The development of real-time power supply feedback for an all-digital class D PWM amplifier enables the use of many different power conversion techniques allowing a greater number of alternatives to meet system demand requirements. With a typical voltage ripple rejection of 40dB at 60Hz, an all-digital PWM amplifier with this PSR compensation can achieve better than 105dB system dynamic range and a total harmonic distortion plus noise measurement of 0.1 percent. The system performance of the real-time PSR feedback is discussed and evaluated for a half-bridge and fullbridge amplifier output stage powered from a low cost unregulated linear power supply.