A heater system includes a heater bundle and a power supply device. The heater bundle includes a plurality of heater assemblies and a plurality of power conductors. The heater assembly includes a plurality of heater units, each heater unit defining at least one independently controlled heating zone. The power conductors are electrically connected to each of the independently controlled heating zones in each of the heater units. The power supply device is configured to modulate power to each of the independently controlled heater zones of the heater units through the power conductors.