David Wannen grew up in Washington hooked on Gilbert & Sullivan musicals after seeing the 1983 “Pirates of Penzance” movie starring Kevin Kline. Today he is the managing director of the New York Gilbert & Sullivan Players, the company that this week marks 19 years of performances in Wolf Trap’s Filene Center. An important perk of Wannen’s job is performing with the company. On Saturday, the bass-baritone will play the title role in this season’s production of “The Mikado.”