An electrical amplifier comprising an output stage that can be supplied by an electrical energy source, is connected to a control device on the input side, the control signal of the control device controlling an output signal of the output stage dependent on a parameter value of the energy source. The amplifier is has a compensation device that is connected to the energy source and the control device, and is used to modify the control signal according to the parameter value of the energy source which can be, for example, the network voltage of the energy source. A method for controlling an electrical amplifier comprising an output stage supplied by an electrical energy source includes, determining parameter value of the energy source, deriving a compensation signal therefrom, and a control signal for the output stage is generated according to the compensation signal. The amplifier and method can be used in a gradient amplifier for a magnetic resonance appliance.