Off hand, I don't know of any source components with inverted phase, although I suppose it is possible that some tube DACs or CD players do invert. If such is the case it should be plainly stated in the manual. When in doubt, contact the manufacturer. Also, many DACs and some preamps have an inverting switch where one push of the button is all that's required (rather than changing speaker leads) which is a useful feature.
I might add that in the case of an inverting source component connected to an inverting preamp, the two negatives do make a positive, i.e., once the signal leaves the preamp it will no longer be inverted.
I might add that in the case of an inverting source component connected to an inverting preamp, the two negatives do make a positive, i.e., once the signal leaves the preamp it will no longer be inverted.