A970 is a portable earphone power amplifier is a high performance the built-in high performance power processor and a power amplifier and can be connected with various audio player and mobile phone on the audio signal processing amplification the output can drive all types of headphones so as to enhance the audio amplifier power improve the quality of the amplification effect. Products can also be connected to the computer for sound amplification function...... The product easy to use no need of special operation and use. The internal circuit of the amplifier output in the form of the capacitor which can effectively avoid the internal circuit fault on expensive headsets harm to insert the headset sound source may generate impact sound (electrolytic output capacitors internal charge effect on the headphones and produced) the shock due to lower energy no adverse effects on the headset use find the following suggestions according to operation can effectively reduce the impact sound: firstly the amp volume knob to the minimum the sound and the amp connection first open the audio then open the amp 5-10 seconds after the earphone insertion sound is played according to adjust the volume knob to the appropriate place to...... Power supply (adapter): DC 5V 600mA Frequency response: 10-100KHz SNR: 98dB Crosstalk attenuation: 60dB Gain: 12dB (high) 6dB (low) The total harmonic distortion (10mW): The maximum output power: High voltage = 300mW (16) 200mW (32) 35mW (300) Low voltage = 120mW (16) 88mW (32) 13mW (300) Battery charging time: 300 minutes (PC USB) Cell broadcast time: more than 10 hours. Input impedance: >5K. Product size: 8.2cm (L) X5cm (W) X2cm (high) Product net weight: 105g