The BA7757BK contains a playback equalizer amplifier, an REC / PB switch, a line amplifier, an ALC circuit with built-in detector, a recording amplifier, an analog switch for input switching, and a logic control circuit for independent switching of REC / EE, PR / EE, line mute and input. The IC is easy to interface with control systems, and features low noise during mode switching and at power on / off. The line amplifier and recording amplifire are directly connected internally, allowing construction of a high-performance audio signal processing circuit for VCRs using a minimum number of external components.