About The Aiyama A04 Hi-FI Amp: Power your passive speakers up to 175W power each channel ^^ Advanced circuitry design with mcu intelligent monitoring and circuit protection Aluminum chassis and all metal heavy duty design ^^ The NE5532 op amp can be upgraded to a dual op amp like OPA2604 High quality components and plug-in capacitors for best frequency response, ELNA audio coupling ^^ Using a TI hi-def digital power amp IC (TCA3251, ) you get the best quality clear sound from your speakers