An object of the present invention is to provide a digital amplifier which is
capable of preventing a reproduction of an analogue audio signal from a loud speaker,
when an output sound volume from the loud speaker is set to zero and when inputting
of a digital audio signal or an input signal is stopped. In order to achieve the
object, in the digital amplifier of the present invention, a silent PWM signal
output section 7 outputs a PWM signal having a duty ratio of 50%, instead
of a PWM signal generated by the PWM signal generating section 6, in the
following cases: the factor detecting section 3 detects that the digital
audio signal is multiplied by the factor "0" in the gain regulation section 2,
the silent signal determining section 4 determines that the signal input
from the reproducing unit 13 is stopped, and the silent signal determining
section 4 determines that the digital audio signal is a signal at a silent level.
