Abstract: A direct-drive digital audio amplifier for electrostatic loudspeakers (ESL) includes a pulse-width-modulation (PWM) generator that generates a PWM signal from a digital audio signal received from an audio source. The generated PWM signal is amplified to a high voltage, such as several hundred volts, by a high-voltage switching circuit. The amplified PWM signal is then applied to the stator panels of the electrostatic loudspeaker (ESL), whereupon the amplified PWM signal is low-pass filtered by the electrostatic loudspeaker to generate audible sound waves, which are then high-pass filtered by a listener's ears, so as to audibly reproduce the digital audio signal.