An audio system's power amplifier should be turned on _____.

Turning on an audio system's power amplifier after checking the audio signal level at every gain stage of the system is critical for ensuring optimal performance and preventing potential damage. This practice helps to confirm that the signal levels are appropriate and that there is no risk of overdriving signals, which can lead to distortion or clipping.

By checking the signal levels first, you can ensure that the audio source isn't too high or too low, which maintains audio integrity and helps avoid any possible equipment damage. Ensuring each gain stage is set properly before activating the power amplifier allows for safe operation of the entire audio chain, ensuring that interactions between components are as desired without unexpected peaks that could cause issues.

This careful approach aligns with best practices in audio system management, emphasizing the importance of proactive checks before engaging amplification.