The VCS 3 (or VCS3; an initialism for Voltage Controlled Studio, version #3) is a portable analogue synthesizer with a flexible modular voice architecture introduced by Electronic Music Studios (EMS) in 1969.
EMS released the product under various names. Logos printed at the console's front left (see photos) say "V.C.S. 3" on the most widely sold version; "The Putney (VCS 3)" on the earlier version; and "The Synthi (VCS 3) II" on the later version "Synthi VCS 3 II".