Exemplary illustrations of a supply tube, e.g., for a painting system, such as for supplying compressed air to a turbine in a rotary atomizer or for supplying an atomizer with a fluid medium, such as paint or a rinsing agent, are disclosed. An exemplary supply tube may include an upstream tube section and a downstream tube section. The upstream tube section may have a larger inner cross-section than the downstream tube section. A painting robot is also disclosed, which includes an exemplary supply tube.