preamp inverts polarity

Please Kaitty, don't tell the various venues who keep hiring me for my live sound mixing/production skills...I wish I had a closet full of dusty magic rocks and various snake oil sonic remedies so I could enjoy being a failed imaginary "Industry Insider." THEN I'd get some respect!

I imagine it’s because you work cheap.

I'd suggest throwing out the cables that are specifically designed to color the sound. We're talking AC signals here. Both conductors see positive and negative. Anything that doesn't conduct both equally is failing. 

Well, relative to Kaitty at least I work in the live sound business, where in his case he seems to work only for the cheap shot. 

I have a tube preamp that inverts polarity (for some reason it is designed that way).  I reversed the speaker connection on one of the speakers, and it sounded better to me.

Playing a test record confirmed my suspicion.

The catch is:  not all of my records sound better with the speaker wires reversed on one speaker.  I would say 80% of my records sound fine either way (I can't hear a difference), but some (those with good sound staging) have improved "imaging" (if I am using that term correctly).  And a few "image" better the other way.

This makes no sense to me.  Is "phase inversion" the same as "polarity inversion"?  And why do some recordings seem to have it backwards?

And why would anyone want to change both speakers?