An audio amplifier comprising an input block, a plurality of switches, an output filter, a current monitor and a proxy signal generator is provided. The input block is configured to receive an input signal and to provide a modulated signal. The plurality of switches is configured to generate an audio unfiltered signal including an undesired switching frequency component in response to the modulated signal. The output filter includes a coil and is configured to filter the undesired switching frequency from the audio unfiltered signal. The current monitor is configured to transmit a measurement output including a first operating frequency. The proxy signal generator is configured to provide a proxy signal including a second operating frequency. The input block is further configured to receive the first operating frequency and the second operating frequency to operate in accordance to the first operating frequency and the second operating frequency.