A mixing console has, for example, eight signal processing channels each for processing audio signals, and indicator units respectively for the signal processing channels. The single stage buck-boost converter reduces the complexity and parts count of the power converter, or electronic ballast, while permitting PFC and DC bus voltage regulation under control of the integrated circuit to maintain constant power on the HID lamp. In one embodiment the bell defines a central opening for receiving a flag stick therethrough. The form is updated based on validation rules.