In March 1975, Teach-In participated in the 1975 Eurovision Song Contest with the song "Ding-a-dong" (written by Will Luikinga and Eddy Ouwens) and won. Teach-In broke an Eurovision convention that favours songs performing later in the program by winning the contest despite performing first. This was a first for the competition and was repeated a year later by Brotherhood of Man in the 1976 Eurovision Contest. This feat has only been repeated by one further act; the Herreys in 1984. "Ding-a-Dong" had a chart entry in nearly every European country, as well as a number 22 placing in the USA on the Easy Listening chart. In the Netherlands it reached number 3 in the charts. In October 1975 "Goodbye Love" became another Dutch top 10-hit. "Rose Valley", released in February 1976, reached just the top 20. Tensions due to the busy concert scheme made Getty Kaspers leave the band, after which she pursuited a solo career. Also John Gaasbeek and Ard Weenink quit. Hans Nijland (bass, in 1977 replaced by Nick De Vos), Betty Vermeulen (vocals), Marianne Wolsink (vocals, ex-Head) were included as new members. The group's next single "Upside Down" reached number 2 in the Netherlands.