I recently acquired a 65' Princeton BF (non-reverb) and the rectifier tube is an unlabeled, probably chinese, tube. It is the 5AR4/GZ34 rectifier. I checked out ebay and NOS 5AR4's are big bucks..Not sure if its worth going NOS so Im consider trying a current production tube but I have no idea what is good and what is crap. All I can do is read reviews online from other users and I get the feeling that the Sovtek stuff is garbage, JJ/Tesla can me hit or miss and then it even gets a bit more confusing.. Groove Tubes are just relabeled chinese made to GT spec? Is it even worth going crazy over replacing this tube? Does it make a huge difference in "tone"? I already have some NOS glass for the 12ax7's and the seller had matching NOS JAN-GE 6V6GT's installed as well. Opinions please????? Thanks in advance guys!