Power conditioner or not?

Musicnoise,

The scary fact is that some audio equipment does indeed benefit. I blame it on "switched mode power supplies" in many common household items from battery chargers to computers - these can be noisy. In the past everything used to be powered with large isolation transformers but not today. I have one component that benefits and it is digital - I don't know if it was jitter or what was wrong but a power conditioner helped. I tested two conditioners and both had the same effect on only one component. Naturally I will change this component next as I suspect less than adequate power supply isolation to the electronics somewhere.

I think you are right in principle as the best designs with overbuilt good power supplies should not need power conditioning in most normal situations.

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.

After further listening and critical examination with very familiar material, the conditioner DID rob the audio band of low level information and detail...extended listening is always key!! OOOPs, my bad!

Musicnoise, You "need" to learn that virtually all manufacturers -at all levels-are inclined to say "you need nothing further with our products". Most humans are not their own best critics.