Instruction:1，Do not use cheap audio signal cables， these cables are without shieldiing， they will lead in high frequency noises.2，The bigger the rotation， the larger the noises3，The correct using sequence is first connect laptop power with amp power supply port， then charge the laptop.Specification:- Adopting top for red ring output inductance， no output consumption， more pure sound voice- Full allumnium alloy body， gold plated RCA and crystal loudspeaker line column， more gorgeous- Adopts Germany MKP10 as output， more rich overtone- Adopts high speed capacitor array. lower internal resistor， dynamic more violent- Gold plated RCA port output， Taiwan imported sealed potentiometer， thicken allumnium alloy radiatingPower Voltage:12V ------- 8ohm loudspeaker/12W(left channel) +20W(left channel ) + 12W(right channel) 4ohm loudspeaker /20 (left channel)15V ------- 8 ohm/18 + 18W，4ohm/ larger than 30 + 30W19V ------- 8 ohm/32 + 32W，4 ohm/ larger than 45 + 45W24V ------- 8 ohm/38 + 38W，4 ohm/ larger than55 + 55WPackaged Includes:1x Digital Amplifier (NO POWER SUPPLIER )