Sound output device using vacuum tube, audio apparatus and method for sound output thereof

摘要

A sound output device is provided. The sound output device includes a vacuum tube for amplifying an audio signal; a power supply that supplies power to the vacuum tube; a first switch circuit that selectively connects the power supply to the vacuum tube; and a controller that controls the first switch circuit according to whether the vacuum tube is in use. When the vacuum tube is not in use, it is bypassed by the audio signal.