A media advance system is driven using a fixed-differential, planetary belt drive system. Planetary pulleys, mounted to a mounting structure, orbit a motor shaft as the mounting rotates about the motor shaft. A first planetary pulley is coupled by a drive belt to a fixed pulley. The fixed pulley does not rotate and is aligned to the motor shaft, so the planetary pulley is forced to rotate while orbiting. A second planetary pulley rotates and orbits with the first. An output pulley is coupled to the second planetary pulley by another drive belt. An output shaft is coupled to the output pulley. Drive ratio of the output shaft to the motor shaft is based upon the diameters of the fixed pulley, first planetary pulley, second planetary pulley, and output pulley. Noise is low by using belts rather than meshing gears. Variable differentiation is achieved in another embodiment.