They eventually abandoned cover versions and started composing their own music, still with a strong Keith Emerson influence for keyboard sounds that is most evident in the prominent use of the Hammond organ.
At the height of their glory, the band was often called a clone of ELP by the specialized press, not only because of the similarity of their music and the sound of their keyboards, but also because of keyboardist Fritz's virtuosity and classical training.
They returned to the studio in 1974 to produce their second album, Illusions on a Double Dimple with the Cologne Opera House Orchestra, Kurt Edelhagen's brass section and Karl Drewo's saxophone for the "Mister Ten Percent" suite, as well as a chorus composed of Ulla Wiesmer, Brigitte Thomas, and Hanna Dölitzsch.
Musicians present on the album include, among others, Hans-Jürgen Fritz on keyboards, Brigitte Witt on choirs who would later take part in the New Triumvirat band, as well as Helmut's sister, Elke Köllen also on chorus.
Shortly after his death, the German group Birth Control recorded and published a song in tribute to the bassist, entitled "We All Thought We Knew You," on their album Increase produced in 1977.
Triumvirat replaced Köllen with British singer Barry Palmer and calling on their original bassist Werner Frangenberg to record their next album Old Loves Die Hard, released in 1976.
This was the main reason for the departure of drummer and lyricist Hans Bathelt, dissatisfied with the direction taken by Hans-Jürgen Fritz and pressure from the record company, which pushed the group towards a more commercial pop music sound.
Changes of personnel for this album comprised Barry Palmer's replacement on vocals by David Hanselmann, Werner Kopal taking bassist Dieter Petereit's place, and Curt Cress giving way to drummer Matthias Holtmann.
The band's last album Russian Roulette was released in 1980, with Toto members Steve Lukather on guitar and bass and drummer Jeff Porcaro (who had also played with Steely Dan) plus other studio musicians.
In 1989, Hans-Jürgen Fritz released the soundtrack album for the movie Es ist nicht leicht, ein Gott zu sein (known as Hard to Be a God in English), on the CBS Records label.
Then in 1990, he released his only solo album, again on Columbia Records in Europe, and Sony in America, in the Millennium collection, entitled Dreams of Amadeus with Ralf Hildenbeutel, in which the music is based on Mozart themes.
Note that all their albums, including their latest Russian Roulette have been reissued in 2002 with additional titles, previously only available in singles, special mention for Illusions on a Double Dimple which is adorned with a different cover.