I'm not up on the Durst heads, but I'm an electrical engineer. I'd bet that the bulb is a low voltage tungsten , maybe halgen. Likely 12V or 27V or something in that range is needed, and stabilized here is best. If it is anything like my Omega, there is likely a line voltage fan, either 120V, or, since Durst is Italian, I believe, it may be 220V. There may also be 120/22V panel lights to show the settings of the dichric filter settings.
Good luck, hope this helps. Do not be afraid of taking 'the hood off' and looking inside for bulb type, which will guide you on that voltage, and any markings on the fan, or other bulbs if they are present.