Sin After Sin is the third album by the British heavy metal group Judas Priest, released in 1977. It was the band's first album on Columbia Records after their contract with Gull Records was terminated, as a consequence of which they lost all rights to Rocka Rolla and Sad Wings of Destiny, and any other demo recordings made during the production of the two albums. This album featured the drum work of a young and upcoming session drummer, Simon Phillips, who was only 19 at the time of recording. The record features a cover of Joan Baez's "Diamonds & Rust", a track that would become a live favourite from then onwards. The album was remastered in 2001, with two bonus tracks added. One of the bonus tracks "Race With The Devil" was at first intended to take the place of "Diamonds & Rust" but their producer, Roger Glover (of Deep Purple fame), wanted them to switch to "Diamonds & Rust", saying that "It would fit along with the rest of the album better."
Essential: a masterpiece of progressive rock music.
When speaking of Progressive music, in general I prefer studio albums to lives because the studio work allows the artists to put as many details as they want in their music.
This album is the exception. It's first of all a rock album. The quality of the sound is "Fit for purpose" in the sense that you know clearly that it's live music and this is the kind of sound that a rock live must have.