A switching power amplifier of class D has a switching stage for generating a block wave signal by alternately switching the block wave signal between supply voltages. A filter (24, 25) generates a power output signal (22) corresponding to an input signal to be amplified, which is coupled to a linear input (19) that is free of hysteresis. A control circuit (27, 28, 29) provides feedback between the output power signal and the linear input for controlling both the gain in the operational frequency range and also the alternately switching of the switching stage. Hence, the amplifier oscillates controlled via the same feedback loop that also controls the operational behavior of the amplifier, resulting in low output impedance and low distortion.