A pulse-width modulation (PWM) amplifier comprises a feedback loop for reshaping the pulses of the PWM input signal to correct timing and amplitude errors in the class D output stage of the amplifier by means of an error correction signal. In such an amplifier the feedback loop gives a substantial amount of base-band noise when the pulse-period of the PWM input signal is not constant, which is especially the case when the PWM signal originates from a noise shaper. The invention reduces this noise by modifying the reshaping gain of the amplifier with a pulse-period proportional signal.