Systems for producing M bundles of filaments, wherein M?1, include N extruders, M spin stations, and a processor, wherein N>1. Each extruder includes a thermoplastic polymer having a color, hue, and/or dyability characteristic, which are different from each other. Each spin station produces N bundles of filaments that form a yarn. Each spin station comprises N spinnerets through which filaments are spun from molten polymers streams received by the respective spin station and N spin pumps upstream of the N spinnerets for the respective spin station. Each spin pump is paired with one of the N extruders. The processor is in electrical communication with the N*M spin pumps and is configured to adjust the volumetric flow rate of the polymers pumped from each spin pump to achieve a ratio of the polymers to be included in the yarn from each spin station.