It seems like the characteristics I mentioned in the OP -- headroom, noise floor, resolution, timbre, imaging -- are all affected by the AC power line's voltage and noise, in that undervoltage reduces the system's current availability and noise increases the system's distortion.
It's still unclear to me whether there are additional AC power line factors that are relevant. Are all AC power line problems reducible to problems with either under/over voltage or noise?
bc
It's still unclear to me whether there are additional AC power line factors that are relevant. Are all AC power line problems reducible to problems with either under/over voltage or noise?
bc