Fiio M21

The Fiio M21 packs a quad DAC, fully balanced architecture into a genuinely pocketable 193g body. Four Cirrus Logic CS43198 chips run in an eight channel differential layout, driven by a Snapdragon 680 on Android 13, so streaming apps feel quick and playback stays bit perfect.

It is the mid range sweet spot of FiiO's current player lineup: small enough for a jacket pocket, yet with a Super High Gain mode and desktop trick borrowed from the flagships.

Type and Technology

The M21 uses four CS43198 DACs in a fully differential configuration feeding a two stage amplifier built from OPA1692 voltage amps and SGM8262 current buffers. FiiO's DAPS architecture keeps Android from resampling your music, All To DSD and MQA 8x decoding are on board, and the 3.5mm socket doubles as a low jitter coaxial output. Dual USB C ports separate data from power, enabling the patented battery bypass desktop mode, and Super High Gain engages a higher voltage rail when external power is connected for up to 950mW per channel balanced.

Sound Character

The presentation is clean, transparent, and well balanced with a subtle touch of warmth that keeps long sessions musical rather than sterile. Bass is tight, quick, and controlled, treble is energetic and extended without fatigue, and resolution and background blackness are standouts for its class.

Build and Features

A 4.7 inch 750 x 1334 display keeps the footprint at roughly 121 x 68 x 17mm, in Titanium Gold, Dark Blue, or Black. The 4000mAh battery runs about 15 hours single ended or 12.5 hours balanced and recharges quickly over 20W PD. Two way Bluetooth handles LDAC in both directions plus aptX HD and LHDC transmission, WiFi covers AirPlay, DLNA, and FiiO Link, and microSD cards up to 2TB expand the 64GB of internal storage. An RGB indicator, HOLD switch, customizable function key, and the optional SK-M21C cassette style case with matching retro interface add personality.

Best For

Listeners stepping up from a phone and dongle who want a dedicated pocket player with real balanced power. Compare it with the rest of our digital audio players and other portable gear, or explore the whole Fiio collection.

What's in the Box

• Fiio M21 player
• Protective case
• Screen protector (pre installed)
• USB C data cable
• Quick start guide and warranty card

Specifications

What Reviewers Say

Reviews By WaveTheory highlights the M21's ample balanced power for driving full size headphones at its price in his hands-on review.