After being founded by Tom Oberheim in 1970, Oberheim Electronics first acted as sales representative for ARP synths and manufacturer of high quality effect modules. In the early 1970s ARP customers called for a sequencer and Oberheims “DS-2” was the answer – one of the first ever digital sequencers. Soon, the need for a monophonic synth-voice, for playing along to the DS-2’s sequences, became apparent. So Tom Oberheim and Dave Rossum of Emu-Systems designed the “Synthesizer Expander Module”, the “Oberheim SEM”. A compact add-on synth, with no keyboard, that could be controlled via CV-gate from other devices. It got released in 1974, at a price of 700 US-Dollars. The SEM went on to become Oberheims basic sound-generating building block of their following legendary 2-, 4- and 8-voice poly synths. In 2009 Oberheim re-released an updated version of the SEM, enabling MIDI-control.