I have never listened to any crack otl but I've been living with 6080 for years, tried all 6080 of all versions and countries and found that the best was 6h13c from old Soviet Union. They do not magic, they do not make colorations, they do sound fine and natural.
I've tried many 6SN7s and i was over suprised by the sound of these Russian tubbies. In short, they're like Cognac, strong, impressive, addictive, sweet in the low-mid while carry an airy top-end. Bass is full-bodied, strong and melodious.
the only thing that i've been worrying about is the speed. I've got a HM901, it is definitely a my superman on sound quality side. But I'm thinking of selling it after a month due to its speed issue. HM901 is laggy and a bit slow. Even when I play 16/44 or 24/96.
HM901S is 100% built with metal, which is very superb. If anyone here have tried, please tell me more about the problem above?