Yes, the purpose of an audio component's power supply is to turn trashy power line power into good-sounding tunes. Seriously. In modern times its not unusual for a component's power supply to take a fairly clean waveform from the power line, turn it into utterly trashy square waves or worse, and then turn it into great sounding tunes.
Amir's advice about not putting the power amp on the UPS is good. It is akin to the IT guy who tells you to not put your laser printer on your UPS. However, most power amps and AVRs don't draw excessive power unless you crank them up.
As a rule audio gear can handle brownouts pretty well, and without damage. The UPS is primarily a tool to handle short term outages.
I just lived through a couple of years of horrific summers that were filled with uncountable outages and brown outs. It was all due to a pizzeria moving onto my block. The ovens were the straw that broke the power system's back. In the end a complete re-engineering of the block's power system at an alleged cost of close to a million dollars including all new poles and wiring and the addition of two additional pole transformers. This did the job.
It turned out that the failures seen at my house were primarily on just one phase of the two that feed my house which is typical. While the audio gear was on the failing phase the outages were lengthy enough that no UPS would have helped me. Moving the equipment o the other phase with an extension cord was all it took to obtain a major improvement.
If you are worried about power surges, you want a whole-house surge protector.Edited by arnyk - 11/15/13 at 5:29am