A piston compressor includes at least one cylinder for compressing air with a piston arranged such that it can move therein in a compression chamber arranged above the piston in the cylinder. The compression chamber is connected to an inlet arrangement for air to be compressed and to an outlet arrangement for compressed air, the piston compressor being drivable by a first drive device. The inlet arrangement includes a pre-compression device that can be driven by a second drive device with variable power and is used to increase the suction pressure at the air inlet.