I found the following specs for the HA-INFO DA1.
Size: 11.2cm x 4.8cm x 18cm (width x high x deep)
Dynamic Range: >110db
THD + N (total harmonic distortion plus noise): <0.003%
SNR > 100dB
Frequency Response: 20Hz---20KHz
Sampling Rate: USB input---16Bit 24bit 44.1K-96K; Coaxial or Optical input---16～24Bit 44.1K~192k;
Supported OS: Windows XP, VISTA, Win 7 and Mac, Plug & Play, no installing drivers or software.
Input Interface: USB, Coaxial, Optical .
Output Interface: Coaxial, Optical, RCA stereo line out and 6.35 stereo headphones output
Line-OUT: 2V RMS
HeadPhone-OUT: 5V RMS
Power Supply: input--100-240V 50/60Hz AC, output--DC18V 0.65A
Suitable Headphone Impedance 10 ohm---300 ohm
Item Include: DA1 DAC X1, USB cable X1, Power cableX1, User Manual X1.
LVP: AD OP275GS
Headphone Amplifier: Class A
Unfortunately I can't find any specs that tells me the power output (in mW) for the headphone impedance between 10 ohm to 300 ohms. Makes me suspicious that it's not much.
Also missing is the specifications for the output impedance to drive the headphones...I've got a low impedance HE-400 headphone and want to know if there's an impedance mismatch.
Note that the USB input is limited to no more than 96kHz - kind of a bummer.
I'm now thinking of up-grading to a better DAC, headphone amp and USB interface. Looking hard at the Audio-GD Compass 2.