The STK401-060 is a thick-film audio power amplifier IC belonging to a series in which all devices are pin compatible. This allows a single PCB design to be used to construct amplifiers of various output capacity simply by changing hybrid ICs. Also, this series is part of a new, larger series that comprises mutually similar devices with the same pin compatibility. This makes possible the development of a 2-channel amplifier from a 3-channel amplifier using the same PCB. In addition, this new series features 6/3 drive in order to support the low impedance of modern speakers.