Impact of phase inversion by preamp

I have a phase switch on my preamp. It usually has minimal effect. Apparently, you should switch back and forth and use whichever setting results in the best bass. Good first post!

The importance of maintaining "absolute phase" aka "polarity" in a system is controversial. One reason for that is that many recordings have been engineered with a large multitude of microphones, and have been subjected to extensive electronic post-processing, the result being that different instruments and different vocalists may have different polarities on the same recording.

Whatever difference it might make is most likely to occur on recordings that have been made with a minimal number of microphones (ideally just two or three), and that have been engineered with minimal post-processing. Some relatively small producers of classical recordings tend to be in that category.

Also, in the case of preamps which provide a polarity switch it should be kept in mind that when the position of the switch is changed, in addition to the polarity of the signal being inverted the internal circuit configuration of the preamp is being changed. Which depending on the specific design might in itself have minor but audible sonic consequences, especially in the case of preamps that are not "fully balanced," i.e., that have single-ended internal signal paths.

Regards,
-- Al

I concur with dweller, the impact is subtle, but noticeable.
You should really try using it.
BTW, there are some recordings with the phase inverted, so if you notice something 'off', just toggle the switch and see if it helps.
Bob