the traditional “musical” midrange. Instruments like guitars and brass instruments may lack the organic body and richness found in warmer amps.
Bass presence remains solid, controlled, and tight, providing a foundation for the rest of the spectrum. It delivers enough punch to satisfy most genres but doesn’t overpower the mids and highs. However, bass-heavy listeners or those seeking a more impactful low-end rumble might find it wanting compared to warmer-sounding competitors like the Truthear Shio.
Overall, the Fosi SK02 caters to analytical listeners who prioritize detail and clarity. It shines with acoustic and classical music, where its ability to unveil intricate details is a strength. However, its bright emphasis might not be for everyone, especially those who prefer a warmer, more forgiving sound or listen primarily to bass-heavy genres.
Conclusion
In conclusion, the Fosi SK02 stands out as a versatile DAC/AMP that transcends its desktop-oriented design to offer mobile users a compact and powerful audio solution with the possibility to run only on a single USB. With its bright and detailed sound signature, sturdy build quality, and diverse connectivity options, the SK02 caters to audiophiles seeking a balance between portability and performance. While minor ergonomic concerns exist, they do little to diminish the overall appeal of the SK02 as a versatile and capable audio-on-the-go companion for both desktop and mobile use. This all-inclusive package is priced at $99, making it a great all-arounder for those who want it to do everything on a limited budget.
Pros:
- Good build quality and visually distinct vertical design.
- Clear, detailed, and analytical sound signature.
- Versatile connectivity options with USB-C, SPDIF IN/OUT, and rear AUX out.
- Powerful output, especially through the balanced 4.4mm jack, suitable for demanding headphones.
- Large volume knob with multiple functions (power, play/pause).
- Easy to use with no complex setup.
- Sampling rate indicator lights.
Cons:
- Lightweight and easily adjustable volume knob, prone to accidental changes.
- Inconvenient volume-level light indicator.
- Brighter sound signature with emphasis on mids and highs, potentially fatiguing for some.
- Kind of brick bulky…
Where to buy:
Amazon US
Official site
Aliexpress
Promo code: FASKMKT15 (expired on 31st, March)