A control system comprising a gain control circuit for adjusting the gain of an input signal to provide a gain controlled signal and an integrator for integrating the gain controlled signal to provide an output signal. A first circuit responds to a particular condition for changing the gain of the gain control circuit and a second circuit responds to that same condition for changing the output signal independently of the gain control signal to bring about a more rapid change in the output signal than could be brought about solely by changing the gain controlled signal.