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Author Topic: Cat 702?? Brad Miller Administrator Posts: 17775 From: Plano, TX (36.2 miles NW of Rockwall) Registered: May 99 posted 01-06-2003 09:22 AM                     I'm with you Steve, I wish Dolby would go back to the cat 699/700 bulb. I've got a cat 701 in a theater that only runs evening shows and is already maxed out after about 2 years. (I should specify that this is the only 701 I have seen require maxing on the supply in such a short amount of time though.) It still tracks good, but was recently faulting and when I realigned it I had to max it out to achieve level. How much time do you think it has left? On the flip side, I have one of the older style penthouses (can't remember if it was a 699 or 700) at another theater that has been running for 2-3 years on the same bulb. The thing still reads at 0-1, so I'm not going to change it until I see the error count increase or the thing dies! When it does finally go, it will take the projectionist there a whopping 2 minutes to handle it.  |  IP: Logged Steve Guttag We forgot the crackers Gromit!!! Posts: 12814 From: Annapolis, MD Registered: Dec 1999 posted 01-06-2003 11:31 AM                     One of the many issues with the visible red LEDs is that they are unpredictable...some fade fast...others are marathon runners. For a penthouse reader...the choice is obvious, the conventional exciter lamp is the only smart choice...the CCD doesn't do as well with the monochromatic light source and the stability of the LEDs down right suck. The switch from the 700 to the 701 defies any sort of logic unless you had an agenda to sell more LEDs...hmmmmm Steve  |  IP: Logged Ken Lackner Phenomenal Film Handler Posts: 1907 From: Atlanta, GA, USA Registered: Sep 2001 posted 01-06-2003 04:31 PM                     I take it from your discussion and preference towards the cat 699/700, that red LED's are not going to be necessary with digital tracks as they are with the optical track? If that's the case, why did they even switch?  |  IP: Logged Steve Guttag We forgot the crackers Gromit!!! Posts: 12814 From: Annapolis, MD Registered: Dec 1999 posted 01-06-2003 05:15 PM                     There is NO good reason to have switched the digital reader lamp whatsoever. Just bad engineering at work and possible red LED agenda going on....Dolby doesn't get to sell you EPT lamps every two years the way they get to sell you their red LED. Do you REALLY believe that the cyan tracks are going to come this year or ever? Red LEDs aren't going to be needed for the analog sound either. I've said it before and I'll say it again...cyan tracks are a dumb idea whose only hopes are to offer the industry inferior quality. Steve  |  IP: Logged Steve Kraus Film God Posts: 4094 From: Chicago, IL, USA Registered: May 2000 posted 01-06-2003 05:57 PM                    What was the difference between the 699 and the 700? Both were halogen lamps, no? And 701 and 702 are red LED with just a difference in power source? Has the CCD and optics been the same all along?  |  IP: Logged Mark Gulbrandsen Resident Trollmaster Posts: 16657 From: Music City Registered: Jun 99 posted 01-06-2003 07:58 PM                     Steve K, I believe that both the lamp power supplies and the ccd end of things were much more complicated in the 699....all vastly simplified in the 700 for the mass market. I still prefer the white light cat 700 over any of the scanners out there. Who the heck buys their EPT lamps from Dolby?????? That is a pretty common lamp available fomr many lamp wholsalers for about half of their price. Never had any poor results with doing it the cheaper way. MArk @ CLACO  |  IP: Logged Steve Guttag We forgot the crackers Gromit!!! Posts: 12814 From: Annapolis, MD Registered: Dec 1999 posted 01-06-2003 09:33 PM                     The CCD has been the same up until the late model Cat 701 and then Cat 702...it is more sensitive to allow lower LED current to allow yet longer life. As to the Cat. 699...it used a different lamp than the Cat. 700. The Cat. 699 lamp was a single source lamp too...Gilway. I believe it was 12V versus the EPT's 10.8. The EPT is a more common lamp (even has the ANSI code to it). The Cat. 699 used fixed precision machining for alignment of the optical path...the Cat. 700 was less precise but allow you to adjust the CCD board to get things near perfect. The Cat. 699 had a better film path and superior damping, in my opinon. The Cat 700 had a much better flywheel than the Cat. 699. If the Cat. 699 had the more massive flywheel it would track even better. Steve  |  IP: Logged Ken Lackner Phenomenal Film Handler Posts: 1907 From: Atlanta, GA, USA Registered: Sep 2001 posted 01-07-2003 07:50 AM                     quote: Do you REALLY believe that the cyan tracks are going to come this year or ever? Red LEDs aren't going to be needed for the analog sound either. I've said it before and I'll say it again...cyan tracks are a dumb idea whose only hopes are to offer the industry inferior quality. OK. Let's assume the cyan tracks will happen someday. My question is, are the red readers only necessary for the optical track, or at that point will they be needed for the digital tracks as well?  |  IP: Logged John Pytlak Film God Posts: 9987 From: Rochester, NY 14650-1922 Registered: Jan 2000 posted 01-07-2003 09:33 AM                        Both the Dolby Digital and SDDS digital tracks are normally printed with DYE images, with no silver redevelopment required, since the readers (tungsten or red LED sources) were designed to read dye images. They don't depend on having silver in the image like tungsten lamp analog readers. Cyan dye analog tracks eliminate the need for redevelopment of the soundtrack area, and leave NO silver in the track, and will require a red LED reader: http://www.dyetracks.org http://www.kodak.com/US/en/motion/support/dyetrack.shtml  |  IP: Logged Christopher Seo Jedi Master Film Handler Posts: 530 From: Los Angeles, CA Registered: Jun 99 posted 01-07-2003 11:01 AM                     Ken brings up an interesting point. Why is it that tungsten lamps are fine for dye-only digital tracks but not for dye-only analog tracks? Are the digital reader CCDs insensitive to the lamp's infrared, where solar cells are susceptible?  |  IP: Logged John Pytlak Film God Posts: 9987 From: Rochester, NY 14650-1922 Registered: Jan 2000 posted 01-07-2003 11:19 AM                        I'm not sure of the spectral response of the particular photoreceptors used for the digital readers, but the photocells in most analog readers have significant sensitivity in the infrared portion of the spectrum, where film dyes absorb little energy. Using a high intensity red (LED) light source puts the peak reader sensitivity right at the peak spectral density of the cyan dye, even with a cell that "sees" infrared energy (e.g., S-1 response peaks at 800 nanometres). Even so, noise is typically higher, requiring effective noise reduction like Dolby SR. There are cells sensitive to mostly visible light (e.g., S-4 sensivity curve peaks at 400 nanometres with almost no IR sensitivity), but they have much less quantum efficiency than the S-1 response cells. So noise becomes even more of an issue. It's likely that for a digital reader, where you are just trying to discern "on" and "off" bits, the quantum noise of the detector is not as much of an issue as with analog sound. So a CCD sensitive to visible light can be used with either a red LED or a tungsten light source, and easily discern bit images made of only dye. Information on photodetectors: http://www.cem.msu.edu/~cem835/Lecture04.pdf  |  IP: Logged Steve Guttag We forgot the crackers Gromit!!! Posts: 12814 From: Annapolis, MD Registered: Dec 1999 posted 01-07-2003 04:10 PM                     With digital, you are looking for a distinct level difference, at one point a digial processer will declare a level high or low...not somewhere in between. If you hook up the Dolby DRAS program and look at the "Histogram" section you will see it has two camel like humps. the left one is where the bright bits are the right one is where the dark bits are. The CCD is actually too sensitive to UV...all of the readers that have white light exciter lamps on them have UV filters right in front of the lamp. If you look at the histogram of a RED light reader you will see it has trouble deciding on the right "hump"...it never really peaks. Steve  |  IP: Logged

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