Abstract: A solvent supply system for supplying a composite solvent is described. The solvent supply system comprises a first supply flow path with a first pump unit, the first supply flow path being adapted for supplying a flow of a first solvent to a mixing unit, the first pump unit operating periodically, and a second supply flow path with a second pump unit, the second supply flow path being adapted for supplying a flow of a second solvent to the mixing unit, the second pump unit operating periodically. The mixing unit is adapted for mixing the first and the second solvent and for supplying a composite solvent. The solvent supply system further comprises a control unit adapted for controlling operation of the first and the second pump unit, the control unit being adapted to prevent at least one of a predefined phase relation and a predefined frequency relation between the first pump unit and the second pump unit.