A shaker test system with a class D power amplifier having an analog to digital converter to receive an analog input signal and convert the analog input signal to a digital signal, pulse width modulation logic coupled to the analog to digital converter to provide a delay time to a delay line to control a transition time of a pulse width modulated signal responsive to an output of the analog to digital converter, and a class D power output stage coupled to the delay line and responsive to the pulse width modulated signal to provide an output of the class D power amplifier stage. The class D amplifier allows use of a low cost microcontroller to obtain very small pulse width increments using a low cost microcontroller to provide a low cost shaker test system incorporating the class D power amplifier.