This paper presents a research work which investigates experimentally the performance of a tension control system realized by a controlled disc brake. An experimental set-up was established by using a creel with step motor-controlled disc brake, laser distance sensor, yam tension sensor and a 2-unit winding machine. A software was developed in C programming language to read yarn tension and bobbin diameter data and then to control the disc brake by step motor drive. Experimental investigation was carried out with three different cotton yarn counts and unwinding speeds. It was shown that yarn tension changed from full to empty bobbin at a significant amount depending mainly on yarn number and unwinding speed. The feedback tension control system based on adjusting level of braking responded well to short, medium and long term tension variations and enabled unwinding tension control mostly within +/- 1 cN deviation from the adjusted value.