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Author Topic: Low cost homebrew red LED light source for cyan tracks Mitchel Monger Film Handler Posts: 6 From: Sagle, Idaho, USA Registered: May 2004 posted 08-10-2005 10:00 PM                     This is a very interesting thread. Yeah, Jeff, I agree, Radio Shack isn't the way to go. I just don't have any other options right now. I only need to get through the next few days. Then I'd like to build a better mousetrap. Thanks for the info about raising the Ohmage. I'll do my best to do that. I read somewhere that they're not much brighter if you push the amperage envelope, and that heat really effects the brightness of the red Luxeons. No time for better details, sorry. I've got to go and finish this project. Nice work Frank! Tell the doubting tech guy to go piss up a rope! I'm looking forward to experimenting with my 4 LXHL-LD3Cs.  |  IP: Logged Bill Enos Film God Posts: 2081 From: Richmond, Virginia, USA Registered: Apr 2000 posted 08-11-2005 12:40 AM                     Nope, we haven't used the white LED at all, if necessary to play an older track we still have exciter bulbs. According to the mfgr specs, the output for the red LED is 635nm So where are all the cyan prints??? We've gotten a few, but certainly not the avalanche that was said to be on the way. If they don't show up soon it's time for exhibitors to sue the bastards to recover the money wasted on yet another fiasco foisted on them to save somebody else a pile of money.  |  IP: Logged Monte L Fullmer Film God Posts: 8367 From: Nampa, Idaho, USA Registered: Nov 2004 posted 08-11-2005 12:44 AM                     intetresting. Homemade "Jaxlights" - hope they run better and cheaper than these goofball units.  |  IP: Logged Frank Jerkic Film Handler Posts: 77 From: Ayr Queensland Australia Registered: May 2004 posted 08-11-2005 05:37 AM                        Opps! forgot to post the front on view of the LED, I have screened the following cyan prints 'Herbie' 'Pacificier' 'Hitchhikers Guide' in my Drive in and also run them in my cinema, they sounded Gr8 and I am not sure if its my imagination but all other films just seem to sound more chrisper and clearer?  |  IP: Logged Jeff Stricker Master Film Handler Posts: 481 From: Calumet, Mi USA Registered: Nov 1999 posted 08-11-2005 06:57 AM                     Good photos, Frank You can't go wrong with some heatsinking. If you don't have a commercial heatsink, folks can use a small chunk of aluminum or copper. BTW: Comments about the techs poo-poo'ing this got a real chuckle out of me. It's hard to argue with something that works and is low cost.  |  IP: Logged John Pytlak Film God Posts: 9987 From: Rochester, NY 14650-1922 Registered: Jan 2000 posted 08-11-2005 07:42 AM                        quote: Bill Enos So where are all the cyan prints??? We've gotten a few, but certainly not the avalanche that was said to be on the way. Some distributors (e.g., Disney) have made the conversion, others are still "testing the waters", sometimes with mixed inventories (after US release, the prints with silver+dye tracks are culled for release in less developed markets that have lower conversion rates to red LED readers). I note that Sony is now on board with "Bewitched".  |  IP: Logged Mitchel Monger Film Handler Posts: 6 From: Sagle, Idaho, USA Registered: May 2004 posted 08-12-2005 01:17 AM                     Showing of "Howl's Moving Castle" a success. Had to use a 50 Ohm 10 Watt resistor (for Luxeon LXHL-MD1D) because other options weren't available. Volume had to be turned up all the way to be at good level. Sound was great except vocal range of the spectrum was a bit too quiet. I'll write more later. Going home and to bed.  |  IP: Logged Jeff Rodenkirch Film Handler Posts: 3 From: Tucson, AZ, USA Registered: Jan 2005 posted 10-04-2005 03:44 PM                        I have had four of the Luxeons running in a theatre in Tucson, AZ for serveral months. After a small mod to the Ultrastereo preamp (2 resistors) the gain is great and I actually get a little more top-end. I'm running them at about 325ma and we've had no problems. The diode and the cap are there so they can run on the AC emergency supply if necessary  |  IP: Logged System Notices Forum Watchdog / Soup Nazi Posts: 215 Registered: Apr 2004 posted 06-18-2007 01:35 PM                 It has been 621 days since the last post.  |  IP: Logged Scott Norwood Film God Posts: 8146 From: Boston, MA. USA (1774.21 miles northeast of Dallas) Registered: Jun 99 posted 06-18-2007 01:35 PM                        Bump. In case anyone cares, we never did build a homebrew LED upgrade for the Western Electric Universal Bases. At the suggestion of the NCS tech who services the theatre, the owner ended up getting Marble "LED Slit Lenses" (type "T") which appear to be an advanced version of the Jaxlight. The LED light source and slit lens come as a single unit and replaced the existing exciter bracket and slit lens. I hooked up an RTA last week and the system is flat to around 4kHz. Sound quality is about the same as it was with exciters on silver tracks, but is much improved with cyan tracks. Trailer reels that mix cyan and silver (and high-magenta) tracks can now be run without needing to adjust the fader between trailers and noise when playing cyan tracks is much reduced. This is probably the most cost-effective solution in case anyone else on the planet is still using these soundheads. I've also seen Jaxlights fitted to these in another theatre (which closed last year), but I was not impressed with the sound quality in that installation. (I can't take credit for either solution...I'm just passing along the info in case anyone is still using this stuff.) I'm sure that Richard Fowler will be thrilled.  |  IP: Logged Richard Fowler Film God Posts: 2392 From: Ft. Lauderdale, FL, USA Registered: Jun 2001 posted 06-18-2007 06:32 PM                     I have used a few of those and found them to be sensitive to R.F. from some ignitors. It is a better fix than a Jaxlite since you are getting new optics as well. I know you are probably not having ignitor problems with the low intensity carbon arc lamps they brought with the Universal bases  |  IP: Logged Luciano Brigite Master Film Handler Posts: 277 From: Sao Paulo, SP, Brazil Registered: Jan 2002 posted 06-18-2007 09:56 PM                     I instaled many of those marble led slit lens, of T,X, and C types and never had a problem with interference from ignitors with them and the response I got on the RTA was around the 6~7Khz with pink noise running on the sound reader. The only problem I had with a few of them was hte power supply that came with them, putting a lot of hum in the system. replaced those with a switching power supply, ( properly grounded!) and it went ok. Also made quite many mods on existing setups using these 3 and 5W red leds on readers using slit lens ( Simplex/century ,Zeiss/Ernemann and Bauers )and reverse readers ( as the Philips PF5/56 and some kalee readers) for the cost, those worked a lot more than expected.  |  IP: Logged Richard Fowler Film God Posts: 2392 From: Ft. Lauderdale, FL, USA Registered: Jun 2001 posted 06-19-2007 07:58 AM                     We also went to Cosel type switchers + a couple of ferrites versus existing exciter power with "regulator" board + proper wire dressing for more reliable results.  |  IP: Logged Gordon McLeod Film God Posts: 9532 From: Toronto Ontario Canada Registered: Jun 99 posted 06-19-2007 09:44 AM                     The problem with them is the uneven illumination across the width of the slit  |  IP: Logged Louis Bornwasser Film God Posts: 4441 From: prospect ky usa Registered: Mar 2005 posted 06-19-2007 10:31 AM                        Uneven illumination equals THD (Total Harmonic Distortion) the same as exciter lamps. Louis  |  IP: Logged

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