once again, a sales technique - if it is perceived as exclusive, then it must be desirable. Why else would "STR" tubes from China be regarded as anything other than Chinese tubes?
Again, the STR designation in modern times with regard to current production tubes has absolutely no real meaning! The Eastern European and Chinese Manufacturers don't produce special Tube Requests.
Get past the "gurus" who just want to talk you into purchasing something "special." The emperor has no clothes.
For your Boogie, with no adjustable bias, with current production tubes, purchase matched sets. Without regard to brand. I've gotten the best mileage, with respect to 6L6 types, in this order: Winged C, Shugwang, Sovtek 6L6WXT+, JJ. The worst performance regarding power tubes was Ei.
Let the flames begin...
ty