The Altman 400-MB Magnetic Ballast is a robust, heavy-duty component engineered to provide reliable and stable electrical regulation for 400-watt metal-halide (M-400) lamps commonly used in professional theatrical and studio lighting fixtures. As a magnetic ballast, it operates on established electromagnetic principles, using a core and coil assembly to limit the current supplied to the arc discharge lamp. This technology provides a proven, cost-effective, and durable solution for HID (High-Intensity Discharge) lighting, offering excellent lamp life performance and consistent color temperature when paired with compatible lamp types. Its primary function is to deliver the high initial voltage pulse necessary to strike the lamp's arc and then immediately regulate the current to maintain a stable, flicker-free light output throughout the lamp's operation.

Constructed for the demanding environment of live entertainment, the ballast is housed in a substantial, galvanized steel enclosure designed to dissipate heat effectively and protect the internal components from physical damage and environmental contaminants. The unit is configured for remote mounting, allowing it to be installed away from the lighting fixture itself—typically on a rack, in a dimmer room, or on a pipe grid—which reduces fixture weight and minimizes heat buildup in the immediate performance area. This remote installation capability also centralizes maintenance and improves safety by locating the heavier electrical component separately from the moving or focused light source. The wiring terminals are clearly marked and accessible for secure connections, supporting straightforward installation by qualified technicians.

While newer electronic ballasts offer features like silent operation and flicker-free performance for video, the Altman 400-MB remains a staple in many installations due to its straightforward reliability, ease of service, and high power factor correction, which improves electrical efficiency. It is designed to operate quietly enough for most theatrical applications, with the characteristic low hum of a magnetic ballast being its main acoustic signature. For theaters, studios, and venues with an existing infrastructure built around magnetic ballast technology, or for applications where extreme cost-effectiveness and longevity are prioritized, the Altman 400-MB provides a workhorse component that ensures consistent, dependable performance from 400-watt metal-halide luminaires.