the invention provides an amplifier for providing adaptive operation of an auditory prosthesis . the amplifier receives an input signal and produces an output signal , and comprises a gain control . estimates of the current noise floor value of the input signal are obtained , and in response to a change in the current estimated noise floor value , the gain control alters the amount of gain applied to the input signal . further , in response to the change in the current estimated noise floor value , the gain control alters a gain compression ratio of the amplifier across the dynamic range of the amplifier . the present invention allows for adaptive operation of the amplifier responsive to varying noise floor levels , while maintaining desired gain characteristics of the amplifier across a range of input signal levels .