General Specifications
Name/Model DM15 R2R Hardware Scheme

Master control: GD32F305RET6, op-amp: SGM8262*2,

DAC: FIIO proprietary R2R DAC, Bluetooth: QCC3095,

USB chip: SPV5048
Working mode CD playback/USB DAC mode/Bluetooth transmitter mode
Color White/Black/Red/Silver Weight About 471.5g
Dimensions About 144x 137x 25.5mm (not including foot pads and knobs) Volume Control  Knob
Display 0.96 inch (80x 160)LCD display Laser pickup Custom laser pickup
Adaptive impedance PO:8~350Ω Mechanism Custom mechanism
BAL:8~350Ω 　 　
 Buttons and Ports
Buttons Power*1; Stop*1; Play/Pause*1; Previous track*1; Next track*1; EQ*1; USB

Type-C USB2.0 * 1 (data transfer) +

Type-C POWER IN * 1 (charging/independent

power supply interface)
Headphone output Standard 3.5mm socket Balanced output standard 4.4mm socket
Line output Standard 3.5mm socket Balanced line output standard 4.4mm socket
Coaxial output Standard 3.5mm socket (multiplexed with LO port) Optical output standard 3.5mm socket (multiplexed with LO port)
Slide switch Input switch button * 1 + output switch button * 1 + BASS switch * 1 + ESP switch * 1 + D.MODE switch * 1   　
 Special function
Bluetooth transmission (5.4) SBC/aptX/aptX-HD/aptX-LL/aptX-Adaptive Operation mode Button/Knob
BASS BASS OFF/1/2 Timing Shutdown Supported
EQ Adjustment built-in 8 kinds of preset EQ Drive-free mode Supported
Maximum supported sampling rate USB DAC: Up to 384kHz/32bit; DSD256 (Native) Firmware Upgrade USB Upgrade/Local Upgrade
Coaxial output: Up to 192kHz/24bit 　 　
Optical output: Up to 96kHz/24bit 　 　
 Power Supply Parameters
Power supply Supports PD2.0 and PD3.0 fast charge Charging time About 2 hours (PD3.0 fast charge)
 CD playback mode battery life and test conditions
 3.5mm headphone output: 7 hours 
Volume 59 BASS OFF
Display state OFF ESP ON
EQ OFF D.MODE OFF
load 32 Ω 　 　
 4.4mm balanced headphone output: 7 hours
Volume 53 BASS OFF
Display state OFF ESP ON
EQ OFF D.MODE OFF
Load 32 Ω 　 　
USB decoding mode battery life and test conditions
 3.5mm headphone output: 11 hours
Volume 59 BASS OFF
screen status OFF ESP OFF
EQ OFF D.MODE OFF
load 32 Ω 　 　
4.4mm balanced headphone output: 10.5 hours
Volume 53 BASS OFF
screen status OFF ESP OFF
EQ OFF D.MODE OFF
load 32 Ω 　 　
 Audio Parameters
 Performance and parameters of headphone output (3.5mm output, USB DAC, OS mode, desktop mode)
Output power L+R≥575mW+575mW (16Ω,THD+N<1%,3.1Vrms) Output impedance <1Ω
L+R≥315mW+315mW (32Ω,THD+N<1%,,3.2Vrms) Crosstalk ≥ 72dB
L+R≥35mW+35mW (300Ω,THD+N<1%,3.3Vrms) Peak output voltage 9.5Vp-p
SNR ≥ 111dB (A-weighted) THD+N <0.025%(1kHz/-6dB @ 32Ω)
Frequency response 20Hz ~ 80kHz: Attenuation <2.9dB Noise floor <8.7uV(A weight)
20Hz ~ 20KHz: attenuation <0.2dB Dynamic range ≥ 106dB (A-weighted)
 Performance and parameters of headphone output (3.5mm output, USB DAC, OS mode)
Output power L+R≥405mW+405mW (16Ω,THD+N<1%,2.5Vrms) Output impedance <1Ω
L+R≥220mW+220mW (32Ω,THD+N<1%,,2.7Vrms) Crosstalk ≥ 72dB
L+R≥25mW+25mW (300Ω,THD+N<1%,2.8Vrms) Peak output voltage 7.9Vp-p
signal-to-noise ratio ≥ 111dB (A-weighted) THD+N <0.025%(1kHz/-6dB @ 32Ω)
Frequency response 20Hz ~ 80kHz: Attenuation <2.9dB Noise floor <7.5uV(A weight)
20Hz ~ 20KHz: attenuation <0.2dB Dynamic range ≥ 106dB (A-weighted)
 Performance and parameters of balanced headphone output (4.4mm output, USB DAC, OS mode, desktop mode)
Output power L+R≥480mW+480mW (16Ω,THD+N<1%,2.8Vrms) Output impedance <1.5Ω
L+R≥1150mW+1150mW (32Ω,THD+N<1%,6.1Vrms) Crosstalk ≥ 100dB
L+R≥145mW+145mW (300Ω,THD+N<1%,6.6Vrms) Peak output voltage 18.8Vp-p
SNR ≥ 112dB (A-weighted) THD+N <0.025%(1kHz/-6dB @ 32Ω)
Frequency response 20Hz ~ 70kHz: Attenuation <3dB Noise floor <14.7uV(A weight)
20Hz ~ 20KHz: attenuation <0.3dB Dynamic range ≥ 107dB (A-weighted)
 Performance and parameters of balanced headphone output (4.4mm output, USB DAC, OS mode)
Output power L+R≥545mW+545mW (16Ω,THD+N<1%,2.9Vrms) Output impedance <1.5Ω
L+R≥815mW+815mW (32Ω,THD+N<1%,5.1Vrms) Crosstalk ≥ 100dB
L+R≥100mW+100mW (300Ω,THD+N<1%,5.5Vrms) Peak output voltage 15.8Vp-p
SNR ≥ 112dB (A-weighted) THD+N <0.025%(1kHz/-6dB @ 32Ω)
Frequency response 20Hz ~ 80kHz: attenuation <2.9dB Noise floor <12.7uV(A weight)
20Hz ~ 20KHz: attenuation <0.2dB Dynamic range ≥ 107dB (A-weighted)
 Performance and parameters of line output (3.5mm output, USB DAC, OS mode, desktop mode)
THD+N <0.025%(1kHz/-6dB @ 10KΩ) SNR ≥ 111dB(A-weighted)
Crosstalk ≥ 100dB Noise floor <9.2uV(A weight)
Frequency response 20Hz ~ 80kHz: attenuation <2.9dB Line Output Level 3.3Vrms(1KHz@10kΩ)
20Hz ~ 20KHz: attenuation <0.2dB Dynamic range ≥ 106dB (A-weighted)
 Performance and parameters of line output (3.5mm output, USB DAC, OS mode)
THD+N <0.025%(1kHz/-6dB @ 10KΩ) SNR ≥ 111dB(A-weighted)
Crosstalk ≥ 100dB Noise floor <7.9uV(A weight)
Frequency response 20Hz ~ 80kHz: attenuation <2.9dB Line Output Level 2.8Vrms(1KHz@10kΩ)
20Hz ~ 20KHz: attenuation <0.2dB Dynamic range ≥ 106dB (A-weighted)
 Performance and parameters of balanced line output (4.4mm output, USB DAC, OS mode, desktop mode)
THD+N <0.025%(1kHz/-6dB @ 10KΩ) SNR ≥ 112dB (A-weighted)
Crosstalk ≥ 108dB Noise floor <15.6uV(A weight)
Frequency response 20Hz ~ 80kHz: attenuation <2.9dB Line Output Level 6.5Vrms(1KHz@10kΩ)
20Hz ~ 20KHz: attenuation <0.2dB Dynamic range ≥ 107dB (A-weighted)
 Performance and parameters of balanced line output (4.4mm output, USB DAC, OS mode)
THD+N <0.024%(1kHz/-6dB @ 10KΩ) SNR ≥ 112dB (A-weighted)
Crosstalk ≥ 108dB Noise floor <13uV(A weight)
Frequency response 20Hz ~ 80kHz: attenuation <2.9dB Line Output Level 5.4Vrms(1KHz@10kΩ)
20Hz ~ 20KHz: attenuation <0.2dB Dynamic range ≥ 107dB (A-weighted)
 Performance and parameters of line output (3.5mm output, CD, OS mode, desktop mode)
Output power L+R≥575mW+575mW (16Ω,THD+N<1%,3.1Vrms) Output impedance <1Ω
L+R≥315mW+315mW (32Ω,THD+N<1%,,3.2Vrms) Crosstalk ≥ 72dB
L+R≥35mW+35mW (300Ω,THD+N<1%,3.3Vrms) Peak output voltage 9.5Vp-p
SNR ≥ 110dB (A-weighted) THD+N <0.028%(1kHz/0dB @ 32Ω)
Dynamic range ≥ 94dB (A-weighted) Noise floor <9.7uV(A weight)
Frequency response 20Hz ~ 20KHz: attenuation <1.5dB 　 　
 Performance and parameters of line output (3.5mm output, CD, OS mode)
Output power L+R≥405mW+405mW (16Ω,THD+N<1%,2.5Vrms) Output impedance <1Ω
L+R≥220mW+220mW (32Ω,THD+N<1%,,2.7Vrms) Crosstalk ≥ 72dB
L+R≥25mW+25mW (300Ω,THD+N<1%,2.8Vrms) Peak output voltage 7.9Vp-p
SNR ≥ 109dB (A weight) THD+N <0.027%(1kHz/0dB @ 32Ω)
Dynamic range ≥ 94dB (A-weighted) Noise floor <8.5uV(A weight)
Frequency response 20Hz ~ 20KHz: attenuation <1.5dB 　 　
 Performance and parameters of balanced headphone output (4.4mm output, CD, OS mode, desktop mode)
Output power L+R≥480mW+480mW (16Ω,THD+N<1%,2.8Vrms) Output impedance <1.5Ω
L+R≥1150mW+1150mW (32Ω,THD+N<1%,6.1Vrms) Crosstalk ≥ 100dB
L+R≥145mW+145mW (300Ω,THD+N<1%,6.6Vrms) Peak output voltage 18.8Vp-p
SNR ≥ 112dB (A-weighted) THD+N <0.030%(1kHz/0dB @ 32Ω)
Dynamic range ≥ 94dB (A-weighted) Noise floor <14uV(A-weighted)
Frequency response 20Hz ~ 20KHz: attenuation <1.5dB 　 　
 Performance and parameters of balanced headphone output (4.4mm output, CD, OS mode)
Output power L+R≥490mW+490mW (16Ω,THD+N<1%,2.8Vrms) Output impedance <1.5Ω
L+R≥810mW+810mW (32Ω,THD+N<1%,5.1Vrms) Crosstalk ≥ 100dB
L+R≥100mW+100mW (300Ω,THD+N<1%,5.5Vrms) Peak output voltage 15.8Vp-p
SNR ≥ 110dB (A-weighted) THD+N <0.029%(1kHz/0dB @ 32Ω)
Dynamic range ≥ 94dB (A-weighted) Noise floor <13.6uV(A weight)
Frequency response 20Hz ~ 20KHz: attenuation <1.5dB 　 　
 Performance and parameters of line output (3.5mm output, CD, OS mode, desktop mode)
THD+N <0.028%(1kHz/0dB @ 10KΩ) SNR ≥ 110dB(A-weighted)
Crosstalk ≥ 100dB Noise floor <9.6uV(A weight)
Dynamic range ≥ 94dB (A-weighted) Line Output Level 3.3Vrms(1KHz@10kΩ)
Frequency response 20Hz ~ 20KHz: attenuation <1.5dB 　 　
 Performance and parameters of line output (3.5mm output, CD, OS mode)
THD+N <0.027%(1kHz/0dB @ 10KΩ) SNR ≥ 110dB(A-weighted)
Crosstalk ≥ 100dB Noise floor <8.5uV(A weight)
Dynamic range ≥ 94dB (A-weighted) Line Output Level 2.8Vrms(1KHz@10kΩ)
Frequency response 20Hz ~ 20KHz: attenuation <1.5dB 　 　
 Performance and parameters of balanced line output (4.4mm output, CD, OS mode, desktop mode)
THD+N <0.029%(1kHz/0dB @ 10KΩ) SNR ≥ 110dB (A-weighted)
Crosstalk ≥ 104dB Noise floor <18.4uV(A weight)
Dynamic range ≥ 94dB (A-weighted) Line Output Level 6.5Vrms(1KHz@10kΩ)
Frequency response 20Hz ~ 20KHz: attenuation <1.5dB 　 　
 Performance and parameters of balanced line output (4.4mm output, CD, OS mode)
THD+N <0.029%(1kHz/0dB @ 10KΩ) SNR ≥ 110dB (A-weighted)
Crosstalk ≥ 104dB Noise floor <15.8uV(A weight)
Dynamic range ≥ 94dB (A-weighted) Line Output Level 5.4Vrms(1KHz@10kΩ)
Frequency response 20Hz ~ 20KHz: attenuation <1.5dB