The 400W Venture Lighting Ballast and UHI-S400DD USHIO 400W Bulb

[Guy Grotke]

An electronic ballast, (like the lumenlab light kit electronic ballast), will give you optimum performance with a Ushio S400DD. It will give you a bit more light output than a cheaper core and coil ballast. It will also run cooler than a core and coil ballast.

The Ushio S400DD has about the same performance quality as Osram HQI-TSD-400W double ended, in terms of lumens and color temperature. But the Osram has a smaller diameter outer glass envelope, so it will fit some reflectors and pre-condensor lenses that the Ushio lamp would not fit. I think the Osram also has a slightly shorter arc length, which would get more light through the projection lens. The other big difference is that you can use a very cheap core and coil HPS ballast for the Ushio, but I think you must use an electronic ballast with the Osram.

You do not need a reflector with any lamp, but adding a good reflector will make your screen image brighter. I have a very good spherical reflector, and it adds 22% more light to my screen image. Elliptical reflectors can give you even more light, but the design of such a projector is more complex.