In this I Puritani, a singer’s opera, all sing at their best and seem to have endless fun doing it. Beverly Sills, a shameless show-off, effortlessly shoots out sparks. The young Pavarotti is ardent and full of easy high notes. Louis Quilico and Paul Plishka are not to be outdone, and their “Suoni la tromba” is the rouser it should be. Nobody forgets melody and line, aided by Anton Guadagno, the perfect conductor for this music.