Congrats on your new VHX!
I've seen a lot with VHX Power tubes.
First VHX I received had KT77s, sounded amazing, but the Pre-Loop didn't work, so I returned it.
Second VHX came from Fed Ex with a hole punched in the side, scratching the faceplate, so I returned it.
Third VHX came with 6L6STR Tubes, and I tried to like them, but I returned it.
Fourth VHX came with KT77s, and I love my VHX!!!
You can actually put any tubes you like in the VHX: 6L6, EL34, KT77,
as long as you bias for the particular tubes.
Factory bias for my KT77s was an average of 35.2 mA (35.2, 33.2, 35.2, 38.7)
I can't figure out what that signature says either, but I love it!