Though he doesn't get nearly as much credit as Deep Purple's Ritchie Blackmore, Uli Jon Roth helped lay the groundwork for neo-classical metal with his lead guitar work for German hard rock icons the Scorpions during the '70s.    Roth's playing owed an obvious debt to Jimi Hendrix, but the elegance of his lead lines, the fluidity of his phrasing, and his use of alternate scales learned from classical training all helped push his oeuvre into another realm entirely. Upon leaving the Scorpions in 1978, Roth embarked on an erratic solo career that found him exploring his psychedelic and neo-classical influences to a degree that would have been impossible with his former band.