[6dj8]

I feel it has mainly to do with the shift to Russian tubes around the late 80’s.

The classic power tubes are more flavorful and rich sounding.

Gone are all the 6550 classic power tubes that are unavailable in matched sets.

The 6dj8 and 6992 and variants of NOS that are still around, allow for a spectrum of great sound quality not available with the "one choice" Russian tubes now used in ARC’s current products.

I do not think many "tube" equipment freaks today "roll" tubes for a particular "flavor" anymore.

IMHO that is a big mistake.