Robert53, Three things come to mind.
First, in published measurements made on high-powered amplifiers, some testing lab mains sag and do not provide sufficiently high voltage and power to supply the amplifier with 120 VAC. Krell tests comes to mind. The test reports usually forgive the amplifier for not meeting specified output in these cases. From that I gather that brownouts/sags will compromise power amplifier performance.
Second, these days, in the northeast, mid Atlantic, and surely other parts of the US, the high temperatures lead to high demand for electricity, and mains power quality suffers. Being a close lietener and a "fixed income person", I fear erratic power fluctuations, which will compromise system performance and could possibly do severe damage an amplifier.
To navigate those concerns, I listen until about noon most days, and then shut down until after dark. This is in contrast to my preferred MO, which is to rotate an amplifier into my system and leave it powered-up for one or two months.
A few years ago, I tried a Monster power regulator of some kind. Specs of that regulator were above the power my Mc7270 would draw. After using the regulator for about a month (and playing at about 70dB through reasonably efficient speakers), around 5:30 on a weekday, a power cap failed and an energetic fire started in my living room. Sure, the caps were old, but I'm left to wonder whether that regulator played a role in what happened.
