Power conditioner or not?

Power conditioning is what you have a power supply for in you amp, receivere, preamp, etc. Unless you have poorly designed equipment (and that is highly unlikely if it retails for more than $100) or live above a machine shop with large lathes operating on your same power feed, you do not need a power conditioner. A surge protector is a wise idea. If you are worried about power dropping out completely buy UPS and a generator. I spent 20 years working as an engineer with medical equipment in critical care areas and research labs - from microvolt level signal acuisition to kv x-ray equipment to life support equiptment - no one used power conditioners.

Physics and science are not changed by the application. Audio is not rocket science.

As to the individual who initially asked the question. You may want to consider contacting a design engineer at the manufacturer(s) of your equipment or the equipment that you are thinking about purchasing and posing your question to that individual. (Assuming of course that the manufacturer does not also sell power conditioners and thus is free of a bias based on pecuniary interests) Absent that, stop in at your local university and chat with a professor of electrical engineering. If you contact more than one of those sources, you will likely find uniform answers.