The system consists of a voltage regulator, a single low noise inverting preamplifier and a mid supply referenced output stage. The voltage regulator provides a clean DC voltage for the microphone and preamplifier, so that at end of battery life conditions when the output impedance of the battery is high, the system maintains stable operation. The preamplifier and output stage have been optimally compensated to minimize aliasing effects normally associated with class D operation. The two stages have been DC coupled to reduce the external components required, thereby minimizing the hybrid footprint.