Clarence Carter, the blind Alabama soul singer and producer who made a string of hits in the '60s and '70s, has passed away. Rolling Stone reports that Carter passed away today after a stage 4 prostate cancer diagnosis. Carter was 90. Clarence Carter, born blind, grew up in Montgomery, Alabama and graduated Alabama State University in 1960. As a young man, Carter was one half of a duo with his friend Calvin Scott; they recorded early-'60s singles under the names Clarence & Calvin and the C&C Boys. After Scott was hurt in a car accident, Carter kept working as a solo artist, and his 1967 single " Tell Daddy " reached the R&B charts and inspired an Etta James answer record. From there, Carter signed with Atlantic, and his 1968 breakup song "Slip Away" became a crossover top-10 pop hit. More hits followed.…