Embodiments of the present disclosure are directed to systems and methods for premixing fuel and air prior to combustion within a combustion chamber. The system includes a plurality of fuel injectors and a plurality of mixing tubes, wherein each mixing tube has a first portion for receiving one of the plurality of fuel injectors and a second portion having a mixing chamber that is configured to mix fuel and air. The length of the mixing chamber varies among the plurality of mixing tubes to allow for different mixing times.