The Fosi SK01 comes in the typical fosi audio box inside one finds a USB-C cable for charging, yes even though this looks like it would be one of those power brick plug in amplifiers, it is in fact internal battery powered and while its small its definitely not a portable. It has an all-aluminum design with both dial and quickset buttons for EQ , and The SK01 buttons that control features such as loudness, tone, and gain. as well. It also has a 2500mA battery with 6 hours of playback time.
Here is a basic assessment of the sound as you can change it so drastically.
As is out of the box the SK01 present with a just north of neutral sound and more toward balanced, it has a nice semitransparent sound with some nice details and separation. It mirrors the source superbly. Using the different buttons one can get to totally neutral or a very rich dynamic sound. It ran my most demanding headphones with good loudness. To be fair I tested it with my SMSL m100 a neutral sounding simple DAC. I really wish Fosi would make something like this as an all-in-one unit no need for a separate DAC, honestly that would be great. There is clarity and power here, I wouldn’t recommend very sensitive all BA and hybrid IEM but most single dynamic and planar work well with the SK01. As far as headphones, some of my duller ones become very exciting with just the press of a button. The EQ is well implemented and the BASS, MIDS, AND TREBLE is precise in control.
Afterthought:
The Fosio audio SK01 is one of those rare hidden gems that offers good sound, lots of features and build quality for less than expected. It’s built like a tank and is highly customizable sound wise. Truely a cool device.
Specifications
| Specifications | Details |
|---|---|
| Model | SK01 |
| Input | 3.5MM line in |
| Output | 3.5mm Headphone, 6.35mm Headphone, 3.5MM line out |
| Amp output maximum power | High Gain: RMS 2400mw/ 32Ω,Low Gain: RMS 300mw/32Ω |
| Frequency Range | 20Hz-20kHz (±0.5dB) |
| THD+N | 0.001% @ 1kHz and 770mV |
| SNR | ≥108dB |
| Headphone matching impedance | 16-300Ω |
| Device Dimension | 4.76*2*1.69inch (121*51*43mm) |
| Net Weight | 0.641b/290g |
| Power Supply | 5V, USB Type-C |
Headphones and Coffee 