An electronic class-D amplifier with intrinsically low distortion employing modulation of the slopes of a triangular-wave carrier reference signal; the modulation being in proportion to the derivative of the input signal. The negation of the distortion is most successful if this derivative signal is shifted in phase and gain to compensate for the closed loop phase and gain of the amplifier. The amplifier includes a pulse width modulator which includes an oscillator (5) with at least one integrator and a first comparator (6), at least one servo-loop amplifier (3), an input signal processor (4) which processes and modifies the input amplifier signal. An output signal of the oscillator produces a carrier reference signal (13) which includes at least positive and negati derivative components, which are modulated by an output of the input signal processor (4) which is applied to a modulation input of the oscillator (5), whereby at least the symmetry of the carrier reference signal is modulated. An output (11) of the output switching stage is fed back via a negative feedback path (15) to an input of the servo-loop amplifier (3).