Inverting and or non inverting amp?

Cytocycle:
Good eye and good advice. I have a tube based preamp (Rogue 99) and just found out that I should have flipped speaker polarity at the speaker ends. (doh!!) Have to be totally honest though, it doesn't sound MUCH different than before. I just wanted to know what amps do invert?

Thanks guys for all of the responses. I have a test disc from my car audio days and I can now hear the difference with a track specifically used to judge relative polarity and phasing in and out.