This half century-old Bolivian ensemble is the equivalent of a superlative, studied European Reformation Revivalist band. Except that they’ve spent more time with homemade instruments. And with their (South American griot) grandfathers and grandmothers. And with childhood bedtime stories of the Golden Man. And border wars, in living memory, with headhunters, ritual cannibals and slavers from the Amazon basin on the other side of the Andes.