In a studio that became the home ground for jazz singer Yun hee-jung for 30 years, concert posters, newspaper clippings, microphones, a keyboard and other musical instruments show the history of the 70-year-old vocalist. Clad in leather pants and an eye-catching knitted hat, Yun brewed her coffee — the latest obsession for Yun, who lacks no energy. After expounding on her newfound passion for a while, she retur.