Systems and methods are provided for switching between power supply rail voltages for a differential driver device of a class G amplifier device. The amplifier device employs power MOSFETs to switch between supplying high supply voltages and low supply voltages to the power rails of the differential driver. The class G amplifier can be employed in driving an ADSL signal over a telephone line. A control device ramps the power supply rail voltage between low power supply states and high power supply states to mitigate noise and spikes that can be coupled to the output signal.