out of phase

does any one know if a B&K sonata pro 10 preamp inverts phase. also is there a good cd out there to test for proper phasing
Stereophile has produced several test CD's, both of which contain phase tests.
Inverted phase is not the same as out of phase. Out of phase would imply that the left and right channels have different phases. In the world of recorded music there is very little that is correct phase.