By this point Jethro Tull had been awarded six RIAA gold records for sales of Stand Up (1969), Aqualung (1971), Thick as a Brick (1972), Living in the Past (1972), A Passion Play (1973), and Minstrel in the Gallery (1975). For the 1975 tour, David Palmer, who had long been the band's orchestra arranger, officially joined the band's stage show on keyboards and synthesisers. In February 1975 Jethro Tull sold out five nights at the 20,000-seat Los Angeles Forum, prompting Melody Maker to run the headline "Jethro – Now The World's Biggest Band?" After the tour, bassist Hammond quit the band to pursue painting. John Glascock, who earlier was playing with flamenco-rock band Carmen, a support band on the previous Jethro Tull tour, became the band's new bassist.
1976's Too Old to Rock 'n' Roll: Too Young to Die! was another concept album, this time about the life of an ageing rocker. Glascock made his first appearance on this album, contributing harmony and second vocals in addition to the bass lines. Palmer continued to arrange, and he recorded as a guest on two songs. For the 1976 tour, Jethro Tull became one of the first bands to use giant projection screens for the larger stadium shows. Although Too Old... did not sell as well as the other 1970s albums, the 1976 compilation M.U. - The Best of Jethro Tull, achieved Platinum Album in US and Gold record in UK. A television special was recorded showing the development of the album's concept in a live show with the band (fully dressed in the most rock-hard-tongue-in-cheek outfits), but the programme was never officially released.
Folk rock (1977–1979)
In the late 1970s, Jethro Tull released a trio of folk rock albums, Songs from the Wood (1977), Heavy Horses (1978), and Stormwatch (1979). Songs from the Wood (1977) was the first Tull album to receive generally positive reviews since the release of Living in the Past (1972).