FiiO Portable Smart High Res Audio Player - M33 R2R (B)


Qualcomm Snapdragon 680 | Android 13, 8GB+128GB large storage and RAM
XMOS XU316 chip | 10-band PEQ, supports AUTO EQ
Fully differential 24Bit R2R resistor arrays | Multi-stage audio circuit with TI op-amps
1100mW+1100mW powerful output
M27-derived proprietary DAPS Digital Audio Purification System
5.5-inch 1080p HD display | 15.5 hours of long battery life
*Pictures are for reference only. The actual product may vary.

Selling points
Qualcomm Snapdragon 680 Android13, 8GB+128GB large storage and RAM
XMOS XU316 chip
Fully differential 24Bit R2R
resistor arrays
Multi-stage audio
circuit with TI op-amps
M27-derived proprietary DAPS Digital Audio Purification System
10-band PEQ,
supports AUTO EQ
Ultra-long battery life
fast charging
Next-gen minimalist design with clean lines
5.5-inch large HD display
Generous storage and memory combination compared to other devices in its class.
Synchronizes audio
and video.
Provides consistent audio-visual experiences.
Combines the rich, analog-like warmth unique to R2R with the qualities of a well-balanced, high-end audio source.
1100mW+1100mW balanced output power Easily drive your headphones.
A significant leap in digital audio processing efficiency and quality.
Headphone curve automatic matching.
1.5h to fully charge
13.5h of balanced playback
15.5h of single-ended playback
A comfortable, lightweight, yet stunning device with 18:9 aspect ratio and weighing only 258g.
Compatible with the RETRO BOX cassette- style Bluetooth speaker
Supports LDAC Bluetooth, features 5W*2 full-range output.
*RETRO BOX is not included and must be purchased separately.
Brand new cassette tape,
spectrum, and VU meter
themes make every song
more immersive and engaging.

From desktop to portable
The evolution of R2R
Fully differential 24Bit R2R resistor arrays DAC
Four channels, a total of 192 precision thin-film
resistors with 0.1% accuracy and low temperature drift.
We’ve taken our proprietary R2R resistor array originally designed for desktop equipment, and brought it over to a portable player for the first time. Shaped by the ears of expert acoustic engineers and perfected through feedback from the global audiophile community, it delivers the ultimate listening experience:
The unmistakable, lush analog warmth traditionally associated with R2R combined with balanced, high-fidelity performance.

Extensive storage
Enduringly smooth performance
The Qualcomm Snapdragon 680 and an expansive 8GB RAM + 128GB ROM storage featured in the M33 R2R is unmatched in its class. Experience effortless streaming and seamless multitasking. It offers extra performance and storage to easily handle any future updates as well as to ensure a stable and durable experience for years to come.

Perfect USB DAC audio-visual sync
Powered by a dedicated “core”
Frustrated by high latency when using a USB DAC for songs or videos?
A dedicated XMOS XU316 chip provides ultra-low latency and robust performance, ensuring flawlessly synchronized audio that stays consistent across all your devices.

Large 5.5-Inch HD Display
Beyond just size
Experience total immersion with a high-definition display designed for high-fidelity entertainment. New cassette tape, spectrum, and VU meter visuals pull you deeper into the music and give every track a classic retro flair.

Ultra-slim comfort, Stunning at first touch
Minimalist design
Dual-beveled edging
AG matte glass back panel
Weight
Thickness
Width
Like with the minimalist design featured on the FIIO M21, the sleek, refined lines of the M33 R2R create a sophisticated aesthetic. Clever engineering allows us to strike the perfect balance between size and ergonomics. It's not just about the impressive numbers on the M33 R2R’s spec sheet, it’s about that seamless, natural feel in your hand.
18:9 Golden ratio
Perfect grip
Clean and premium
Ergonomic comfort
Silky smooth feel

Flagship-grade proprietary DAPS (Digital Audio Purification System)
High-Capacity FPGA + Dual Custom Femtosecond Crystal Oscillators
The M33 R2R is equipped with the same ultra-high precision, ultra-low jitter unified clock source found in the flagship M27, providing a massive leap in digital audio processing efficiency and fidelity compared to the M23.

Supports AUTO EQ
Your ideal sound, just a tap away
Find manually adjusting the 10-band lossless PEQ too complex?
AUTO EQ automatically matches your headphone’s frequency curve, delivering your ideal sound profile instantly with lossless precision. In addition to sound presets such as pop, jazz and classical, the app also supports granular, per-band customization – allowing you to personally tune your own sound.

Carefully engineered audio circuit
Powered by TI
The pre-amp stage utilizes TI fully differential op-amps for I/V conversion and signal conditioning, delivering a natural and expansive soundstage. The output stage features quad INA1620 amp chips in a parallel configuration. Thanks to these chips, the result is output power up to 1100mW+1100mW to effortlessly drive any headphone. Finally, the precision electronic volume control ensures that you experience explosive dynamics without losing a hint of detail.

High-End audiophile components
2x TI Burr-Brown OPA1637 fully differential audio op-amps
4× Ti Burr-Brown INA1620
8x Rubycon film capacitors
NJW1195A precision volume controller
Explosive dynamics and masterful control over every note.
Minimizes crosstalk, ensuring no inter-channel interference even during overdrive or clipping conditions.
Achieves natural, transparent mids and smooth, fatigue-free treble.
Provides high precision and ultra-low noise for accurate volume adjustment.

Precision power supply system
65A High-Current MOSFETs for efficient power routing with minimal loss
Massive capacitors for energy storage
15W Power management system with ample power headroom
There are independent power supplies for digital and analog stages. The analog stage utilizes three separate power circuits for the R2R array, pre-amp, and amp stages, ensuring a more refined and natural sound signature.
The amp power supply supports two voltage tiers. Activating "Super High Gain Mode" triggers the high-voltage rail, boosting output power to 1100mW+1100mW that allows it to effortlessly drive everything from sensitive IEMs to demanding over-ear headphones.

Multi-Stage Partitioned Shielding
Restoring pure sound
To ensure the cleanest audio possible, the digital audio processing, R2R array, amp, and power modules are housed in separate zones with independent shielding. This significantly reduces signal interference and crosstalk, resulting in a "blacker", ultra-silent background with a clearer soundstage where every musical detail shines through.

15.5 Hours of ultra-long battery life
Say goodbye to power anxiety
Battery capacity
Low-temperature fast charging
Fully charged
Single-ended playback
Balanced playback
*Data from FIIO Labs. Actual performance may vary depending on usage and environmental factors.
Featuring a premium 4400mAh high-capacity battery, both single-ended and balanced playback times are significantly improved over the M23. Low-temperature fast charging means the M33 R2R powers up quickly without overheating. Between the long-lasting battery and rapid charging, your music never has to stop.

double relay lossless transmission
Dual Type-C ports, Double the versatility
Patented desktop mode
PSuper High Gain Mode
Bypasses the battery during use to handle high-power output without drain. This reduces charge/discharge cycles to significantly extend battery lifespan.
Patent number: ZL202321946664.8
Equipped with four gain levels: Low, Medium, High, and Super High Gain Mode. Connect a fast charger to either Type-C port to activate Over-Ear Headphone mode, unlocking even more gain and output power. With an output of up to 1100mW+1100mW per channel, it easily drives demanding, high-impedance over-ear headphones.
32Ω,Balanced, Super High Gain Mode
32Ω,Single-ended, Super High Gain Mode

Total Versatility, Wide Compatibility
Analog Outputs
3.5mm+4.4mm headphone outputs
3.5mm+4.4mm line outputs
SPDIF output
USB Audio output
Digital outputs
SBC/aptX/aptX HD/LHDC/LDAC
Two-way high-res Bluetooth
SBC/LDAC
Supports single-ended and balanced headphones.
With dedicated line-amp circuitry, connect to external speakers and amps to truly experience the magic of R2R sound.
Connect to external DACs or pair with the DK1PRO to instantly transform the device into a high-performance streaming transport.
Features a low-jitter coaxial signal processing circuit that rivals dedicated digital transports, with coaxial output jitter as low as 71.5ps. Pair with high-end external DACs for truly remarkable performance.
Bluetooth transmission supports:
Bluetooth reception supports:

Compatible with RETRO BOX
Bring your own soundtrack wherever
*RETRO BOX is not included and must be purchased separately.
It is the perfect match for the RETRO BOX cassette-style Bluetooth speaker, opening up another way to enjoy music. The versatile UI of the RETRO BOX allows it to serve as both a decorative desktop centerpiece and your portable soundtrack source.

Total versatility, Wide compatibility
Five operating modes
Customizable multi-function buttons
Leather protective case included
Choose between Android, Pure Music, AirPlay, USB DAC, and Bluetooth reception modes.
One-click access to functions that you frequently use.
The retro gold version comes with a khaki leather case, while the dark blue and black versions come with a color-matching leather case.

Packing List
①--------------------------------------------------------M33 R2R*1
②--------------Leather case (pre-installed onto device) *1
③------------------------------------------------USB data cable*1
④---------------------------------------------Quick start guide*1
⑤--------------------------------------------------Warranty card*1
⑥------------------------------------------------GPL V2 manual*1
⑦----------Screen protector (pre-applied onto device) *1
| General Specifications | |
|---|---|
| Name/Model | M33 R2R |
| Hardware solution | SoC: Qualcomm Snapdragon 680, DAC: FIIO proprietary R2R DAC, USB DAC: XU316; |
| Working modes | Android/Pure Music/AirPlay/USB DAC/Bluetooth reception |
| Colors | Retro gold/dark blue/black |
| Weight | About 258g |
| Dimensions | About 138.2x71.5x17mm |
| Volume control | Button control |
| Display | 5.5-Inch (1080x2160) fully laminated screen |
| Internal storage/Usable storage (ROM) | 128GB/About 112GB |
| Memory (RAM) | 8GB |
| Recommended headphone impedance | PO: 8~350Ω |
| Memory card | Supports up to 2TB |
| Channel balance | L20~R20 (0.5dB per level) |
| Gain selection | Over-ear headphone mode (Connect a fast charger)/High/Medium/Low |
| Buttons and ports | |
| Buttons | Power button*1, Volume button*2, Multifunction button*1, Play/Pause button*1, Previous track*1, Next track*1 |
| USB | Type-C USB3.0*1 (Charging/Data transfer)+Type-C POWER IN*1 (Charging/Independent power supply interface) |
| Slide switch | D.MODE button*1 |
| Headphone output | Standard 3.5mm port |
| Line output | Standard 3.5mm port (shared PO) |
| Coaxial output | Standard 3.5mm port (shared PO) |
| Balanced headphone output | Standard 4.4mm port |
| Balanced line output | Standard 4.4mm port (shared BAL) |
| Special Functions | |
| WiFi | 2.4GHz/5GHz, DLNA/AirPlay/WiFi music transfer |
| Bluetooth transmission (5.0) | SBC/aptX/aptX HD/LDAC/LHDC |
| Bluetooth reception (5.0) | SBC/LDAC |
| Remote control | Supports WiFi control |
| MQA | Supports global decoding |
| ALL TO DSD | Yes |
| PEQ | Supports 10-band PEQ and AUTO EQ |
| Sound profiles | Natural sound/Warmer sound |
| Double click to wakeup | Yes |
| Screen rotation | Yes |
| Operation | Supports gesture control, two-button and three-button navigation. |
| Power-off timers | Supports idle poweroff/sleep |
| Maximum sampling rates | Local DAC: Supports up to 384kHz/32bit; DSD256 (Native), USB DAC: Supports up to768kHz/32bit; DSD512 (Native), USB Audio: 768kHz/32bit; DSD512 (Supports DoP/D2P/Native), Coaxial output: Supports up to 384kHz/24bit; DSD128 (DOP/D2P) |
| Firmware update | Supports local storage upgrade+microSD card local upgrade+OTA push upgrade |
| Power Supply Parameters | |
| Power supply | PD2.0/PD3.0 PPS fast charging |
| Charging time | About 1.5h (PD3.0 PPS fast charging) |
| Power Supply Parameters - Battery life and test conditions: - 3.5mm headphone output: 15.5h | |
| Volume level | 43 |
| Gain | High gain |
| Display status | OFF |
| Playback track and format | MP3 44kHz/16bit |
| EQ | OFF |
| Load | 32Ω |
| Personalized sound | Natural sound: NOS |
| Power Supply Parameters - Battery life and test conditions: - 4.4mm balanced output: 13.5h | |
| Volume level | 31 |
| Gain | High gain |
| Display status | OFF |
| Playback track and format | MP3 44kHz/16bit |
| EQ | OFF |
| Load | 32Ω |
| Personalized sound | Natural sound: NOS |
| Audio Parameters - Performance and parameters of headphone output (3.5mm output, Local playback/USB DAC, Natural sound, Over-ear headphone mode) | |
| Output power 1 | L+R≥540mW+540mW (16Ω, THD+N<1%, 2.9Vrms) |
| Output impedance | <0.8Ω (32Ω) |
| Output power 2 | L+R≥470mW+470mW (32Ω, THD+N<1%, 3.9Vrms) |
| Crosstalk | ≥74dB (1kHz@32Ω) |
| Output power 3 | L+R≥60mW+60mW (300Ω, THD+N<1%, 4.2Vrms) |
| Noise floor | <5.5μV (A-weighted) |
| THD+N | PCM: 0.0183% |
| SNR | ≥117dB (A-weighted) |
| DSD: 0.0033% | Dynamic range |
| Frequency response | 20Hz~20kHz: attenuation<1.3dB |
| Peak output voltage | >12Vp-p |
| Audio Parameters - Performance and parameters of headphone output (3.5mm output, Local playback/USB DAC, Natural sound, Over-ear headphone mode) - Performance and parameters of headphone output (3.5mm output, Local playback/USB DAC, Natural sound, High gai | |
| Output power 1 | L+R≥465mW+465mW (16Ω, THD+N<1%, 2.7Vrms) |
| Output impedance | <0.8Ω (32Ω) |
| Output power 2 | L+R≥300mW+300mW (32Ω, THD+N<1%, 3.1Vrms) |
| Crosstalk | ≥74dB (1kHz@32Ω) |
| Output power 3 | L+R≥50mW+50mW (300Ω, THD+N<1%, 3.9Vrms) |
| Noise floor | <4.9μV (A-weighted) |
| THD+N | PCM: 0.0186% |
| SNR | ≥116dB (A-weighted) |
| DSD: 0.0033% | Dynamic range |
| Frequency response | 20Hz~20kHz: attenuation<1.3dB |
| Peak output voltage | >10Vp-p |
| Audio Parameters - Performance and parameters of headphone output (3.5mm output, Local playback/USB DAC, Natural sound, Over-ear headphone mode) - Performance and parameters of single-ended line output (3.5mm output, Local playback/USB DAC, Natural sound) | |
| THD+N | PCM: 0.0182% |
| SNR | ≥116dB (A-weighted) |
| DSD: 0.0034% | Noise floor |
| Crosstalk | ≥103dB |
| Dynamic range | ≥104dB |
| Frequency response | 20Hz~20kHz: attenuation<1dB |
| Line output level | 2Vrms (1kHz@10kΩ) |
| Audio Parameters - Performance and parameters of headphone output (3.5mm output, Local playback/USB DAC, Natural sound, Over-ear headphone mode) - Performance and parameters of balanced headphone output (4.4mm output, Local playback/USB DAC, Natural sound | |
| Output power 1 | L+R≥540mW+540mW (16Ω, THD+N<1%, 2.9Vrms) |
| Output impedance | <1.5Ω (32Ω) |
| Output power 2 | L+R≥1100mW+1100mW (32Ω, THD+N<1%, 6Vrms) |
| Crosstalk | ≥104dB (1kHz@32Ω) |
| Output power 3 | L+R≥240mW+240mW (300Ω , THD+N<1%, 8.5Vrms) |
| Noise floor | <10.3μV (A-weighted) |
| THD+N | PCM: 0.0171% |
| SNR | ≥116dB (A-weighted) |
| DSD: 0.0033% | Dynamic range |
| Frequency response | 20Hz~20kHz: attenuation<1.3dB |
| Peak output voltage | >24Vp-p |
| Output power 1 | L+R≥540mW+540mW (16Ω, THD+N<1%, 2.9Vrms) |
| Output impedance | <1.5Ω (32Ω) |
| Output power 2 | L+R≥900mW+900mW (32Ω, THD+N<1%, 5.4Vrms) |
| Crosstalk | ≥104dB (1kHz@32Ω) |
| Output power 3 | L+R≥165mW+165mW (300Ω , THD+N<1%, 7Vrms) |
| Noise floor | <9.1μV (A-weighted) |
| THD+N | PCM: 0.0180% |
| SNR | ≥116dB (A-weighted) |
| DSD: 0.0033% | Dynamic range |
| Frequency response | 20Hz~20kHz: attenuation<1.3dB |
| Peak output voltage | >20Vp-p |
| Audio Parameters - Performance and parameters of headphone output (3.5mm output, Local playback/USB DAC, Natural sound, Over-ear headphone mode) - Performance and parameters of balanced line output (4.4mm output, Local playback/USB DAC, Natural sound) | |
| THD+N | PCM: 0.0163% |
| SNR | ≥118dB (A-weighted) |
| DSD: 0.0034% | Noise floor |
| Crosstalk | ≥105dB |
| Dynamic range | ≥114dB |
| Frequency response | 20Hz~20kHz: attenuation<1dB |
| Line output level | 4Vrms (1kHz@10kΩ) |
| Audio format supported | |
| Lossless: | DSD: DSD64/128/256 (".iso", ".dsf", ".dff"), DST iSO DXD: 352.8kHz/24bit APE FAST/High/Normal: 384kHz/24bit (MAX) APE Extra High: 192kHz/24bit (MAX) APE Insane: 96kHz/24bit (MAX) Apple Lossless: 384kHz/32bit (MAX) AIFF: 384kHz/32bit (MAX) FLAC: 384kHz/32bit (MAX) WAV: 384kHz/32bit (MAX) WMA LOSSLESS: 96kHz/24bit (MAX) |
| Lossy compression: | MP3, OGG, WMA, etc. |


