george4471 ...I did reverse the turntable leads and encountered the same problem. Approximately 5-10 db less on left channel.
That means the problem is either in your phono stage, preamp or amplifier, because you wrote this when you started:
... the left channel plays about 5-10 db lower than right channel ...
...yet the bad channel didn’t follow your change.
The next step is to reverse the left and right phono preamplifier output leads at the input of your preamplifier. If the bad channel switches to the right - which is likely given that your digital sources play ok - then you know the problem is with your phono preamplifier.