FiiO S15 Desktop Hi-Res Audio Streamer

The FiiO S15 is FiiO’s first full-size, all-in-one media streamer, made to be the centre of a living-room hi-fi system: a media and network streamer, LAN and local player, DAC, preamplifier and digital source in one 430mm-wide, all-metal case. AKM’s flagship AK4191 + AK4499EX feed a fully balanced analogue stage and a 35W linear power supply, a 7.84-inch automotive-grade touch screen runs Android 12 with FiiO’s landscape interface, and HDMI, HDMI ARC, AES and I²S connect it to a TV or high-end DAC as easily as to an amplifier. It won EISA’s Best Product award for streamers in 2025–2026, as well as a VGP 2025 Summer Life Style award and a MicroComputer Editors’ Choice 2024. There is no headphone output: it feeds an amplifier, active speakers or a headphone amp.

Full size and rock solid

At a standard 430mm wide, the S15 sits neatly alongside your other separates for a unified system, and its heavy all-metal body (about 5.6kg) and stable non-slip feet guard against sound degradation from vibration.

Everything covered

Install and use streaming apps on Android 12; stream with Roon Ready, AirPlay, DLNA or Bluetooth; play music from a NAS, your network or cloud servers over UPnP, SMB and WebDAV; and play local files from internal storage, microSD cards, USB flash drives, portable hard drives or an M.2 SSD. Eleven working modes cover it all: Android, Pure Music, Roon Ready, AirPlay, Bluetooth receiver, USB DAC, coaxial, optical, AES, HDMI IN and HDMI ARC. A Snapdragon 660, 4GB of RAM and 64GB of storage (about 46GB available) keep it responsive.

AKM’s flagship DAC combination

Like FiiO’s Q15, K9 AKM and M23, the S15 uses AKM’s acclaimed AK4191 + AK4499EX. The design fully separates the digital and analogue sections and adds AKM’s “DWA ROUTING” technology, raising the signal-to-noise ratio and reducing noise at every level, for a cleaner background, better resolution and a natural, relaxed, unstrained sound.

Fully balanced, with a 35W linear supply

Everything from the DAC to the preamp stage is fully balanced, greatly reducing noise and crosstalk and improving the line and preamp outputs, which you can set to a fixed level or a variable preamp level. OPA1612 low-noise precision op-amps, on a high-voltage supply, handle the I/V, low-pass filter and other stages so the dynamics of your music come through faithfully. The XLR output delivers 4.8Vrms as a line out or up to 8.9Vrms as a preamp, with a signal-to-noise ratio of up to 131dB, and six low-pass filters let you fine-tune the sound.

A custom high-quality, low-noise transformer powers a 35W linear supply, with four 4,700µF ELNA audio capacitors as a generous reserve. The digital and analogue circuits have separate supplies, the analogue section has a multi-stage supply with many precision LDOs for the DAC and filter stages, and the digital, analogue and power sections are physically separated and shielded so they don’t interfere.

Precise clocks and no resampling

For the first time FiiO uses two fully screened ACCUSILICON AS318-B ultra-low phase noise femtosecond oscillators (45.1584MHz and 49.152MHz), which reduce the effect of phase noise for highly accurate decoding and digital output, so the S15 can also be a reference-grade source for high-end external DACs. FiiO’s DAPS digital audio purification system, its custom Android audio core with a low-jitter clock co-processor, avoids resampling throughout the apps and system and matches every PCM and DSD sample rate.

Quality parts

Twenty-four high-precision film resistors, eight WIMA film capacitors and four solid capacitors restore the energy and detail in your music, and ELNA electrolytic audio capacitors add to the soundstage. The coaxial and AES outputs each use a digital audio isolation transformer, which strengthens the output and prevents ground-loop interference, with isolation comparable to an optical connection. The RCA connectors are gold-plated copper, the internal wiring oxygen-free copper, and the XLR sockets are NEUTRIK.

Connections for the whole system

Digital inputs: a front USB-C port for use as a USB DAC through a 16-core XMOS XU316 (up to 768kHz/32-bit and DSD512), coaxial and AES (up to 192kHz/24-bit), optical (96kHz/24-bit), HDMI IN (192kHz/24-bit) and HDMI ARC. Outputs: XLR and RCA line or preamp outputs; coaxial and AES (up to 384kHz/24-bit and DSD128) and optical (192kHz/24-bit), which can also pass a digital input straight through; I²S over HDMI for DACs with an I²S input, with four pin layouts for different brands; HDMI out; USB audio to an external DAC; and Bluetooth transmission to wireless headphones with LDAC, LHDC, aptX HD, aptX, AAC or SBC. Two USB-A ports take flash drives and hard drives, and the rear USB-C port handles storage and file copying from a computer. A 12V trigger output (with a 3.5mm cable included) switches other equipment on and off with the S15, and a ground switch and M6 grounding terminal help with ground loops. Ethernet (100Mbps) and dual-band Wi-Fi connect it to your network.

Store a large library

A high-speed USB 3.2 M.2 SSD cage is included for storing and managing a large library (the SSD is not included). It takes M.2 SATA or NVMe (PCIe 3.0) drives in 2230, 2242, 2260 and 2280 sizes, up to 2TB, formatted as NTFS or exFAT.

HDMI and HDMI ARC

With HDMI 2.0 decoding, HDMI output and HDMI ARC, the S15 becomes the audio heart of your home cinema: decode sound from a Blu-ray player, set-top box or computer at up to 192kHz/24-bit, or take the audio return channel from your TV at 44.1 or 48kHz, all controlled from the included remote.

A big screen and many ways to control it

The 7.84-inch automotive-grade colour touch screen (1,280 × 400) is larger than similar products have, and FiiO’s new landscape interface, with a landscape version of FiiO Music and VU meters, is clear and intuitive. Rearrange the home screen as you like. The left knob switches the S15 on, chooses modes and navigates, and the right knob controls volume and play/pause, while two virtual keys handle back and track control. The included RM3 Bluetooth remote (AAA batteries) controls playback and volume, adds tracks to your favourites with one click and supports gestures, and the companion app’s dual-screen feature puts full control of the S15 on your phone. The knob lights show the Bluetooth codec or the sample rate.

Fine-tune the sound with the 10-band PEQ (frequency, gain, bandwidth and Q, plus eight presets), All to DSD and channel balance in 0.5dB steps.

Good to know

• Before first use, check that the voltage switch underneath is set to 230V for the UK, then turn on the AC power switch on the back (it is off by default).
• The coaxial, optical and AES outputs are off by default; turn them on in the audio settings. Turning on I²S output mutes the analogue outputs, and using USB audio or Bluetooth output turns off the other outputs.
• There is no headphone output; for a matching headphone amp, see FiiO’s K19.
• In the box: S15, RM3 Bluetooth remote, AC power cord, spare fuse, M.2 SSD cage with data cable, screwdriver and instructions, 3.5mm trigger cable, USB dust plugs and quick start guide.