SMSL SMSL MINI5 50W2 TDA7492 Digital Amplifier & Headphone with Power Adapter (Black) TDA7492 core chip with superior output short-circuit and over-temperature overload protection. 90 % Efficiency, very suitable for use in the workplace for a long time . Built-in headphone amplifier ,130mW/32,, can drive fever headphones well. Designed power adapter to guarantee stable performance Automatically turn off the speakers amp circuit when the headphone amplifier is on