hello- I'm trying to modify a Lightware mvp800 with a new light source. I need a bulb small enough and bright enough. I also have a lightware vp800 , which uses a single-ended 400w halogen and works quite nicely. Is there anyone with any experience with these small halogens. I only have a 4 x 5 inch compartment. Any other suggestions would be appreciated. thanks- Kurth
Hi, converting a projector designed for a metal-halide light to a halogen bulb would be quite a lot of work... I'm curious as to why you would want to...
I have experience with using HID and halogen lights in the pro audio / performance lighting area. You would be facing 2 big problems.
First the heat. A halogen would put out significantly more heat than the original metal halide bulb and would probably melt the internals or crack the LCD, you would also need to use a di-chloric reflector to prevent the heat from being reflected into the LCD.
Second, a metal halide light is a point source meaning that all the light comes from a spot in the middle of the light about 1-1.5mm in diameter. The lenses would be focused on this spot and switching to a halogen where there is a huge filament would require completely refocusing or replacing the optics. It would be cheaper to buy a new projector probably.
Third... most projectors use a lower than line voltage for their halogen filaments... like 82 volts or sometimes 24 volts. This allows for a thicker shorter filament that is less fragile to shock. This would require either a large transformer (600 watts atleast) or a complicated power supply.
All in all, I don't think it can be done.
I have experience with using HID and halogen lights in the pro audio / performance lighting area. You would be facing 2 big problems.
First the heat. A halogen would put out significantly more heat than the original metal halide bulb and would probably melt the internals or crack the LCD, you would also need to use a di-chloric reflector to prevent the heat from being reflected into the LCD.
Second, a metal halide light is a point source meaning that all the light comes from a spot in the middle of the light about 1-1.5mm in diameter. The lenses would be focused on this spot and switching to a halogen where there is a huge filament would require completely refocusing or replacing the optics. It would be cheaper to buy a new projector probably.
Third... most projectors use a lower than line voltage for their halogen filaments... like 82 volts or sometimes 24 volts. This allows for a thicker shorter filament that is less fragile to shock. This would require either a large transformer (600 watts atleast) or a complicated power supply.
All in all, I don't think it can be done.
If you can, replace that halogen with a metal halide bulb. They ran cooler (at the same wattage) and are brighter.
Raf
Raf
re.
OK guys- here's the plan. The Lightware mvp800 uses a MH 250w bulb that cost $300- that's only for a piece of glass 3" long x 1/4" dia and has a 500 hour life- I find that absurd , to say the least. The projector runs the lcd w/o the bulb in place -i.e. there is no feedback and it has a built-in condenser. My plan is to construct a separate lightengine that mounts in the 4" x 5" bulb compartment and has it's own power connection and cooling system isolated from the lcd. I'd prefer to use a MH but I can't find one small enough , the aquarium MH's are about 5" long. I thought about using a normal mogul-based MH and illuminate from the end but that would put the source 3 or 4 inches from the built-in condenser and make the reflector design very difficult. I also have a lightware vp800.The difference is that the vp uses a small 400w single-ended halogen! It's not a point source because the filament is about 3/8 " long and it projects a nice image. I think the reason is the thick built-in condenser ( about 1"thk) That bulb has only a 50-100 hour life but only cost $6.There are many projector models that use this type of bulb, usually sold in the late 90's( dukane infocus,etc.).Also the bulb is not isolated from the lcd except by the condenser. There are other small( 3") single-ended halogens with 2000 hour lifes that only cost $10. I'm open to your ideas. If anyone knows of a MH that would be suitable or if the idea of illuminating from the end w/ a mogul MH sounds better , or another solution not discussed, please feedback. thanks alot- Kurth
OK guys- here's the plan. The Lightware mvp800 uses a MH 250w bulb that cost $300- that's only for a piece of glass 3" long x 1/4" dia and has a 500 hour life- I find that absurd , to say the least. The projector runs the lcd w/o the bulb in place -i.e. there is no feedback and it has a built-in condenser. My plan is to construct a separate lightengine that mounts in the 4" x 5" bulb compartment and has it's own power connection and cooling system isolated from the lcd. I'd prefer to use a MH but I can't find one small enough , the aquarium MH's are about 5" long. I thought about using a normal mogul-based MH and illuminate from the end but that would put the source 3 or 4 inches from the built-in condenser and make the reflector design very difficult. I also have a lightware vp800.The difference is that the vp uses a small 400w single-ended halogen! It's not a point source because the filament is about 3/8 " long and it projects a nice image. I think the reason is the thick built-in condenser ( about 1"thk) That bulb has only a 50-100 hour life but only cost $6.There are many projector models that use this type of bulb, usually sold in the late 90's( dukane infocus,etc.).Also the bulb is not isolated from the lcd except by the condenser. There are other small( 3") single-ended halogens with 2000 hour lifes that only cost $10. I'm open to your ideas. If anyone knows of a MH that would be suitable or if the idea of illuminating from the end w/ a mogul MH sounds better , or another solution not discussed, please feedback. thanks alot- Kurth
Kurth,
Search through Mathias' posts. He has been working on this problem for some time and has some novel ideas as well as some pictures of his efforts.
The halogen is a bad idea especially in a small OEM projector which will not have enough air space and will not have been designed to deal with that much heat. You may destroy the projector plus the halogen will have wrong color balance making everything look yellow.
Hezz
Search through Mathias' posts. He has been working on this problem for some time and has some novel ideas as well as some pictures of his efforts.
The halogen is a bad idea especially in a small OEM projector which will not have enough air space and will not have been designed to deal with that much heat. You may destroy the projector plus the halogen will have wrong color balance making everything look yellow.
Hezz
The Lightware VP800 has a 400w 36v halogen as it's light source. I like the idea of using a par30 reflector with a commercial hmi or mh. My question is if the halogen is too hot and not the right color temp, how does it work so well in the vp800? This is also the bulb used in the infocus 550 & 560 which also appear to put out a good image.Also does anyone know any sources for small HMI or MH bulbs ? thanks again
Well, I tried to use halogens with my sony projector and I managed to cool down 150w halogen somewhat ok with 2 x 8cm fans going on full (although all the plastic parts around that are are now charcoal), but the image was darn dim (150w halogen has about 1/4 of the lumens a 150w HID has), and with 250w halogen I managed to crack the UV filter and burn rest of the plastic parts to dust or something like that... and of course constant temp alerts from the projector, no matter how many fans I hooked the system up... so... be prepared to have lots of heat to cool down if you are going for the halogen way. I actually have finally a 150w HID coming in post at monday... cant wait to get it (25% more lumens then the 250w halogen, cooler then the 150w halogen 😀) !
Oh and the light color is a bit to the yellow on those so the blue shades tend to be a bit dim with halogens.
Regards
HB
Oh and the light color is a bit to the yellow on those so the blue shades tend to be a bit dim with halogens.
Regards
HB
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