Systems and methods are described that facilitate providing a user with interchangeable phosphor-coated shells, or envelopes, for generate different shades and intensities of white light from a single UV light source. The interchangeability of the low-cost phosphor-coated envelopes permits the use of a single light engine, which is the more expensive component of a solid state lamp. In this manner, consumers are provided with a greater number of lighting choices at low cost than can be achieved using conventional single-envelope lamps.