FiiO M23 Portable High Resolution Music Player

The FiiO M23 is a portable hi-res lossless music player built around AKM’s flagship AK4191EQ + AK4499EX DAC combination and a fully balanced THX AAA 78+ amplifier with up to 1,000mW + 1,000mW. It was the first FiiO player with a dedicated Desktop Mode switch, and two USB-C ports, a 4-stage, 20-rail power supply, FiiO’s DAPS digital audio purification system and a 5,500mAh battery with safe 30W fast charging make it equally at home in your pocket and on your desk. Its awards include an EHA 2024 Gold Award and a VGP 2025 Summer Life Style Gold Award.

AKM’s flagship DAC combination

Like the Q15 and K9 AKM, the M23 uses AKM’s flagship AK4191EQ + AK4499EX. The design fully separates the digital and analogue sections and uses AKM’s “DWA ROUTING” technology to further improve the signal-to-noise ratio, for a purer background and higher resolution, with a relaxed yet natural sound.

THX AAA 78+: truly balanced, 8-way parallel amplification

The THX AAA 78 amplifiers of the M11 Plus and M11 Pro were widely praised by audiophiles. After several years of refinement, FiiO introduced the THX AAA 78+ architecture in the M23: a four-way fully balanced design with eight-way parallel amplification, for greater power with high fidelity and powerful sound reproduced with great accuracy.

The full audio chain runs from the DAC through I/V, low-pass filter and voltage amplification to the parallel amplification stage. Two low-noise, high-precision OPA1612 op-amps handle the I/V and low-pass stages, and two low-noise, high-bandwidth OPA1662 op-amps the voltage gain, so a huge variety of headphones and IEMs work well, dialled in with four gain levels. High-precision film resistors are used throughout the I/V, filter and THX stages, and eight Panasonic film capacitors in the low-pass filter keep the two channels and every frequency band consistent, for a detailed, stable sound. The digital core, DAC and amplifier sit in separately shielded zones to cut crosstalk and outside interference.

Super high gain: 1,000mW per channel

The M23 has two USB-C ports, one of them (POWER IN) dedicated to power. Connect a PD2.0 or PD3.0 fast charger and a fourth gain level, super high gain, appears: the balanced output rises from 475mW to 1,000mW per channel into 32Ω (and 240mW into 300Ω), and the 3.5mm output to 440mW, so the M23 can push high-impedance headphones. While POWER IN supplies the power, the other USB-C port draws no power from whatever is connected to it, which makes the M23 ideal as a USB DAC for a phone.

Patented Desktop Mode, at the flick of a switch

For the first time on a FiiO player, a dedicated switch turns on Desktop Mode (D.MODE, patent ZL202321946664.8). With it on, the M23 runs entirely from external power through either USB-C port, and the battery is neither charged nor discharged, so you can use it as desktop equipment without wearing out the battery. Any USB power supply works; it does not need to be a fast charger. If the battery falls below 15%, it charges until full.

A 4-stage, 20-rail power supply

FiiO’s experience with portable power supplies shows in a four-stage supply with 20 separate rails, a solid foundation for both the digital and analogue circuits. The digital and analogue supplies are independent; the analogue supply has separate rails for the DAC, small-signal and large-signal amplification, and four stages of processing (over-voltage protection, adaptive voltage regulation, high-efficiency boosting with π filtering, and LDO regulation), comparable to desktop equipment. Twenty-eight high-capacity polymer tantalum capacitors across the DAC, I/V, filter and THX supplies store energy for powerful sound.

5,500mAh with safe 30W fast charging

The battery uses specially selected low-resistance, fast-charging cells with high-temperature-resistant materials and a low-resistance MOS protection board for a long life. It plays for up to 10.5 hours from the 3.5mm output or 9 hours balanced. Dual-mode fast charging charges at up to 30W when the battery is low, then switches to gentler fast charging near full, to save time while protecting the battery: FiiO measures over 80% in about an hour and a full charge in about 2.5 hours with a PD3.0 charger. QC3.0, QC4.0, PD2.0 and PD3.0 PPS chargers are supported.

DAPS: bit-perfect playback in every app

FiiO’s DAPS (Digital Audio Purification System) combines FiiO’s own hi-fi audio core, which bypasses Android’s audio processing, with a low-jitter clock co-processor. It gives a unified, high-precision, low-jitter clock and keeps the original sample rate of PCM and DSD, whether you use FiiO Music, third-party apps or USB DAC mode, so nothing is resampled. A global 10-band PEQ with FiiO’s own algorithm works in every mode, letting you set each band’s frequency, gain, bandwidth and Q to fine-tune or correct your headphones’ response, alongside eight preset EQs; All to DSD also works in every mode.

Six working modes and full streaming

Switch between Android, Pure Music, USB DAC, Bluetooth receiver, AirPlay and Roon Ready modes. The Snapdragon 660, 4GB of RAM and 64GB of storage (about 46GB available), plus a microSD slot for cards up to 2TB, handle streaming apps and large libraries, and the M23 also plays music over DLNA and from a NAS, local network or cloud server through UPnP, SMB and WebDAV. Two-way Bluetooth 5.0 transmits LDAC, LHDC, aptX HD, aptX, AAC and SBC to wireless headphones and receives LDAC, AAC and SBC from a phone. An in-vehicle mode switches the M23 on and off with your car’s USB power.

Outputs for every set-up

The 3.5mm socket is a headphone output, a line output (2Vrms) or a coaxial output (up to 384kHz/24-bit and DSD128, with MQA); the 4.4mm socket is a balanced headphone or line output (4Vrms). Line-out volume can be fixed or adjustable. USB audio output feeds an external DAC at up to 768kHz/32-bit and DSD512, and as a USB DAC the M23 plays up to 384kHz/32-bit and DSD256. MQA is fully decoded (8x unfolding).

Classic design, built to last

FiiO’s classic hexagonal honeycomb design, with three-dimensional cuts and crisp edges, frames a 5.5-inch HD screen (1,440 × 720) in an 18:9 shape. The deep blue version is aluminium alloy (about 299g) with an electroplated tempered glass back; a stainless steel version is also made. Every port is reinforced with specially designed metal pieces, and the stainless steel battery compartment is strong and helps dissipate heat. Adjust the volume by sliding on the carbon-fibre-textured touch panel or with the buttons, assign a multifunction button, or control the M23 from your phone with FiiO Link (Wi-Fi or Bluetooth from Android, Wi-Fi from an iPhone). RGB lights follow the sample rate or a colour of your choice.

Good to know

• Super high gain needs a PD2.0/PD3.0 fast charger; other chargers charge normally (FiiO suggests 5V 1A or 2A). Desktop Mode works with any USB power supply.
• The USB 3.0 port handles data, charging, USB host and OTG; POWER IN is for power only.
• Line output is at full volume unless you enable adjustable line-out volume, so unplug headphones before switching to it.
• For R2R sound, see the FiiO M33 R2R; for a flagship with a bigger screen and more power, the FiiO M27.
• In the box: M23, water-resistant protective case, screen protector (fitted), USB-C cable, USB-A to USB-C adapter, tray eject pin, quick start guide, warranty card and GPL V2 manual.