Rolf Ellmer (born 3 December 1960), also known by the names Jam El Mar and Trancy Spacer, is a classically trained musician and composer (concert-guitarist) and has become one of Germany's most known house and trance producers.

Together with Markus Löffel (alias Mark Spoon), also from the German music scene, he has recorded under several monikers such as Jam & Spoon, Tokyo Ghetto Pussy and Storm. He was also a member of the group Dance 2 Trance, along with Dag Lerner (alias DJ Dag), which had success all over the world and is said to be among the pioneers of trance music.