General Specifications
Name/Model DM15 Hardware Scheme SoC: GD32F305RET6, Op-amp: SGM8262*2, DAC: AK4493SEQ*2, Bluetooth: QCC3086, USB chip: SPV5048
Working mode CD playback/USB DAC mode/Bluetooth transmitter mode
Color White/Black/Red/Silver Weight About 471.5g
Dimensions About 144x137x25.5mm (excl. feet and knob) Volume Control Type Knob control
Display 0.96 inch (80x 160)LCD display Laser pickup Custom laser pickup
Recommended headphone impedance PO:8~350Ω Mechanism Custom mechanism
BAL:8~350Ω 　 　
Buttons and Ports
Buttons Power button*1; Stop button*1; Play/Pause button*1; Previous track button*1; Next track button*1; EQ button*1; Volume knob with button*1 USB Type-C USB2.0*1 (Data transfer) +Type-C POWER IN*1 (Charging/Dedicated power supply port)
Headphone output interface Standard 3.5mm port Balanced headphone output Standard 4.4mm port
Linear Output Interface Standard 3.5mm port Balanced line output Standard 4.4mm port
coaxial output interface Standard 3.5mm port (shared LO) Optical output Standard 3.5mm port (shared LO)
ripple switch Input selector switch*1+Output selector switch*1+BASS switch*1+ESP switch*1+D.MODE switch*1 　 　
Special Functions
Bluetooth transmission (5.4) SBC/aptX/aptX HD/aptX LL/aptX Adaptive/aptX Lossless CD ripping mode Support
BASS OFF/1/2 Sleep Timer Support
EQ Adjustment 8 preset EQ modes Drive-free mode (Switch mode) Support
 Sampling rate USB DAC: Up to 384kHz/32bit; DSD256 (Native) Firmware update USB upgrade/Local upgrade
Coaxial output: Up to192kHz/24bit 　 　
Optical output: Up to 96kHz/24bit 　 　
 Power Supply Parameters
Power supply Supports QC3.0, PD2.0 and PD3.0 fast charging Charging time About 2h (PD3.0 fast charging)
CD Battery Life and Test Conditions:
3.5mm headphone output: 6h
Volume level 24 BASS OFF
Display status OFF ESP ON
EQ OFF D.MODE OFF
Load 32 Ω 　 　
4.4mm balanced headphone output: 6h
Volume level 18 BASS OFF
Display status OFF ESP ON
EQ OFF D.MODE OFF
 Load 32 Ω 　 　
USB DAC Battery Life and Test Conditions:
3.5mm headphone output: 9h
Volume level 24 BASS OFF
Display status OFF ESP OFF
EQ OFF D.MODE OFF
Load 32 Ω 　 　
4.4mm balanced output: 9h
Volume level 18 BASS OFF
Display status OFF ESP OFF
EQ OFF D.MODE OFF
Load 32 Ω 　 　
Audio Parameters
Performance and parameters of headphone output (3.5mm output, BASS OFF, ESP OFF)

D.MODE ON

Output power

 L+R≥545mW+545mW (16Ω,THD+N<1%,3Vrms) Output impedance <1Ω
L+R≥295mW+295mW (32Ω,THD+N<1%,3.1Vrms) Crosstalk ≥ 73dB
L+R≥35mW+35mW (300Ω,THD+N<1%,3.2Vrms) Noise floor <3.4uV(A weight)
D.MODE OFF Output power L+R≥380mW+380mW (16Ω,THD+N<1%,2.5Vrms) SNR ≥ 119dB (A-weighted)
L+R≥205mW+205mW (32Ω,THD+N<1%,2.6Vrms) Dynamic range ≥ 119dB (A-weighted)
L+R≥25mW+25mW (300Ω,THD+N<1%,2.7Vrms) Peak output voltage 9Vp-p
Frequency response 20Hz to 70kHz: Attenuation <2.9dB(UAC) THD+N UAC:<0.00052%(1kHz/-6dB@32Ω)
20Hz ~ 20KHz: Attenuation <0.3dB(UAC) CD:<0.0013%(1kHz/-2dB@32Ω)
20Hz ~ 20KHz: Attenuation <1.5dB(CD)    
 Performance and parameters of balanced headphone output (4.4mm output, BASS OFF, ESP OFF)

D.MODE ON

output power

 L+R≥700mW+700mW (16Ω,THD+N<1%,3.4Vrms) Output impedance <1.5Ω
L+R≥1100mW+1100mW (32Ω,THD+N<1%,6Vrms) Crosstalk ≥ 116dB
L+R≥135mW+135mW (300Ω,THD+N<1%,6.3Vrms) Noise floor <4.6uV(A weight)
D.MODE OFF output power L+R≥700mW+700mW (16Ω,THD+N<1%,3.4Vrms) SNR ≥ 122dB (A-weighted)
L+R≥780mW+780mW (32Ω,THD+N<1%,5Vrms) Dynamic range ≥ 122dB (A-weighted)
L+R≥95mW+95mW (300Ω,THD+N<1%,5.3Vrms) Peak output voltage 18Vp-p
Frequency response 20Hz to 70kHz: Attenuation <2.9dB(UAC) THD+N UAC:<0.00047%(1kHz/-10dB@32Ω)
20Hz ~ 20KHz: Attenuation <0.3dB(UAC) CD:<0.0013%(1kHz/-5dB@32Ω)
20Hz ~ 20KHz: Attenuation <1.5dB(CD)    
Performance and parameters of line output (3.5mm output, BASS OFF, ESP OFF)
THD+N UAC:<0.00068%(1kHz/-5dB@10KΩ) Noise floor <2.4uV(A weight)
CD:<0.0014%(1kHz/-2dB@10KΩ) SNR ≥ 119dB(A-weighted)
Crosstalk ≥ 110dB Dynamic range ≥ 119dB(A-weighted)
 Frequency response 20Hz to 85kHz: Attenuation <2.4dB(UAC) D.MODE ON Line output level 2Vrms(1KHz @ 10kΩ)
20Hz ~ 20KHz: Attenuation <0.2dB(UAC) D.MODE OFF Line output level 1.7Vrms(1KHz@10kΩ)
20Hz ~ 20KHz: Attenuation <1.4dB(CD)    
Performance and parameters of balanced line output (4.4mm output, BASS OFF, ESP OFF)
 THD+N UAC: ＜0.0004% (1kHz/-7dB@10KΩ) Noise floor <2.9uV(A weight)
CD: ＜0.0013% (1kHz/-1dB@10KΩ) SNR ≥ 123dB (A-weighted)
Channel separation ≥ 112dB Dynamic range ≥ 123dB (A-weighted)
Frequency response 20Hz~85kHz: attenuation＜2.4dB (UAC) D.MODE ON Line output level 4Vrms(1KHz @ 10kΩ)
20Hz~20KHz: attenuation＜0.2dB (UAC) D.MODE OFF Line output level 3.4Vrms(1KHz@10kΩ)
20Hz~20KHz: attenuation＜1.4dB (CD)