Fosi Audio has entered the audio streaming market with the release of the S3, a compact device offering high-resolution audio support and extensive connectivity.
Priced at 279.99 euros, the streamer is designed to modernise traditional Hi-Fi setups by adding compatibility with services like Spotify Connect, Apple AirPlay 2 and Google Cast.
The manufacturer, known for demonstrating that affordable equipment does not mean low quality, positions the S3 as a direct competitor to entry-level devices like the WiiM Pro. Fosi Audio has previously drawn positive reviews for its dedicated phono preamps and full Hi-Fi stacks.
Compact design and physical controls
The unit measures 17.3 by 17.3 centimetres with a height of 4.7 centimetres. It features a dark grey aluminium chassis with clean lines, dominated by a large orange volume control dial on the front panel.
The device lacks a front display. Users interact through two small physical buttons: one for power and input selection, and another for Bluetooth pairing and output selection. Status indicators rely on colour-coded LEDs, which can be difficult to interpret in low light without memorising the corresponding functions.
Instead of physical displays, control of the device relies heavily on the redesigned Fosi Audio companion application, available on Google Play and the App Store. The Bluetooth remote control provided with the S3, which has a range of more than 15 metres, is functional but primarily suited for immediate operations such as powering the unit on or off and pausing playback when a phone call arrives. Approximately 90 percent of operations are handled through the application, which responds instantly with virtually no latency.
Connectivity and internal hardware
Despite its compact size, the S3 features a densely populated rear panel. The layout groups analogue outputs at one end, digital audio connections in the centre, and network and power connections at the other.
The connectivity options include XLR balanced and RCA outputs, an RCA input, optical input and output, a 10/100M Ethernet port, HDMI eARC, an active subwoofer output, and a 12-volt trigger. The device is powered by a 12-volt, 1.5-ampere DC supply.
Internally, the S3 is powered by an Amlogic A113X chipset. Digital-to-analogue conversion is handled by an AKM AK4493SEQ chip, paired with a Texas Instruments OPA1612 operational amplifier.
The streamer supports dual-band Wi-Fi across 2.4 GHz and 5 GHz frequencies, alongside Bluetooth 5.3 with A2DP, AVRCP and BTLE profiles. It is compatible with SBC and AAC codecs. Supported streaming protocols include DLNA, Roon Ready, Tidal Connect and Qobuz Connect.
Sampling rates vary depending on the connection. Optical and HDMI connections support 24-bit PCM audio at 192 kilohertz. Bluetooth handles 24-bit audio at 48 kilohertz, while Google Cast reaches 24-bit at 96 kilohertz. AirPlay 2 is limited to 16-bit at 48 kilohertz. For higher resolutions, Roon Ready and Wi-Fi connections support 32-bit audio at 384 kilohertz, and a local area network connection reaches up to 32-bit at 768 kilohertz.
Sound quality and performance
In practical testing with a Kenwood KR-V5080 receiver integrated into a conventional Hi-Fi system, the S3 produces a wide soundstage and good instrument separation. The mid-range frequencies provide warmth without nasal characteristics, while the high frequencies offer rapid transients and sufficient brightness, although they can occasionally feel slightly washed out on some recordings.
Testing with Jean-Michel Jarre's track "Chronologie IV" demonstrated the device's ability to render spatial effects effectively, though it lacks some of the depth, separation and air between audio planes found in significantly more expensive equipment like the Eversolo DMP-A10.
The factory sound profile lacks some body and definition in the lower frequencies. The companion application includes an equaliser that allows users to adjust the bass response, though the device does not feature a dedicated room correction system to compensate for acoustic interactions in the listening space.
The S3 operates with a moderate temperature increase during use. The device dissipates heat through its chassis and bottom ventilation grille, meaning it should not be placed directly underneath or on top of other components.
Market alternatives
The S3 faces competition from the WiiM Pro, which retails for 179 euros. The WiiM Pro includes a more mature software ecosystem and RoomFit room correction software, but uses a more modest Texas Instruments PCM5121 DAC. It also lacks HDMI ARC, a dedicated subwoofer output and balanced XLR connections.
The WiiM Ultra, priced at 399 euros, offers a more comprehensive alternative. It features a larger footprint, a 3.5-inch touchscreen, an ESS ES9038Q2M DAC, a phono input, USB storage playback, a headphone connection and RoomFit. However, the Ultra does not support AirPlay 2 and lacks balanced XLR outputs.
Fosi Audio sells the S3 directly through its official website and retail partners like Amazon.
