Order a new set of 6H30P's directly from a Russian vendor. Same for a 6550. No need for any special "selection" as ARC claims!
Replacement Tubes for ARC Reference 6
I realize that the tube replacement for ARC's Ref 6 are good quality, and when I get these from ARC they would be matched. I believe these are all Russian--good, but not great. Is there any reason to check for better quality tubes when I do a replacement? These are 6H30P and 6550WE tubes.