Philips Halogen Dichroic Masterline EXN
Despite the fact that Philips was first to develop low voltage halogen spotlamps in the late 1970s, it was one of the last to market with the popular MR16 versions. The company was adamant that the MR16 dichroic concept was over-engineered for spotlighting, and that its cheaper aluminium reflectors were a better solution. By 1986 it was clear that customers had a different view, so Philips introduced a limited range of its own MR16 lamps and for the rest of the decade sourced most of its requirements from Sylvania. However in 1990, Philips made up for a decade of lost time with the launch of this spectacular 'Masterline' lamp - with greatly improved performance vs all MR16 competitors.

At the heart of the lamp is an axial filament for superior optical interaction with the reflector, burning in a quartz capsule of unusually compact dimensions. This smaller and stronger capsule allowed the gas pressure to be increased to 16 bar, over double that of the competition, for longer life and higher efficacy. The reduced volume also enabled the use of costly xenon gas vs the usual krypton for still greater life and efficacy. Performance is further elevated by making the reflector deeper than usual, for greater light collection.

The result was the first MR16 display lamp having achieving 3200K colour temperature for a whiter and brighter light vs competition, with up to 65% increase in luminous intensity. This immediately put Philips Masterline at the peak of the MR16 market. Another unusual feature of the first Masterline lamps is their unusual base consisting of a metal strap around the glass neck. This bears protruberances rather than the usual inward depressions of the GU5.3 base, and was intended to further improve lampholder retention.
Manufacturer: Philips Lighting
Lamp Power: 50 Watts  
Lamp Voltage: 12 Volts  
Lamp Current: 4.17 Amperes  
Cap Type: GU5.3 Metal strapped base
Bulb Type: MRC-51 MRC-16 in eighths/inch
Bulb Finish: Borosilicate Glass Dichroic reflector
Filament Type: C-8 Axial Single Coil
Atmosphere: CH2Br2 Xenon 16 bar
Luminous Flux: N/A  
Luminous Efficacy: N/A  
Luminous Intensity: 2,250 cd  
Beam Distribution: 38° to 50% peak
Colour Temperature & CRI: CCT: 3200K CRI: Ra 100
Chromaticity Co-ordinates: CCx: 0.423 CCy: 0.399
Lifetime: 3000 hours to 50% survival
Burning Position: Universal  
Overall Length: 43.5 mm 1 3/4"
Light Centre Length: N/A  
Factory: Aachen Germany
Date of Manufacture: April 1990 Date Code: 0D
Original Value: GB £10.77 (1995)
References: 1) Philips Catalogue 1990/91 Germany
2) Philips Price List 1995 UK
3) Philips Datasheet, Masterline Halogen Dichroic Lamps, March 1990
4) Philips Brochure, Masterline Halogen Dichroic Lamps - in a class of their own, April 1990
5) Philips HTO-Training, Incandescent Lamps & Chemical Transport, 2002