Charles B. (Hoppy) Hopkins, studio sound engineer, died Jan. 18 at St. Joseph’s Hospital in Burbank after an illness.He was 92. Hopkins was a member of the early sound crew at Paramount when the studio switched to sound in the late 1920s. He then went to work for Warner Bros., where he was credited with designing and building the prototype of the Moviola used during World War II. Hopkins is survived by his wife of 53 years, Dorothy; son, Charles (who works for Paramount Pictures); a daughter, Joyce Hopkins; and four granddaughters. Services will be held at 11 a.m. today at Forest Lawn, Hollywood Hills. In lieu of flowers the family requests donations to the Motion Picture Home.