Are manufacturer AC cables good enough?

If a power cable changes the sound of the amp perhaps your "Ayre Conditioner power line RFI filter" is faulty.

I see. So the conditioner has the magical property of making anything plugged into it sound the same. Power cords no longer matter. Interesting. Tell me more. So I could use lamp cord, or extension cord, it can't change the sound, it would sound just as good no matter what? There is nothing anyone can do after the conditioner that can affect the sound in any way. Not unless the conditioner is faulty. Is that right?

Are you sure you have thought this one through? 

Ha ha ha!  The "religion of IEC cables" !!! You have the power cables that run in the walls from your power center to the AC outlet near your soundsystem:  They are just plain straight parallel copper cables @ cents per feet...

And you would get "a much better sound" placing those "magic IEC cables" between the AC Outlet and the equipment?   We call that the placebo effect and it will cost you a premium!!!

Not only that, equipment must be certified for EMI and the power supplies / casing must be designed for that.  And it's not like power supplies are new technology...  If your equipments are so "fragile" not to support a normal environment, it is simply by mean of a bad power supply design.  In that case, change that badly designed equipment for something better, whatever the price you paid...

@itsjustme Exactly!!!

My $2600 phono amp improved by a notable amount by replacing the power cord with a $39 OFC cable with rhodium-plated plugs. The manufacturer should supply a better cable than the standard dollar cable.