Mac Mini mid 2011 - Is there any way to keep the analog audio output out of power saving mode?

This machine (mid-2011 with macOS Big Sur retrofit) is used as a HTPC/media player in a somewhat interference-rich environment. As long as there is some kind of media playback active, even if it is video with a silent audio track, all is fine. However, a few seconds after no longer playing back anything, it appears the sound circuitry powers down leaving the output in a somewhat high-impedance state, leading to all kinds of noise being picked up by the analog wiring (ticking noises that appear to be from some SMPS in the system if not using an audio isolation transformer, hum injected into the same transformer if using one). Is there some hidden software option to simply keep the sound circuitry on line (actively outputting silence) at all times?