This amplifier uses a Texas Instruments TPA3122D2 IC and circuit board from Jerry's Electronics in Springfield, Ohio. I installed a LED volt meter, which gives an accurate reading of the power supply voltage. The IC can operate safely within a range of 8 and 30 volts DC. I use a 12 volt SLA battery or two 12 volt batteries in series for 24 volts. Power output rises as the power supply voltage is increased. From 8 to 15 watts. The pcb board is mounted on a one inch thick slab of American soft maple.