An apparatus to provide power for operating at least one gradient coil of a magnetic resonance imaging system. According to some aspects, the apparatus comprises a plurality of power terminals configured to supply different voltages of a first polarity, and a linear amplifier configured to provide at least one output to power the at least one gradient coil to produce a magnetic field in accordance with a pulse sequence, the linear amplifier configured to be powered by one or more of the plurality of power terminals, wherein the one or more of the plurality of power terminals powering the linear amplifier is selected based, at least in part, on the at least one output.