Abstract: In a gas-blast switch with a compression device with a compression piston and a compression cylinder, at least one of which can be moved by the drive during the cut-off process, starting from a cut-in position, reducing a compression space delimited by them, the initial quenching gas pressure is increased in that the compression piston is moved toward the compression cylinder in advance. In order to take advantage of the magnetic effect of the break current, an armature which can be moved by the magnetic field of a stator which can be excited by the break current is provided, producing a pressure influence causing the advance movement of the compression piston via a compression chamber.