This thesis describes the hardware design of a hybrid system for the composition and performance of electronic music in real-time. While analog circuitry is primarily employed in the generation and processing of sounds, digital circuitrsy is devoted to the exercise of control, under the immediate supervision of the composer/performer. Such a digital vs. analog partition, together with a proper choice of the man vs. machine interface, is intended to satisfy the niuch emphasized musical need for the immediate, real-time interaction between the composer/performer and his instrument.