How to tell if lp is recorded with phase reversed?

Phase can't be screwed up, beyond reversal, during mastering. It is in the recording and mixing that different mic feeds can be reversed individually. Also, if more than one mic is used simultaneously on a given "take", they can conflict with each other, creating timing confusion and comb filtering of different frequencies between the mic pick up patterns. Subtler phase issues can arise within the pickup pattern of one mic due to impulse reponse anomalies although this is not usually discussed as a phase issue per se.

All this is to say that some recordings are phase coherent within themselves but are reversed from absolute phase, and some are confused within themselves which makes it difficult or impossible to determine and correct. In the case of the former, the difference is a sensation of "hollowness" , lack of dynamics and bass impact.

Thanks to all for sharing your knowledge with me. This seems a difficult parameter to pin down, which I thought might be the case. Trial and error (try it you might like it), scenario. Thanks again, Dan

I have tried fliping phase many times with different components (including the GCPH), and I always seem to prefer non- inverted.

I wonder if there is some sonic penalty to the switch flipping phase?
When I had the GCPH in the system I shoudl have played a disc that says it;s phaze in inverted, like SHelffield direct to disks I believe. This might make a good test if you have one of these LP's.

Now that I am running a bi amped system (with a GCC-100 as bass amp) I can remotely just invert the bass (below 60hz)
Sometimes I find it is fuller that way, but usually less distinct.
Sometimes bass is not there in a recording even with the bass at full, so inverted phase of just the bass gets it to pop out. - This is seldom though.

... the difference is a sensation of "hollowness" , lack of dynamics and bass impact.

That is what we hear/feel in our system too. A small handful of our (classical) LP's give that giant sucking feeling. Big impacts start by pulling air away from you instead of hitting you with the initial wavefront. Creepy. We have no phase reversal switch, but swapping speaker leads is easy enough. Makes it all better, until you forget to swap them back!

FYI, Silent Running Audio has an Absolute Phase chart that you can download which lists the recording labels that had a tendency towards recording in phase vs inverting. This is just a guideline but may be helpful.