HPL

Overview

HPL stands for High Performance Lamp and refers to a family of compact tungsten-halogen lamps developed in 1994 by Ushio in close collaboration with ETC according to their design specifications; today, they are also manufactured by companies such as Osram/Sylvania and EiKO. The HPL is not a standalone luminaire, but the light source: it was specifically designed for the ETC Source Four family (profile spotlights, Source Four PAR, Fresnel, Junior, among others) and is closely matched to their elliptical reflector.

A characteristic feature is the very compact filament, which concentrates the light into a small, defined point. In conjunction with the Source Four's optical system, an HPL delivers significantly more usable light per watt than older ellipsoidal lamp types.

Technical Specifications

• Lamp Type: Tungsten-halogen (low-voltage and mains voltage variants)
• Base: G9.5 (two-pin ceramic base) with integrated heatsink base
• Common Wattages: 375 W, 550 W, 575 W, and 750 W
• Voltage Variants: including 115 V, 120 V, 230 V, as well as low-voltage versions (e.g., 77 V)
• Color Temperature: Standard version approx. 3250 K (approx. 3200 K for 230/240 V standard versions); Long-Life versions approx. 3050 K
• Lifespan: Standard version approx. 300-400 h; Long-Life versions approx. 1500-2000 h (lower color temperature as a trade-off)

The integrated heatsink base is part of the lamp design and ensures defined thermal conditions. Current versions (Ushio HPL+) use a ceramic heatsink base that maintains its electrical insulation properties better over the lamp's lifespan; older designs used a metallic base. When replacing the lamp, the heatsink is changed as a unit with the lamp.

On-Set Usage

HPL lamps are the standard light source for Source Four profile spotlights in theater, studio, and film/TV. Their small light source makes them ideal for sharply defined beams, gobos, and precise light shaping. According to the manufacturer, a 575 W HPL in a Source Four delivers a light output roughly equivalent to a 1000 W profile spotlight of older design, with lower power consumption and less heat generation.

Relevant for practical use: The Long-Life variant (lower color temperature, longer lifespan) and the Standard variant (higher color temperature, shorter lifespan) should not be mixed in the same setup to avoid visible color temperature differences between fixtures. When changing lamps, as is customary with halogen lamps, avoid direct finger contact with the quartz glass; grease from skin contact can shorten the lifespan.