The FiiO M15S is a high-end Android digital audio player designed to work both as a powerful portable source and as the centre of a desktop headphone system. Its ES9038PRO DAC, five gain levels and three wired headphone outputs make it suitable for everything from sensitive IEMs to demanding full-size headphones.

When connected to compatible QC/PD power, Desktop Mode bypasses the internal battery and unlocks Ultra High Gain. The included DK3S cooling dock supports longer desktop sessions, while Wi-Fi, two-way Bluetooth, AirPlay and Roon Ready provide flexible wireless playback.

Why it stands out

ES9038PRO desktop-class DAC architecture

The eight-channel ESS DAC is configured in a fully differential design, supported by dual OPA926 amplifiers and precision NDK oscillators for strong resolution, separation and dynamic range.

True battery-bypass Desktop Mode

With compatible external QC/PD power, the M15S can run without charging or discharging the battery and unlock Ultra High Gain for up to 1200mW + 1200mW at 32Ω from the balanced outputs.

Three headphone outputs and five gain levels

Use 3.5mm single-ended, 2.5mm balanced or 4.4mm balanced headphones, then select an appropriate gain level for sensitive earphones or harder-to-drive full-size models.

Six playback modes in one player

Switch between Android, Pure Music, USB DAC, Bluetooth Receive, AirPlay and Roon Ready modes for local files, streaming services, computer audio and wireless playback.

Best for

• Listeners who want one source for portable and desktop headphone listening
• Owners of both sensitive IEMs and demanding full-size headphones
• Users who still need a 2.5mm balanced output alongside 3.5mm and 4.4mm
• Roon, AirPlay and Android streaming users who also keep a large local music library

Not ideal for

• Buyers who want a small, lightweight pocket player
• Users who need cellular data, GPS or phone functions
• Anyone who requires the newest Android version for long-term app compatibility
• Extremely difficult headphones that require a dedicated high-power desktop amplifier

EMiUZEK Buying Notes

• The M15S runs Android 10. Check that any essential streaming app still supports this Android version before ordering.
• At approximately 345g, it is better treated as a transportable player than a lightweight pocket DAP. It can become warm during charging, high-gain playback or extended desktop use.
• Ultra High Gain and the maximum balanced output require compatible external QC/PD power. The included DK3S is a cooling stand; it does not replace the USB audio or power connection.
• The 3.5mm, 2.5mm and 4.4mm sockets share headphone/line-output functions, and 3.5mm also supports coaxial output. Confirm the selected output mode and lower the volume before connecting equipment.

Frequently asked questions

How does the M15S compare with the FiiO M23?

The M15S uses an ES9038PRO DAC, includes a 2.5mm balanced output and offers up to 1200mW + 1200mW at 32Ω in Ultra High Gain. The M23 uses an AK4191EQ plus AK4499EX architecture, is lighter in its aluminium version and has a separate USB-C power input for more convenient desktop use.

How does the M15S compare with the FiiO M17?

The M15S is smaller and easier to carry, while the M17 is the stronger choice for exceptionally demanding headphones and a more permanently desktop-focused setup.

Does Desktop Mode really bypass the battery?

Yes. With compatible external fast power, Desktop Mode supplies the audio circuitry directly so the battery is neither charged nor discharged during use.

Do I need a fast charger to use Ultra High Gain?

Yes. Ultra High Gain is available only when the M15S detects compatible external QC/PD power. On battery power, use one of the other four gain levels.

Is the DK3S an active USB dock?

No. The included DK3S is a heat-dissipation stand. Connect the M15S and external power or USB audio with the appropriate cables.

Is the M15S suitable for pocket use?

It is portable, but its 345g weight and 18.9mm thickness make it better suited to a bag, desk or careful handheld use than a light trouser-pocket setup.

Can I install streaming apps?

Yes. Compatible Android applications can be installed, but the player uses Android 10, so verify current support for any essential app.

Does it support Roon and AirPlay?

Yes. The M15S includes Roon Ready and AirPlay modes, in addition to Android streaming and Pure Music playback.

Does the M15S have cellular connectivity?

No. Online services require Wi-Fi or a suitable network connection; it has no SIM or mobile-data service.

Which headphone output should I use?

Use 3.5mm for single-ended cables, or 2.5mm/4.4mm for compatible balanced cables. Balanced output provides the highest available power, but cable termination and headphone requirements should determine the connection.

Can it drive sensitive IEMs?

Yes. Start with Low Gain and a low volume setting. The five-level gain system makes it easier to match both sensitive IEMs and full-size headphones.

Can it power every planar-magnetic headphone?

No portable player is ideal for every load. The M15S drives many demanding headphones well, but exceptionally inefficient models may perform better with a dedicated desktop amplifier.

Can I connect it to an amplifier or active speakers?

Yes. Set the selected 3.5mm, 2.5mm or 4.4mm socket to line-output mode and connect it to a compatible amplifier or active speaker input. Do not connect headphones while fixed line output is selected.

Does the 3.5mm socket support coaxial output?

Yes. The 3.5mm port can provide headphone, line or coaxial digital output depending on the selected setting and cable.

What is the maximum USB decoding rate?

As a USB DAC, the M15S supports up to PCM 384kHz/32-bit and DSD256. Its USB Audio digital output supports up to PCM 768kHz/32-bit and DSD512 with compatible downstream equipment.

What battery life should I expect?

FiiO rates playback at approximately 10.5 hours through the single-ended output and 9 hours through balanced output. Actual runtime varies with volume, gain, screen, wireless use and file format.

Can the internal battery be replaced by the user?

No. The 6200mAh battery is internal and is not designed for user replacement. Desktop battery-bypass mode can help reduce unnecessary battery cycling.

Can it transmit and receive Bluetooth audio?

Yes. It supports two-way Bluetooth 5.0. Available codecs depend on whether the M15S is transmitting or receiving and on the connected device.

How much storage can I add?

The player has 64GB internal storage, with about 46GB available to the user, and supports a microSD card up to 2TB.

HOW TO CONNECT

Local music or streaming to wired headphones

Source icon: Music player
Source: microSD / internal storage / Android streaming app
Connection: Local playback / Wi-Fi
Output connection: 3.5mm / 2.5mm / 4.4mm headphone output
Target icon: Headphones
Output: IEMs or full-size headphones

Note: Confirm Headphone Output mode, begin at low volume and choose gain according to headphone sensitivity.

Computer audio in USB DAC mode

Source icon: Computer
Source: Windows PC / Mac
Connection: USB-C data cable
Output connection: 3.5mm / 2.5mm / 4.4mm headphone output
Target icon: Headphones
Output: Desktop headphone system

Note: Windows may require the FiiO USB driver for full format support; select M15S as the computer's audio output.

Desktop listening with battery bypass

Source icon: Music player
Source: M15S local files / streaming / USB DAC
Connection: Compatible QC/PD external power
Output connection: 3.5mm / 2.5mm / 4.4mm headphone output
Target icon: Headphones
Output: High-power desktop headphone setup

Note: Place the player on the included DK3S, enable Desktop Mode and verify that external fast power has been detected before selecting Ultra High Gain.

Technical Specifications

Feature	Specification
Product type	High-resolution Android digital audio player
Operating system	Android 10
Processor	Qualcomm Snapdragon 660
DAC / amplifier	ES9038PRO / 2 × OPA926
Playback modes	Android, Pure Music, USB DAC, Bluetooth Receive, AirPlay, Roon Ready
Local and USB DAC decoding	Up to PCM 384kHz/32-bit; DSD256
USB Audio digital output	Up to PCM 768kHz/32-bit; DSD512
Headphone / line outputs	3.5mm single-ended; 2.5mm balanced; 4.4mm balanced
Digital output	3.5mm shared coaxial output
Maximum balanced power	1200mW + 1200mW at 32Ω; 368mW + 368mW at 300Ω in Ultra High Gain
Maximum 3.5mm power	580mW + 580mW at 32Ω in Ultra High Gain
Line-output level	2Vrms single-ended; 4Vrms balanced
Gain	Five levels; Ultra High Gain requires compatible external power
Display	5.5-inch, 1440 × 720
Memory and storage	4GB RAM; 64GB internal storage; microSD up to 2TB
Wireless	2.4/5GHz Wi-Fi; two-way Bluetooth 5.0
Bluetooth transmit codecs	SBC, AAC, aptX, aptX HD, LDAC, LHDC
Bluetooth receive codecs	SBC, AAC, aptX, aptX HD, aptX LL, LDAC, aptX Adaptive
Battery	6200mAh
Rated battery life	Approx. 10.5h single-ended / 9h balanced
Charging time	Approx. 3.5h
Dimensions	Approx. 140 × 80 × 18.9mm
Weight	Approx. 345g

What's in the box, manuals and downloads

• FiiO M15S ×1
• Leather Case ×1
• DK3S Heat Dissipation Dock ×1
• PD Charging/Data Cable ×1
• USB Power Cable for DK3S ×1
• USB Adapter ×1
• Quick Start Guide ×1
• Warranty Card ×1
• Tip Card ×1
• microSD Card Removal Pin ×1
• GPL Manual ×1

Visit the EMiUZEK download center.

Additional Product Content

FiiO M15S vs M23: which should you choose?

Feature	FiiO M15S	FiiO M23
DAC architecture	ES9038PRO	AK4191EQ + AK4499EX
Desktop power connection	Shared USB-C connection	Separate USB-C POWER IN
Maximum balanced power at 32Ω	1200mW + 1200mW	1000mW + 1000mW
Wired headphone outputs	3.5mm, 2.5mm and 4.4mm	3.5mm and 4.4mm
Weight	Approx. 345g	Approx. 299g for the aluminium version
Best reason to choose	2.5mm support, higher maximum 32Ω balanced power and ES9038PRO design	Lighter aluminium body, separate power input and AKM-based architecture