Film-Tech Forum ARCHIVE: Christie ch20 to ch10 conversion

This is topic Christie ch20 to ch10 conversion in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.

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Posted by William Hooper (Member # 71) on 03-04-2004, 01:50 AM:

What's needed to convert a ch20 to use 1,000w bulbs (basically creating a ch10)?

The reflector is different, is the condensor lens also different?
Can the CH20 rectifier be easily modified to operate a 1,000 w bulb?

Posted by Mark Gulbrandsen (Member # 72) on 03-04-2004, 08:32 AM:

Why would you want to do that? More light is better than less light anmd you can defocus the lamp to get to 16 to 18 fl anyway. If your screen is relly tiny consider using a three bladed shutter on the projector. But......

A CXL 1000 should fit right in there. Same threads and all. The big problem is if your rectifier will go that low in amperage. If you have 208 three phase it might, but if you have 230 volt 3 phase forget it.

Mark

Posted by John Pytlak (Member # 331) on 03-04-2004, 02:19 PM:

I agree. If you have "light to burn", cash it in on a real on-screen advantage like a three-blade shutter (no shutter flicker), better illumination uniformity (backing off on lamp focus), or a better depth of focus (by stopping down the lens). Or even a gray screen, to get better contrast ratio.