Since when does a 200W halogen bulb cost $250?? Surely there's a cheaper alternative! Is there any reason I can't pick any $10 bulb and Jerry-rig it with the existing cartridge?
Since when does a 200W halogen bulb cost $250?? Surely there's a cheaper alternative! Is there any reason I can't pick any $10 bulb and Jerry-rig it with the existing cartridge?
Pretty sure they're not halogen, they're a special metal halide type that produce a pure white.
For projectors anyway
I know my projector uses a metal halide lamp, but that's because I built it myself. I doubt commercial projectors do however, because the lifetime of a metal halide lamp is more like 40000 hours.
Regarding the cost of the replacement, it's probably the complexity of the reflector that is their justification of the price. You could probably replace the bulb itself if you find one with matching characteristics, but be careful not to get any fingerprints on the bulb or the reflector as that could have rather dramatic effects at these power levels. Metal halide lamps explode.
i know the huge old sony projector i got in 2000 used a metal halide lamp.
(was made in 1997)
It had a 1000 hour lamp life and reached the end of its life a year ago, new lamps were $1000 (expensive due to it being an old model) so i bought a new projector instead
I reset the old sonys lamp hour counter to zero and gave it to my sister to use until it blows up. It's at 200 hours i think now and still going, so 1200 out of 1000 :P
It's almost as if they make the lamps to not last. Then make them really expensive to boot. I wonder why...
I guess it might have something to do with the arc length, but it is still possible to make long life (>4000 h) short arc lamps. My lamp has a rather long arc length, but it isn't really a problem in the projector.
I can clearly see a filament in the bulb.
these are all metal halide
The frosty white bulb bit inside is kinda the givaway
Last edited by Psi; 03-09-2009 at 13:39.
Fused silica only becomes transparent when it's hot. Go go gadget valence band electrons!
There are some projectors that use halogen lamps, but their lamp lifespans tend to be short due to the need to use very high temperatures to get a white enough spectrum. The metal halide lamps tend to work for much longer than their rated lifespan if you are prepared to tolerate white point shift or loss of brightness- there are deposition issues inside the lamp which cause the spectrum of the lamp to shift.
I'm not an expert on these things, this is just my experience with tending and feeding a brace of VJ performance projectors. My experience was that a 1500 hour lamp still worked fine at 3000 hours, but it was noticably yellower than the new one, and not quite as bright.