An audio recording and playback device, of the present invention, capable of recording and playing back audio, comprises an audio input section for converting audio input during an audio recording operation into an electrical audio signal, a power feed section for carrying out power feeds to the audio input section by means of a balanced transmission line, an amplifier section for amplifying the audio signal, a boost section for generating a power feed voltage to be applied to the balanced transmission line and outputting to the power feed section, a output voltage changing section for carrying out control to vary the output voltage of the boost section, and a control section for controlling the power feed voltage of the power feed section by controlling the power feed section and the output voltage changing section.