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Author Topic: Silly bulb mount - those crazy Kneisley Xenex's! Monte L Fullmer Film God Posts: 8367 From: Nampa, Idaho, USA Registered: Nov 2004 posted 11-27-2006 01:50 PM                     Screen is 45x90 with a 435 ft throw. No, there's 3ph out there, but the owner got literally suckered in a system that definitely wasn't designed for a drive-in of this size - maybe for a smaller screen and shorter throw.... Lamphouse that uesd to be out there was as ORC that ran 4200w bulbs, but heard that the rectifier went kaput, thus the owner purchased equipment out of a SMALL closed-down drive in-which included a Century SA and a BALCO platter. Drive-in used to have one of those large reel underslung transports that the projector was mounted on a platform directly above the takeup reel. Thus, when the rectifer went, the main operator out there 'conned' the owner to buy this other booth so he wouldn't have to fuss with film rewinding... The rectifier is also a Kneisley but the smaller model with maximum current output of only 95 amps being attached to this XENEX I What's real bad also is the screen faces eastward, making those sunset starts horrible being of the lesser wattage bulb (and having a Century with no water cooling to allow higher wattage bulbs - that was also purchased in that sucker deal...). I've set the taps on that rectifier as high as I dare go to get decent light out to that screen (and on scope using B&L CS attachment I with a 5.97inch backup) When I started to service this drive-in (and do some shifts out there as well..), light output was horrible due to the OSRAM that was in there was almost burnt up-mainly due to that anode cap was all but black, allen set screws were all corroded in, and the cable was almost crystallized and brittle. Thus, knowing that I couldn't get that cap off and no parts floating around for that XENEX, was the easy choice of just getting a bulb with the attached anode cable and do the direct connection as posted above. With this conversion, I managed to get a little bit of better light out of the thing, but still a far cry of what a 4200w bulb would fire out through that Century. Yeah, I fully agree though with the illumination factor.. -Monte  |  IP: Logged Dave Bird Jedi Master Film Handler Posts: 777 From: Perth, Ontario, Canada Registered: Jun 2000 posted 11-28-2006 01:05 PM                        So long as the i's get dotted and t's crossed, my family and I will be operating a drive-in in eastern Ontario next summer that currently runs with a similar setup to the one Monte describes above. I nearly bought the place 5 years ago during a 2-year closure and at the time, the booth housed those big, beautiful gold Gaumont-Kalee's with Strong 135 3-ph. arclamps (still 3 or 4 of 'em there). The big eastern ice storm occurred during the closure, and though 3-phase power runs right past the building, the Hydro utility plucked the transformers for emergency use elsewhere. A long-time former employee of the drive-in's founder came along and re-opened in 2000, and Hydro was very reluctant to replace the service it had pilfered. So now as we sit, we're looking at about 425 ft. to an 80-foot screen - Balco 5-deck platter running to an XL with Xenex lamphouse and - wait for it - TWO K bulb! Oh, and a Jaxlight. I spent about 8 weekends there this past summer figuring out how everything that's there now ticks. The mission come spring is "clean it up, fix it up, and improve". I'm not satisfied with the brightness for 'Scope and it goes without saying, if we're upping the wattage for 'Scope, then Flat will follow. But believe it or not, the Flat images are decent, clear and brightness comparable to many of the other drive-ins around who mostly use 3K on 50-60 foot screens. As a side note, this lamphouse apparently received the much-debated "Technalite" treatment at time of install. I'd be interested to hear some suggestions on both intermediate steps with this lamphouse, as well as some more permanent suggestions. Realistically, when I go back in the spring to open, I'd like to do some "instant" upgrades (like a 3K lamp) to improve until we can get the proper things done, like 3-phase power and a bigger lamphouse, etc.  |  IP: Logged Monte L Fullmer Film God Posts: 8367 From: Nampa, Idaho, USA Registered: Nov 2004 posted 11-28-2006 03:15 PM                     quote: Dave Bird Oh, and a Jaxlight. *cough* .. *cough* Get a BACP reverse reader immediately and get rid of that Jaxlight to give to your worst competition there. Yea, you definitely need some more horsepower to hit that size of screen with that long throw...2k bulb on a 80ft screen at 400 plus feet?? What were they thinking?  |  IP: Logged Louis Bornwasser Film God Posts: 4441 From: prospect ky usa Registered: Mar 2005 posted 11-28-2006 06:38 PM                        There might be an intermediate step. IF the flat is OK and the scope is bad; then new scope lenses will make a big improvement in the scope. (scope should be 150% brighter than flat) You will want to do this later anyway. As for xenon horsepower; if you can find any single phase rectifiers, you can gang them up to whatever power you need including 6k. I am not impressed with anyone's switcher rectifier. Louis  |  IP: Logged Jack Ondracek Film God Posts: 2348 From: Port Orchard, WA, USA Registered: Oct 2002 posted 11-28-2006 07:51 PM                        Hope you took some notes when you were down here, Dave.  |  IP: Logged Tim Reed Better Projection Pays Posts: 5246 From: Northampton, PA Registered: Sep 1999 posted 11-28-2006 07:57 PM                       quote: Monte L Fullmer to hit that size of screen with that long throw FWIW, the throw doesn't matter, except in regards to requiring longer, and possibly, slower lenses. All else remaining the same, the screen could be 1,000 ft. away and yield the same results.  |  IP: Logged Sam D. Chavez Film God Posts: 2153 From: Martinez, CA USA Registered: Aug 2003 posted 11-28-2006 08:22 PM                       Thank you Brother Tim. I pointed this out for almost 40 years until I got tired of "explaining" this. If you were to measure the light arriving at the screen, it would be the same whether its 40 Ft. or 400 ft., except for the possible loss inside the lens.  |  IP: Logged Monte L Fullmer Film God Posts: 8367 From: Nampa, Idaho, USA Registered: Nov 2004 posted 11-28-2006 08:59 PM                     Thx on this explanation about throws and lenses (slow, or fast and was really never explained in this area of projection)which - and don't mean to drift off topic here, yet it really isn't since we're picking on XENEX lamphouses and to get light to the screen at a certain brightness so one can see the picture here - how can one tell if his optics are indeed slow to getting the light out there to where replacement faster lenses are needed..? thx-Monte  |  IP: Logged Dave Bird Jedi Master Film Handler Posts: 777 From: Perth, Ontario, Canada Registered: Jun 2000 posted 11-28-2006 10:23 PM                        Darn right I was Jack, mental notes anyway. I think there are probably alot of top notch setups, especially among those on boards like this, but I've never seen systems as good as yours. Ticketing, Concessions, Projection, the whole operation just as smooth as silk. We hope to get back down that way in the spring. Thanks for the answers folks, this should be alot of fun, in fact, I don't think we'd be doing it if there WEREN'T things to be done. What were they thinking? Well, the owner's a great guy, worked there for many years and despite having too many things to do already, just couldn't stand to see her closed. Got hamstrung when the 3ph. service was pulled out, wasn't sure he'd make any money at it, so did what he had to I suppose. Really unique place, runs almost predominantly family movies with a more mature second feature all summer, and does very well. We agree that it needs a couple more screens and a much enhanced concession (my expertise). But I'm also a bit of a gear-head, and I'm looking forward to wow-ing the crowd with more light and better sound. And that's more than he'd like to tackle at this point. It's a throwback, of course, even the box office reports are pecked out on a typewriter, and needs a splash of paint here and there. But it was built like a bomb shelter, best of the best back in '53, so it will look very, very good when we're done with it.  |  IP: Logged Tim Reed Better Projection Pays Posts: 5246 From: Northampton, PA Registered: Sep 1999 posted 11-29-2006 04:14 AM                       quote: Monte L Fullmer how can one tell if his optics are indeed slow to getting the light out there to where replacement faster lenses are needed..? Monte, "slow" or "fast" refers to the aperture of the lens, or, how efficient a particular lens is at passing the cone of light. A slow lens has a high f-stop, e.g., f/4. A fast lens would be like an f/1.8. It is related to the focal length and the diameter of the lens. When you get into an exceptionally high focal length lenses, the angle of light they will pass gets narrower and narrower, resulting in higher effective f-stop values. This cuts the available light. The upside is, with higher f-stops, the depth of field also increases, so it's easier to keep the image focused. The converse is also true.  |  IP: Logged Louis Bornwasser Film God Posts: 4441 From: prospect ky usa Registered: Mar 2005 posted 11-29-2006 11:12 AM                        Sam, I am so tired of trying to kill this "long throw" issue, that I won't even respond to it anymore.........of course, you COULD factor in fog, air pollution or low flying aircraft. Louis  |  IP: Logged Monte L Fullmer Film God Posts: 8367 From: Nampa, Idaho, USA Registered: Nov 2004 posted 11-29-2006 02:32 PM                     Thx for this info Tim, for was never taught this. So, basically, if the lenses were removed out of the machine, then throw the light on the screen, the illumination would be the same then. But, whatever kind of lens goes into the machine it has the properties of presenting either a good picture, or a dim picture. So, possibly in the case of this drive-in that I service: The flat is a f/3.50 and the scope is the f/5.97 elements. I've always wonder why the flat is so much easier to focus and keeps the good focus in as well as a better picture than the scope lens would emit. But, also stated above, that the scope needs to be the better picture due to the larger opening of the aperture. Thus, do we need to just get more light out through that longer lens? thx-Monte  |  IP: Logged Scott Norwood Film God Posts: 8146 From: Boston, MA. USA (1774.21 miles northeast of Dallas) Registered: Jun 99 posted 11-29-2006 03:28 PM                        Those sound like focal lengths (i.e. 3.5" and 5.97"), not lens speeds. Most cinema lenses seem to be somewhere in the f/1.7 to f/2.0 range. Switching from an f/2 lens to an f/4 lens would cut the light output by half (one stop) and would mean the difference between 16fl and 8fl on screen (everything else being equal). Question: does an anamorphic adapter change the effective speed of the prime lens?  |  IP: Logged Monte L Fullmer Film God Posts: 8367 From: Nampa, Idaho, USA Registered: Nov 2004 posted 11-29-2006 03:33 PM                     OH...sorry on this ..yes, these are focal lengths not aperture opening sizes...my bad... Yes, the flat lens has a huge aperture opening (like over a f/2 or something-lens having almost the same outside diameter as with the barrel diameter) whereas the scope has a smaller (can't remember the opening) than the flat lens has...(you'd think that the scope backup should have the larger aperture opening...) thx for clearing this up for me....learn something new in here. -Monte  |  IP: Logged Gordon McLeod Film God Posts: 9532 From: Toronto Ontario Canada Registered: Jun 99 posted 11-30-2006 07:10 PM                     Dave would that be the napanee drivein by any chance?  |  IP: Logged

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