SMSL sApII Pro TPA6120A2 Big Power High Fidelity Stereo Headphone Amplifier (silver) 2 way switch input circuit (3.5 earphone seat and the RCA block),Replacement of the input signal is no longer need to pull line, just select the switch panel. high precision power divider circuit. Guarantee the stability of the circuit and reduce the DC drift output. high input and output connection seat to ensure the signal channel is smooth and durable. audio channel all use the United States Army Regulation DALE have a fever resistance Low noise, sound quality is good. Disadvantage: price is 20-100 times that of ordinary resistance Japan PSE certified power distribution Corrugated low, radiation small, durable. 6.35mm earphone output jack Additional 6.35 to 3.5 conversion base, apply to the use of HI FI headphones