Abstract: A tape tension control system is provided which controls the rotation of two tape reels to maintain substantially constant tension of the tape over its full length for all operational modes. The device utilizes inputs from two reel tachometers and a tape counter-roller for controlling the torque applied to each reel by AC induction motors. The tape counter-roller effectively measures the linear velocity of the tape which is driven by a capstan and the tachometers measure the rotational velocity of each reel. Appropriate logic circuitry, supplied with these velocity readings, enables the system effectively to sense tape diameter on each reel for providing the necessary torque to each reel to maintain uniform tape tension. This system provides for rapid start of the reels to allow for fast lock-in of the capstan and also controlled starts in fast modes such as rewind and fast-forward to prevent high stresses on the tape.