Preamp inverts signal.

Good responses above.  A point I would add is that when the setting of the switch is changed you are not only changing the polarity with which the recording is reproduced, you are also changing the circuit configuration of the component in which the switch is located.  In some cases you might even be inserting or removing an active stage from the signal path. 

So you may find that one setting is usually preferable to the other one simply because the component sounds better that way.  At least, that is, if the inversion is performed in the analog domain rather than the digital domain, which is usually the case in preamps but perhaps not in your CDP.

Regards,
-- Al
 

Geoffkait 03-20-2016 7:17am EDT
Of your system is in the correct absolute polarity the Out of Phase track will sound like it is coming at you from all around the room with no specific direction. And conversely the in phase track will sound like it’s coming from dead center and be very focused.

The description of "out of phase" in the first sentence is the effect of relative polarity being wrong, not absolute polarity being wrong. In other words, it is the effect of having the output of one speaker out of phase with respect to the output of the other speaker. Which would be the result of having + and - reversed in the connections to one speaker (but not both). The effects of incorrect absolute polarity (having the outputs of both speakers inverted, relative to the polarity that is presumed to have been received by the microphones during the recording session) are vastly more subtle, and may be imperceptible on most of the recordings that have a mix of different polarities for different instruments and singers.

Phd, thanks for the nice words.

Regards,
-- Al