Something strange with imaging

Dear @olp88 :  I told you that leave that way, it's spot on with reversed cables. Whay bother about, reversed cables does not makes any harm to what you are listening.

Now, what could be reversed could be the tonearm internal wires but again why bother about when you are listening fine with the reversed cables.

Is up to you.

R.

Yup could easily be the ears and solution maybe a pro ear cleaning.  Eliminate that possibility first.  I recently had a similar problem.   Sound was  suddenly unbalanced and highs distorted.  At first I thought my hifi was maybe snuffing it but a few simple tests established it was mostly my right ear.   Got the past due ear cleaning and voila, heaven once more. 

Dear @wlutke and @mapman and any other aspiring ENTs,

Not ear wax.  That was the first thing I checked!  All other sources including CD, streaming, and reel to reel have perfectly centered imaging through the same preamps. Any other ideas?

Hard to say. I had a similar sounding case recently where I found a particular phono preamp setup I was using to convert to digital had a small hardly audible but measurable difference in output levels left to right. It was simply a minor flaw that may have developed with the device over time. I went to a different setup recently but with same cart and step up transformer, and now things measure equal left and right as they should.

So ideally it’s just a poor connection or combo of connections perhaps but always possible any device involved in signal path from the cartridge on could just be off somewhat left versus right. I’ve seen it happen on multiple occasions over the years with phono cartridges in particular.

It’s also possible more than one device in the chain has some l-r output level difference and they cancel each other one way and augment each other to be heard the other.

Not a good idea to judge channel balance with a stereo recording, because you don’t know what the recording engineer had in mind. Better to use a mono LP and listen for a centered image.

your seemingly conflicting results could reflect differences in stereo recordings.