An audio amplifier is disclosed. The audio amplifier for driving an electroacoustic transducer includes an H bridge circuit including a 1D-class amplifier connected to a (+) electrode terminal and a 2D-class amplifier connected to a (−) electrode terminal of the electroacoustic transducer; a pulse width modulator configured to receive an audio signal, generate a first and second pulse signal for each driving the 1D-class and the 2D-class amplifier, and adjust a phase difference between the first and the second pulse signal; a first driver driving the 1D-class amplifier depending on the first pulse signal; a second driver driving the 2D-class amplifier depending on the second pulse signal; a level detector detecting a level of the audio signal; a phase adjuster configured to set a phase difference between the first pulse signal and the second pulse signal of the pulse width modulator based on a detection result from the level detector.
