off u201d at a very high rate such that the output signal averages out to the desired analog voltage the output passes through a low pass filter to eliminate the high frequency switching noise and is then applied to the loudspeaker or earphone fig3 is a flowchart of the steps of the present invention the first step 1 of the present method is receiving a digital signal the second step 2 in the present method is generating a pseudo random number the pseudo random number is generated every clock cycle of a variable clock whereby the frequency of the variable clock is varied in accordance with the average amplitude of the received digital signal the least power efficient state of the amplifier is with a very low amplitude input signal for which there is close to a 50 percent chance that the amplifier will be switched u201c on u201d or u201c off u201d at each possible switching time in this case the amplifier switches much more often than when the input is at the extremes of its range and it generates more switching noise moreover the switching noise which when heard sounds like a constant hissing sound so called u201c white u201d noise in the background is more perceptible when there is very little input signal for that reason the present invention incorporates an average amplitude detector for high average amplitudes the clock speed of the pseudo random number generator is decreased for greater efficiency in this case more white noise is generated in the audio range but because of the.