Chet Helms, a towering figure in the 1960s Bay Area music scene who brought Janis Joplin to San Francisco and ran the Avalon Ballroom during the Summer of Love, died early Saturday after suffering a stroke last week. He was 62. "Chet Helms was like one of the founding fathers of music scene here," said Mickey Hart, drummer for the Grateful Dead and many other bands. "He was really the heart and soul of the music scene here in San Francisco. He was more than just a promoter. The Avalon really captured the spirit and the vibe of the era."