I'm looking to upgrade the 12AX7 tube on my Fender Super Champ XD as I hear the stock one shipped with it isn't very good. When I look into suppliers I see several different kinds: Sovtek 12AX7 EH Sovtek 12AX7 WA Sovtek 12AX7 WB Mesa Booge 12AX7/SPAX7A Groove Tubes 12AX7C Groove Tubes 12AX7R2 Groove Tubes 12AX7R3 I play with a EJ Strat. I like round smooth glassy/chimey tones when I am playing clean on the neck/middle PU as my major consideration. Secondary is cutting treble for highly distorted/overdriven sounds on the bridge PU. Can someone explain the diferences between the tubes and help recommend or narrow down the field? Cheers in advance!