SMSL SH-9 Headphone Amplifier: THX AAA-888

Features

*THXAAA-888 Headphone Amplfier with THX AAA Technology
*6 Watts into 16 Ohm,3 Watts into 32 Ohm Headphones with lowest THD+N
*0.1Hz to 500kHz(-3dB) Frequency Response 
*SNR>137dB
*THD<0.00006%
*Ultra-Compact Design, Perfect for Desktop Systems
*Balanced Stereo Headphone Output
*Balanced Stereo Line Input
*High Precision Resistors for Temperature Stability
*Pop-less Design with High-Quality Relays
*High precision and low noise 256 level relay volume control; In actual use, in order to make the volume more linear, the extra levels are shielded.
*2 Positions Switchable Gain Control
*Fully Protection with DC, Over-Voltage, Over-Current, Short-Circuit and  Thermal Protection on Headphone Amplifier
*High-Eficiency Ultra-Low-Noise Power Supply 
*1.9 inch LCD display.

Specifications

Audio Section:
Inputs:Balanced x1, Unbalanced x1
Outputs:Balanced x1, Unbalanced x1
Output Power:6W x 2(16Ω)
                       3W x 2(32Ω)
                       440mW x 2 (300Ω)
                       220mW x 2 (600Ω)
SNR:137dB, A-Weighted
Output Noise:1.9uV, A-Weighted
 THD+N:-123dB, 0.00006% (A-Weighted)
THD+N:-117dB, 0.00013% (20-20kHz, 32Ω,-3dB)
THD:-125dB, 0.00006%(1kHz, 16Ω, -3dB)
Input Impedance:47kΩ
Output Impedance:Near 0Ω
Frequency Response:0.1Hz-500kHz(-3dB)
Gain:Low(+0dB), High(+10dB)

General Section:
Power supply voltage/frequency: AC100-240V, 50-60 Hz
Power consumption(EN60065):24W
Power consumption in standby mode:<0.1W
Size:187.5x154x40(mm)
Packing size: 282x232x79(mm)
Weight:790g