Technical question on phase inversion.

 Your pre amp inverts phase. Many tubed pre's do. Many recordings are not actually " in phase" , tho' I think that the majority are. I would just swap your speaker connections as per your manufacturers instructions be content knowing that  youll be " phase correct " the majority of the time.

If using a sub on the same wall as your mains invert it's phase too

Roughly speaking, 50% of all recordings are 'phase inverted'. If the recording is multi-miked and multi-tracked, its going to be really hard if not impossible to hear the difference.

The audible significance of inversion or non-inversion of polarity, aka "absolute phase," is controversial. In part because many recordings are comprised of a random mix of polarities for different instruments and/or singers. Consistent with Atmasphere’s comment, it is most likely to be significant on the relatively few recordings that were engineered using "purist" techniques, meaning just two or three microphones and minimal post-processing.

Interchanging + and - on both speakers (or on the corresponding output terminals of the amplifier) will of course compensate for the polarity inversion your preamp imposes on both your CD and vinyl sources. However if the CD player is also known to invert polarity (which would probably be mentioned in the measurements section of Stereophile’s review of the player, if they have reviewed it), and your phono stage does not, then you would not want to interchange + and - on the speakers. Instead you could make everything come out correctly by interchanging the cartridge connections for each channel (i.e., interchanging white with blue, and interchanging red with green).

Regards,
-- Al

Thanks for your responses, so far. I gather that "absolute phase" is not really absolute, as it can change with the recording and even the source component can play a part. I doubt that my Oppo 105D contributes to the polarity inversion, but who knows (LOL). In any case, it just feels strange to reverse the cables on the speakers. Based on your comments, and the manufacturer's suggestion, I'll leave them reversed. Thanks for your explanations and suggestions.