| General Specifications |
| Name/Model |
JM21 |
Hardware solution |
Main controller: Qualcomm Snapdragon 680; DAC: CS43198*2; Amp: SGM8262*2 |
| Working mode |
Android mode/Pure music mode/USB DAC mode/Bluetooth receiving mode |
| Color |
Sky blue |
Weight |
About 156g |
| Dimensions |
About 120.7x68x13mm |
Volume control |
Physical button |
| Display |
4.7-inch (750x1334) bezel-less display |
ROM/Usable storage |
32G ROM/22G ROM usable |
| RAM |
3GB |
Adaptive impedance |
PO: 8~150Ω |
| microSD card |
Single microSD card expansion, theoretically supports up to 2TB |
BAL: 8~350Ω |
| Channel balance |
L20~R20 (0.5dB per level) |
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| Buttons and Ports |
| Buttons |
Power on/off*1; Volume button*2; Play/Pause*1; Previous track*1; Next track*1 |
USB |
Type-C USB2.0*1 (Charging/Data transfer) |
| Headphone output |
Standard 3.5mm port |
Balanced headphone output |
Standard 4.4mm port |
| Coaxial output |
Standard 3.5mm port (shared PO) |
Line output |
Shared 3.5mm+4.4mm ports |
| Special functions |
| WiFi |
2.4GHz/5GHz, Supports DLNA, AirPlay, WiFi song transfer, etc. |
Bluetooth transmission (5.0) |
AAC/SBC/aptX/aptX HD/LDAC/LHDC |
| Bluetooth reception (5.0) |
SBC/AAC/LDAC |
FIIO Link |
Android supports WiFi and Bluetooth control, iOS supports Bluetooth control |
| Firmware upgrade |
Supports upgrading through local storage+microSD card+OTA |
Operation method |
Supports gesture, two-button and three-button operations |
| Max. supported sampling rate |
USB DAC: Up to 384kHz/32bit; DSD256 (Native) |
Poweroff timer |
Supports idle/sleep poweroff |
| Local decoding: Up to 384kHz/32bit; DSD256 (Native) |
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| USB Audio: 768kHz/32bit; DSD512 (DoP/D2P/Native supported) |
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| Coaxial output: Up to 384kHz/24bit; DSD128 (D2P/DOP) |
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| Power Supply Parameters |
| Power supply |
Supports 5V/≥2A |
Charging time |
About 2h (5V2A charger) |
| Battery life and test conditions: |
| 3.5mm headphone output: 12.5h |
| Volume |
49 |
Gain |
High gain |
| Display status |
OFF |
Playing track and format |
MP3 44kHz/16bit |
| EQ |
OFF |
Load |
32Ω |
| 4.4mm balanced headphone output: 9.5h |
| Volume |
38 |
Gain |
High gain |
| Display status |
OFF |
Playing track and format |
MP3 44kHz/16bit |
| EQ |
OFF |
Load |
32Ω |
| Audio Parameters |
| Performance and parameters of headphone output (3.5mm out, USB DAC, High gain) |
| Output power |
L+R≥360mW+360mW (16Ω, THD+N＜1%) |
Output impedance |
＜1Ω |
| L+R≥245mW+245mW (32Ω, THD+N＜1%) |
Crosstalk |
≥70dB |
| L+R≥30mW+30mW (300Ω, THD+N＜1%) |
Peak output voltage |
7.9Vp-p |
| SNR |
≥124dB (A-weighted) |
THD+N |
＜0.0012% (1kHz/-4dB@32Ω) |
| Frequency response |
20Hz~80kHz: attenuation＜0.7dB |
Noise floor |
＜1.6uV (A-weighted) |
| 20Hz~20KHz: attenuation＜0.02dB |
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| Performance and parameters of balanced headphone output (4.4mm out, USB DAC, High gain) |
| Output power |
L+R≥605mW+605mW (16Ω, THD+N＜1%) |
Output impedance |
＜1.5Ω |
| L+R≥700mW+700mW (32Ω, THD+N＜1%) |
Crosstalk |
≥110dB |
| L+R≥80mW+80mW (300Ω, THD+N＜1%) |
Peak output voltage |
13.2Vp-p |
| SNR |
≥129dB (A-weighted) |
THD+N |
＜0.0006% (1kHz/-4dB@32Ω) |
| Frequency response |
20Hz~80kHz: attenuation＜0.7dB |
Noise floor |
＜1.7uV (A-weighted) |
| 20Hz~20KHz: attenuation＜0.03dB |
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