FiiO M15S

The FiiO M15S is a high-end audiophile player. This portable player incorporates quality components in a compact format, offering great versatility thanks to its multiple operating modes. Designed for demanding audiophiles, it combines power, precision, and modern connectivity in a carefully engineered package.

Technical Architecture and Sound Performance

At the heart of the M15S is the ES9038PRO digital-to-analog converter, a reference component used in professional studio equipment. This chip utilizes a parallel architecture with 8 independent channels, enabling a fully differential output that minimizes distortion and enhances stereo separation.

Amplification relies on a dual configuration of OPA926 operational amplifiers, renowned for their linearity and low background noise. This combination delivers remarkable output power, capable of efficiently driving both sensitive earphones and demanding planar headphones.

The analog section receives special attention, with the use of film resistors and Panasonic capacitors selected for their acoustic properties. Multi-layer shielding protects sensitive circuits from electromagnetic interference, while dual NDK crystal oscillators ensure precise digital signal synchronization.

Versatile Operating Modes

The M15S stands out for its ability to operate in several modes tailored to different uses. Android mode provides full access to streaming apps while preserving audio quality through global bit-perfect playback. This approach allows you to use services like Qobuz or Tidal without compromising sound fidelity.

Pure Music mode prioritizes audiophile performance by disabling non-essential Android system functions. This configuration optimizes resources for audio playback and reduces potential sources of digital interference.

The USB converter function transforms the M15S into an external DAC for computers, leveraging its conversion capabilities to enhance a computer audio system. The Bluetooth receiver mode allows for high-quality wireless signal reception, while AirPlay compatibility makes integration into an Apple ecosystem easy.

Connectivity and Audio Formats

The M15S’s connectivity covers all modern needs with Bluetooth 5.0 and the QCC5124 chip, supporting advanced codecs like LDAC, LHDC, and aptX Adaptive. Dual-band Wi-Fi enables access to streaming services and DLNA compatibility for playback from a network server.

Audio outputs include all three standard connectors: 3.5 mm single-ended, 2.5 mm balanced, and 4.4 mm balanced, as well as a line out and coaxial output. This variety ensures compatibility with all types of headphones and audio systems.

Audio format support ranges from classic MP3 to DSD256 files, including high-resolution formats up to 384 kHz/32-bit. Full MQA decoding lets you enjoy recordings in this technology, while the “All to DSD” function converts all formats to DSD for a distinctive sound coloration.

Thermal Management and Power Supply

The M15S’s thermal design incorporates advanced materials like graphene to efficiently dissipate heat generated by power components. This approach maintains stable performance even during intensive use with hard-to-drive headphones.

The dual power supply system is a notable innovation: it automatically switches between the internal battery and USB power as needed. Desktop mode completely bypasses the battery during stationary use, thus preserving its lifespan.

Battery life varies depending on usage mode and connected load, with about 10.5 hours on single-ended output and 9 hours on balanced output. QC3.0 fast charging allows a full recharge in approximately 3.5 hours.

Design and Ergonomics

The M15S features a sleek, professional design, prioritizing functionality over flashy aesthetics. The metal construction provides effective protection for internal components while aiding in heat dissipation.

The user interface combines a precision rotary encoder with 120 volume levels and digital buttons for fine, intuitive control. The touchscreen enables smooth navigation through menus and music libraries.

The single microSD slot, expandable up to 2 TB, may seem limiting compared to some competitors offering two slots, but remains sufficient for most uses thanks to current memory card capacities.

Specific Use Cases

The M15S is primarily aimed at mobile audiophiles who want to maintain high listening quality on the go. Its output power makes it a relevant choice for owners of planar or high-impedance headphones that are traditionally difficult to drive.

For stationary use, its USB converter function can significantly improve the audio quality of a laptop or desktop computer. Roon Ready compatibility makes it easy to integrate into a connected home audio system.

Musicians and sound engineers can use it as a portable reference for critical listening, thanks to its tonal neutrality and ability to reveal recording details.

Technical Specifications

Converter and Amplification

• Digital-to-analog converter: Desktop-grade ES9038PRO with 8 independent D/A channels in parallel architecture for fully differential output
• Amplification section: Dual OPA926 operational amplifiers for clean, controlled, and powerful output
• Output power: Up to 1,200 mW per channel
• Multi-stage audio circuit: Film resistors and Panasonic capacitors for minimal distortion
• Gain: 5 levels including an “enhanced over-ear” mode (USB power only)
• Dual volume control: Precision rotary encoder with 120 levels + digital buttons

Operating Modes

• Android: Full use of apps with global bit-perfect playback
• Pure Music: Dedicated audiophile mode
• USB Converter: External converter function
• Bluetooth Receiver: Wireless audio reception
• AirPlay: Streaming from Apple devices
• Roon Ready: Full integration with Roon

Connectivity and Storage

• Bluetooth 5.0 with QCC5124: SBC, AAC, aptX family, LDAC, LHDC, aptX Adaptive
• Wi-Fi: Dual-band 2.4 GHz / 5 GHz with DLNA, AirPlay, Roon Ready
• Storage: Single microSD slot, expandable up to 2 TB
• Connectors: 3.5 mm single-ended, 2.5 mm balanced, 4.4 mm balanced, line out, coaxial (shared)
• USB: Type-C USB 3.0 for charging / data / converter function

Supported Audio Formats

• Lossless: DSD (up to DSD256), FLAC, APE, ALAC, AIFF, WAV up to 384 kHz / 32-bit
• Lossy: MP3, WMA, AAC, OGG
• MQA: Full decoder up to 8x
• DXD: Up to 352.8 kHz / 24-bit
• DTS (2 channels): Up to 192 kHz / 24-bit
• All to DSD: Direct conversion of all sources to DSD format

Audio Performance

Single-ended Output – Ultra High Gain

• Output power (32 Ω): ≥ 580 mW + 580 mW
• THD+N: ≤ 0.0005%
• Signal-to-noise ratio: ≥ 122.5 dB
• Noise floor: ≤ 3.2 μV
• Frequency response: 20 Hz – 50 kHz (-1.0 dB)
• Output impedance: ≤ 1.4 Ω

Balanced Output – Ultra High Gain

• Output power (32 Ω): ≥ 1,200 mW + 1,200 mW
• THD+N: ≤ 0.00075%
• Signal-to-noise ratio: ≥ 121.5 dB
• Noise floor: ≤ 5.2 μV
• Frequency response: 20 Hz – 50 kHz (-1.0 dB)
• Output impedance: ≤ 2.3 Ω

Line Out

• THD+N: ≤ 0.00034%
• Signal-to-noise ratio: ≥ 124 dB
• Output level: 2.0 Vrms (single-ended) / 4.0 Vrms (balanced)

Battery Life and Power Supply

• Single-ended mode (3.5 mm): approx. 10.5 h
• Balanced mode (4.4 mm): approx. 9 h
• Deep standby: over 1,000 h
• Charging time: approx. 3.5 h with QC3.0 fast charging
• Dual power supply: Seamless switching between battery and USB fast charging with automatic voltage optimization
• Desktop mode: Bypasses battery charging/discharging to prevent wear

Design and Cooling

• Multi-layer shielding: Protection of analog and digital sections to minimize interference
• Advanced heat dissipation: Advanced thermal design with graphene and metal shielding to ensure stable high output
• Dual NDK crystal oscillators: Phase-locked loop for low-jitter audio processing
• 4th generation FPGA: Audio purification system (DAPS) designed by FiiO
• Smart thermal and battery protection: Automatic temperature regulation

General Specifications

• Weight: approx. 345 g
• Dimensions: 140 × 80 × 18.9 mm
• Display: 5.5-inch Full-Fit (1440 × 720)
• Internal storage: 64 GB / approx. 46 GB usable
• RAM: 4 GB
• Processor: Qualcomm Snapdragon 660 + Android 10
• Equalizer: 10 bands with presets and full customization
• Firmware update: Local and OTA (over-the-air)

Package Contents

• FiiO M15S
• Leather case
• DK3S heat dissipation dock
• USB-C cable (data/charging)
• USB power cable for dock
• USB adapter
• Quick start guide
• Warranty card
• microSD ejector
• GPL license manual