An air/fuel mixer system of a combustion chamber of a gas turbine includes at least one compressed air intake swirler, the swirler having a central axis of symmetry, and a fuel injector including an injection head having an axis of symmetry. Each injector is mounted in the corresponding swirler with aid of a guide mechanism, so that the axis of symmetry of the injection head is off-center with respect to the central axis of symmetry of the swirler. The system can reduce, or even eliminate, combustion instabilities, by injecting the fuel along a particular axis which is off-center relative to the axis of the air/fuel mixer system, inducing a flow of fuel which is no longer perfectly axially symmetrical.