on the heels of its belated hit single, styx signed with a&m records and released "equinox" (1975), which sold well and yielded a minor hit in "lorelei", which reached no. 27 in the u.s. more importantly, it contained the rock anthem "suite madame blue", which gained the band considerable recognition and airplay on fm radio in the relatively new album oriented rock (aor) format. following the move to a&m, guitarist john curulewski suddenly left the band as they were to embark on a nationwide tour in december 1975, due to his desire to spend time with his family. after a frantic last-minute search, the band brought in guitarist tommy shaw as curulewski's replacement.