Has anyone experimented with running both the main and spare lamps simultaneously in an OHP?
I have a 3M 6400 panel on top of a 3M 9200 OHP. I am using a sheet of whiteboard paneling for a screen.
When compared to my 19" TV the image is faded and dim - like a brighter OHP would really help - (oops out of money)
Anyway, my idea for making the OHP brighter is to run both lamps at once. When I turn the lamp changer half way between 1 and 2 it appears that the lamps would be sort of centered on the mirror. I can't see the wiring but, there doesn't seem to be a transformer so maybe the existing wiring could be hacked to run both bulbs in parallel. I could add additional cooling to remove the extra heat.
Any comments??
Thanks for your help!
I have a 3M 6400 panel on top of a 3M 9200 OHP. I am using a sheet of whiteboard paneling for a screen.
When compared to my 19" TV the image is faded and dim - like a brighter OHP would really help - (oops out of money)
Anyway, my idea for making the OHP brighter is to run both lamps at once. When I turn the lamp changer half way between 1 and 2 it appears that the lamps would be sort of centered on the mirror. I can't see the wiring but, there doesn't seem to be a transformer so maybe the existing wiring could be hacked to run both bulbs in parallel. I could add additional cooling to remove the extra heat.
Any comments??
Thanks for your help!
Nope wont work. The fresnels work on a point light sorce, you'll have two hotspots on the image if you use two bulbs. You can however build a light box on top to contain the light that escapes. Something like this will boost the image about 4 times as bright. http://www.diyaudio.com/forums/showthread.php?s=&threadid=52366 8th post down
Clinton
Clinton
A box to trap light leakage does nothing in the way of brightening the image - what it does brighten, it does so at the expense of the image.
The point is to avoid illuminating things like the walls around the image with waste light. To do this, you build a box running from the LCD to the triplet, which catches + hopefully absorbs any light that doesn't remain in the path of the beam.
Making 2 bulbs work in a single lamp:
Short answer - You can't. Using a fresnel to collect your light means you need a point source.
Long answer - it's at least theoretically possible using an expensive beamsplitter w/ 2 fresnels and a reflector, but would suffer from a lot of parasitic light loss, and is of little use compared to simply getting a bigger bulb.
The point is to avoid illuminating things like the walls around the image with waste light. To do this, you build a box running from the LCD to the triplet, which catches + hopefully absorbs any light that doesn't remain in the path of the beam.
Making 2 bulbs work in a single lamp:
Short answer - You can't. Using a fresnel to collect your light means you need a point source.
Long answer - it's at least theoretically possible using an expensive beamsplitter w/ 2 fresnels and a reflector, but would suffer from a lot of parasitic light loss, and is of little use compared to simply getting a bigger bulb.
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