He completed his studies with a doctoral dissertation about Elisabeth Kuyper (1877–1953), which was later published in the book Zes vrouwelijke componisten.

His composition Novelette for violin and piano (1986) was selected for the ISCM World Music Days in 1990 in Oslo.

During the Carl-Maria-von-Weber-Wettbewerb für Streichquartettkompositionen in Dresden in 1991, Jeths received a distinction award for his string quartet Arcate (1990).

His work Novelette was chosen by listeners of the radio program concertzender as the second prize for a competition celebrating 80 years of the existence of BUMA in 1993.

[2] In 1996, Jeths received the third prize in the Internationaler Wiener Kompositionswettbewerb for his violin concerto Glenz (1993).