Turntable channel imbalance

You wrote, "In this instance I referenced the digital copy in comparison."  Do you mean to say that you listened to the CD or streamed version of the same music, and it does not seem out of channel balance?  If so, that is not conclusive evidence you have a real problem in your vinyl system, because creating the digital version involved the imposition of more engineering at the other end.  Try the mono LP experiment anyway.

It is unwise and often very misleading to judge channel balance while listening to stereo LPs. You have no idea what the recording engineer had in mind when he calibrated the recording equipment. Furthermore, the room itself often plays acoustical tricks that make one channel appear to be louder than the other. The easiest thing to do in a home environment is to play a mono LP on your stereo system and listen for the location of the image. If the image is right between the speakers, you probably have no problem.