Power conditioner and high end power cord

How can a power conditioner make a system sound SIGNIFICANTLY better?  I would like to hear the difference.  If you never heard a system through a power conditioner no one would ever notice.  Upgrade your speakers or CD player.

I would imagine it depends on the incoming power in your area and the power supplies of your equipment.  The power supply in my TRL DUDE is about as heavy duty as any amp, yet the sound improved very noticeably when I added a Core Power Tech Equi=Core150 PC and ran it directly to the Maestro wall outlet.  This is even though I was using at least a mid level power cord prior.  Surprised me how much difference it made on that one.  I have 3 dedicated 20 amp runs to the circuit box but it's not a separate panel from the rest of the house FYI.

I don't believe anyone would hear  "SIGNIFICANTLY" better sound reproduced from any "one" tweak in their audio system.  I do, however, receive more information through my speakers having added the TORUS RM-20 power conditioner, (two years ago) whether the source is from my TT or CD transport.  Simply more information.  One thing that should be determined in a forum such as this one is:  Does a tweak give you "better" sound or just "different" sound. A difference in the information you hear can be quantified, but is that difference actually "better" ?  I just added an Audioquest NRG-Z3 power cord from the TORUS to my amplifier.  This was added as a request from a retail audio boutique owner I've know for many years.  I use good quality cable for interconnects and I terminate these cables myself so I'm not one to purchase expensive cabling. HOWEVER... this Audioquest AC cable created a very discernable change in what I was hearing through my speakers and I'm still (after a week) not sure if the change is better than I was hearing before, but it's certainly different and I don't know why.  To be truthful, I didn't want to hear a difference.  I wanted to return this cable and get the refund promised if I wasn't convinced that it improved the sound. Now it's a conundrum ..

I thank you all for your input it was helpful and looks like I need to do some comparison. 
Someone  asked who I bought the core-1800 from it was a small company in Colorado I think his name was Mark. I bought it brand new it took a month plus to get it seems like a small family operations they where very good people to deal with because it to longer to make and ship they took $500 off the unit and I paid $1,200. 

@OP,
You are venturing into shark infested waters. 
Mark sold the company recently and many buyers (including myself) are owed merchandise.
I own 2 Equi-core 1800's and they work as they should, thankfully.

B