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Author Topic: CX20H lamp type Thomas King Expert Film Handler Posts: 119 From: Sheffield, Yorkshire, England Registered: Oct 2004 posted 02-28-2006 04:20 AM                        Hi, I have a Vic5/CX20H lamphouse/silver(non dichromatic) reflector/2 blade shutter/ISCO gold lenses/20m throw/reflective (non perferated) screen. Can someone please tell me which lamp I should be using? In the past I see that people have had 2kw, 1.6kw and 1kw lamps fitted. As far as I can work out, a 1.6kw lamp should be right for me, but I'd like to check the opinion of people who actually know about this sort of thing. Many thanks.  |  IP: Logged Pete Naples Phenomenal Film Handler Posts: 1565 From: Dunfermline, Scotland Registered: Feb 2001 posted 02-28-2006 05:27 AM                     We'd need to know the picture sizes for the advice to be of any value. Throw is largely irrelevant. [ 02-28-2006, 06:57 AM: Message edited by: Pete Naples ]  |  IP: Logged Thomas King Expert Film Handler Posts: 119 From: Sheffield, Yorkshire, England Registered: Oct 2004 posted 03-02-2006 03:41 AM                        Sorry, my bad; I knew I'd left out something important. The visible screen area for anamorphic is 10mx4m (or near as). [ 03-02-2006, 06:57 AM: Message edited by: Thomas King ]  |  IP: Logged Louis Bornwasser Film God Posts: 4441 From: prospect ky usa Registered: Mar 2005 posted 03-02-2006 08:30 AM                        Use 2k bulb. Better warranty and more light. Prob. longer life too, since you are not running at 100%. My experience (osram) is that the 2 k is their very best bulb while the 1.6k is not as good. Louis  |  IP: Logged Thomas King Expert Film Handler Posts: 119 From: Sheffield, Yorkshire, England Registered: Oct 2004 posted 03-02-2006 09:21 AM                        I was under the impression that a 2kw bulb required a dichromatic reflector, otherwise the heat focused on the film would cause meltage.  |  IP: Logged Gordon McLeod Film God Posts: 9532 From: Toronto Ontario Canada Registered: Jun 99 posted 03-02-2006 10:03 AM                     On the horizontal cinemecanica lamphouses you basically have two choices hot mirror and heat filters or a cold mirror (dichroic) and no heat filters and with 3K and larger both heat filters and dichrocic reflector  |  IP: Logged Thomas King Expert Film Handler Posts: 119 From: Sheffield, Yorkshire, England Registered: Oct 2004 posted 03-02-2006 10:45 AM                        I don't have heat filters, so I'm guessing that 1.6kw will do the trick. While I'm here; how often should a xenon of this capacity be rotated? I'm guessing that it's a case of the more frequently the better.  |  IP: Logged John Pytlak Film God Posts: 9987 From: Rochester, NY 14650-1922 Registered: Jan 2000 posted 03-02-2006 12:26 PM                        The need for a heat filter or dichroic mirror is dictated by the amount of radiant energy going through the film frame. Whether you use a 1600 watt or 2000 watt lamp makes no difference if you change the current and/or lamp focus to maintain equivalent light output. I usually prefer to use a larger lamp, and defocus to get better uniformity of illumination, rather than have a smaller lamp maxed out and hot-spotted to get 16 footlamberts in the center of the screen.  |  IP: Logged Louis Bornwasser Film God Posts: 4441 From: prospect ky usa Registered: Mar 2005 posted 03-02-2006 12:54 PM                        On Osram, there is no longer any requirement to rotate; you may do so at your option. Louis  |  IP: Logged Fabrice Dubourg Film Handler Posts: 43 From: Granville, France Registered: Feb 2003 posted 03-02-2006 04:32 PM                     use a 2k lamp but there is a problem with osram on these lamphouse. the wire on the lamp is to near of the miror with an osram and when striking the lamp an arc can go from the wire on the miror and the ignition is then hard!! just compare the diameter of the lam near the bulb between an osram and an ushio.  |  IP: Logged Jerry Axelsson Expert Film Handler Posts: 107 From: Stockholm, Sweden Registered: May 2005 posted 03-04-2006 07:00 PM                     Thomas, we have Vic 5:s with the lamphouse you mention. I recommend that you use 1600w bulbs for them. The light output may not be 100% what one would need in all situations, but 2kW bulbs have a tendency to get overheated and last few hours when we have used them in these lamphouses.(read 1000-1500 hrs for 2kW bulbs) Perhaps this is due to the deep mirror? We have powerful ventilation for our lamphouse, but the problem remains.  |  IP: Logged Demetris Thoupis Phenomenal Film Handler Posts: 1240 From: Aradippou, Larnaca, Cyprus Registered: Apr 2001 posted 03-05-2006 01:49 PM                     Preferably use 2k lamp. I've found USHIO to be more reliable than OSRAM lamps in this lamphouse. Even at 1600W the light output is great as long as the lamphouse is correctly allinged. Is the lamphouse on the proper mounting of the projector or is the lamphouse retrofitted in an older type pedestal? You should be sure that the allingment is correct otherwise use any lamp and you won't get the desired result. D  |  IP: Logged Thomas King Expert Film Handler Posts: 119 From: Sheffield, Yorkshire, England Registered: Oct 2004 posted 03-06-2006 05:01 AM                        Thanks for all your responses; I'm going to order a 1600w because all indications lead to a 2kw at full power being too hot (it's a very dinky lamphouse). I'll take light readings and let you know the results. The way I align the mirror is to take it all the way back, and then center the bright spot, and then take it forward until the bright spot fills the screen. Is this good, bad or ugly?  |  IP: Logged Pete Naples Phenomenal Film Handler Posts: 1565 From: Dunfermline, Scotland Registered: Feb 2001 posted 03-06-2006 06:40 AM                     Is this the tiny little thing that you have to slide the mirror back to change the lamp? If so those are bloody dangerous IMHO, how the hell can you get the jacket over the bulb to screw/unscrew it? You can't! You have to screw the lamp in and out with your fingers, no chance of wearing gloves unless you've got doll size hands 'cos you won't get your paws in there. They do run ferociously hot, anyone who's seen the latest 'Cinema Technology' magazine will see a pair of them behind DP75's on the front cover. We had to go to water cooling on the DP75s with a 1600w lamp, even with healthy forced extraction.  |  IP: Logged Thomas King Expert Film Handler Posts: 119 From: Sheffield, Yorkshire, England Registered: Oct 2004 posted 03-06-2006 08:02 AM                        You do indeed have to slide the mirror back to get the bulb in, and even then it's remarkably difficult. The hole in the mirror will only just allow the crossbar on the lamp terminal through if you tilt it just right, you have to take the lamp out of its sheath beforehand (I protected it by wrapping a lens wipe around it) and wearing gauntlets make you feel like an elephant trying to do brain surgery, not to mention that the anode cable is so long you have to be really careful that it doesn't get near to the douser or frame, otherwise your ignition spark will just arc straight to ground.  |  IP: Logged

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