Frank Sol
Lunatic Member
Of the three 12ax7 Tubes: Is the middle one a buffer? The outer two Right and Left channels?
As long as it functions properly the rectifier tube has no real affect on the sound. Can't say for sure if the middle tube is a buffer. You could try an odd one there and a matched pair on the outside. Although as I said before that thin board has too much flex which discourages tube rolling.
:thmbsp:
See attached...