I'm watching this thread closely as well. I'm not trying to sidetrack either, but wouldn't it be ideal to run a tube rectified solid state Phone stage? Or just go SS phono like the Pearl 2 into a tube PRE. Just playing a bit of devils advocate here.
I personally have had a lot of issues running down microphonic problems with tubes. Cost me hours of troubleshooting to find out it's the new gold lions I purchased. Vinyl is hard enough to get right.
We like tubes for the H2 harmonics. On occasion our systems with these harmonics run them at the negative and positive phase depending on our setup.
My point is to explore and see if you like +/- phase H2 harmonics or more 3rd order in your gear. It will help eliminate a lot of guess work. Have you tried another full tube phono stage or added tubes anywhere else in the system? It can change your negative phase to positive phase harmonics.
I'm not trying to open some crazy can of worms either....
I run a Klyne Audio Arts phono/pre btw.
Nate