STK4172-2 power amplifier IC gives you a very low-noise ratio THD stereo 2x40w = 0.4% max supply voltage symmetrical 2x48v dc recommended value 8 ohm speaker with amplifier is feeding on a solid addition to the same pcb with... Electronics Projects, STK4172 Amplifier Circuit 2X40W "audio amplifier circuits, ic amplifier, " Date 2019/08/03