A sigma-delta modulated amplifier is disclosed that is operable to sum an input signal and a feedback signal, integrate the summed signal, asynchronously quantize the integrated signal, sample the quantized signal utilizing a pseudo-random osculating signal, and amplify the sampled signal. The amplifier enables discrete implementation of a low-cost, spread spectrum controlled, sigma delta modulated audio amplifier for spectrally pure, high efficiency, low EMI, audio power amplification.