A manufacturer of modular synthesis modules, based in Lisbon, Portugal. ADDAC offers a wide variety of modules in the Eurorack format, including some unusual functions such as heuristic rhythm generators and an FM radio receiver module with voltage controlled tuning. The lineup also includes several versions of a wavetable oscillator, and a large number of control voltage processing modules. The most notable, but now discontinued, product was the "Voltage Controlled Computer", an Arduino-based microprocessor system, for which a variety of peripheral panels were available, including control voltage inputs and outputs, potentiometer and manual gate panels, DMX interfaces for controlling lighting systems, and an Ethernet interface.