NEW YORK — Jack Moelmann is a retired Air Force colonel with a passion for playing the pipe organ. His love for the instrument runs so deep that he recently plunked down nearly $120,000 to fulfill a lifelong dream — to perform on the famed Wurlitzer organ at Radio City Music Hall .

On Saturday, the 67-year-old Moelmann will sit at the ebony horseshoe-shaped keyboard console at the magnificent Art Deco concert ...