SMSL sApVI Big Power High Fidelity Stereo Headphone Amplifier + DC24V Power Adapter - Black sAp VI is special designed for computer ,DVD, HD Player and MP3 etc, which can not develop headphone amp function due to their small output power. SAp VI power adapter has passed the safety test. High voltage AC3750V/5ma/60S test. SAp VI shell using the aluminum material, CNC high precision machining, drawing oxidation treatment