Riddle me this....

@invalid 

Well of course, if the pre inverts phase you need to reverse the polarity at the speakers.

Recordings are phase inverting about 50:50. The only thing that changes is that records that were out of phase now will be in phase and vice versa. That is why a switch to invert phase is highly desirable in a digital component.

roxy, In your first post, I think you are thinking of the situation where one channel is 180 degrees out of phase with the other channel, in a stereo system. Yes, that causes very obvious problems, and needs to be corrected so that the two speakers are "in phase" with each other. The OP is asking about the situation where you reverse phase on both channels at the same time. Many listeners think there is a "correct" choice and say they can hear important differences when the choice is incorrect. For many boring reasons related to how recordings are made and room acoustics and the nature of crossover networks, I do NOT think there is a correct choice, so long as the two speakers are in phase with each other, but I do think that with many monopolar speakers and depending upon the room, there may seem to be a correct choice to some listeners (not to me in my room with dipolar speakers and using a panel of listeners who were blinded as to speaker phase). To each his own, in other words, in my opinion.

The logical extension of my findings for my system is I don't care a fig whether the preamplifier or any other component in the chain reverses phase (in both channels of course).  And I would not agree to the OPs proposition that inverting phase in both channels causes the image of the performer to move fore or aft.

Look for a copy of The Wood Effect, a book written by R.C. Johnsen. The book is devoted to the subject of polarity inversion. 

Don’t keep us in suspense. What is the Wood Effect, and what does it say on this subject?

I just spent 5 minutes reading about the Wood Effect. This was on another audiophile website in an exchange that took place in 2008. Seemed like the guy who brought it up did not really understand it himself, something about changing phase by 180 degrees at the amplifier/speaker interface, both channels of course. Why would that be any different at all from reversing phase anywhere else in the chain? Then there was a discussion that basically devolved into one of those where believers in the Wood Effect inferred that those who could not hear it are somehow Philistines using inferior speakers. One guy claimed it makes a big difference with Sheffield D to D LPs because they are "phase coherent".  Spare me.