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Author Topic: Help with sound c/o wiring Don Furr Jedi Master Film Handler Posts: 509 From: Sun City, Ca USA Registered: Nov 2002 posted 07-07-2003 10:26 PM                     I'm finishing my new booth and I'm bogged down on the wiring for my sound change over switches. Can anyone email a wiring plan using a Smart Mod 2b? It defaults to projector #1 until you short and hold the ground/change over lugs on the 2b. I prefer monentary push to change switches. Thanks in advance for any help. Don dndcine@mindspring.com  |  IP: Logged Tim Reed Better Projection Pays Posts: 5246 From: Northampton, PA Registered: Sep 1999 posted 07-07-2003 10:57 PM                       Just use a Potter and Brumfield latching relay. One coil latches the contacts, the other releases it.  |  IP: Logged Paul G. Thompson The Weenie Man Posts: 4718 From: Mount Vernon WA USA Registered: Nov 2000 posted 07-08-2003 01:23 AM                     Tim mentioned the easiest way to do it. By the way, you can trigger the latching relay off the change-over douser in most cases.  |  IP: Logged John Anastasio Master Film Handler Posts: 325 From: Trenton, NJ, USA Registered: Sep 2000 posted 07-08-2003 05:30 AM                        I had a Smart processor that worked the same way. I wired a latching pushbutton switch to the contacts and mounted it in a small project box that I could hold in my hand. It had Velcro on the back and I'd just stick it to the back of whichever machine had the next reel ready, then just grab the box to make the changeover. The wire was long enough to be able to watch for cues and it was convenient because it was so moveable.  |  IP: Logged Dave Macaulay Film God Posts: 2321 From: Toronto, Canada Registered: Apr 2001 posted 07-08-2003 12:34 PM                     The P&B mechanical latching relay costs a bunch but it's probably the best solution. The problem is with the picture changeover, unless you use momentary buttons it's hard to give the short pulse required - most changeover coils burn out in no time if you try leaving the power on. With 120V changeovers and a 120V latching relay there's no problem, SPST buttons and the relay are all you need. Unless you want separate picture and sound changeover switches of course... maybe a classic foot pedal system? You can avoid the expensive relay using 3 2C relays and momentary buttons, one relay wired with electrical latching plus a pair following the changeover buttons and activating the picture changeovers plus toggling the sound changeover relay. Unlike the mechanical latch relay this will "forget" it's on projector 2 if the power hiccups though. Plus relay life might be a problem as the latching relay will be powered half the time unlike the pulsed mechanical one.  |  IP: Logged Daryl C. W. O'Shea Film God Posts: 3977 From: Midland Ontario Canada (where Panavision & IMAX lenses come from) Registered: Jun 2002 posted 07-08-2003 01:27 PM                        The least expensive way to do it would be to use a DPDT switch at one machine and a SPDT switch at the other, and have separate sound and picture changeover controls. If you wire it something like this, you can changeover (the sound) between each projector (from either projector), regardless of either switches current position. If you label your switches like this: Switch 1 (DPDT) 1A1 1A2 1Y1 1Y2 1B1 1B2 Switch 2 (SPDT) 2A 2Y 2B Then wire as follows: P1 to 1A1 to 1B2 P2 to 1B1 to 1A2 GND to 2Y 1Y1 to 2A 1Y2 to 2B There's the two dollar solution... plus you'll be able to do seperate sound and picture changeovers (with the addition of a seperate picture changeover button that you probably already have) which will allow you to do changeovers even more seemlessly.  |  IP: Logged Paul G. Thompson The Weenie Man Posts: 4718 From: Mount Vernon WA USA Registered: Nov 2000 posted 07-08-2003 02:13 PM                     I don't think the latching relays are that expensive. The "ice cube" style is probably the cheapest.  |  IP: Logged Steve Guttag We forgot the crackers Gromit!!! Posts: 12814 From: Annapolis, MD Registered: Dec 1999 posted 07-08-2003 07:07 PM                     The last time I price checked the P&B KB or KBP style relays they were knocking over $150 a pop and special order items in most places. I agree it is the best thing going for that sort of function. Then again, many of the newer processors now take pulsed c/o commands (CP-500 and CP-650 do) so just a couple of $10-15 jobbers will do you and there is no chance the processor will be out of sync with the projectors. Steve  |  IP: Logged Tim Sherman Expert Film Handler Posts: 125 From: North Ridgeville, OH, USA Registered: Aug 2000 posted 07-09-2003 02:54 AM                        Doesn't the mod 2b use a pulse system? Nothing like being able to connect to the automation.  |  IP: Logged Don Furr Jedi Master Film Handler Posts: 509 From: Sun City, Ca USA Registered: Nov 2002 posted 07-09-2003 05:32 AM                     Hi Tim........ No, the Mod 2-B is a "make" and hold on the ground/c/o lug. My old Smart 300 was a pluse but not this one. Thanks for all the help with my question. I think I have enough knowledge to proceed. You guys are great!!  |  IP: Logged Matthew Bailey Master Film Handler Posts: 461 From: Port Arthur,TX Registered: Sep 2000 posted 07-09-2003 11:51 AM                     I know where you could get some switches & relays for maybe free. From bowling equipment techs & mechanics that work at bowling alleys. They shold have spares which they use with pinsetters & ball returns. Maybe you can ask someone in the forum at www.bowltech.com  |  IP: Logged Tim Reed Better Projection Pays Posts: 5246 From: Northampton, PA Registered: Sep 1999 posted 07-09-2003 01:28 PM                       Humm... I wonder what that field pays?  |  IP: Logged Daryl C. W. O'Shea Film God Posts: 3977 From: Midland Ontario Canada (where Panavision & IMAX lenses come from) Registered: Jun 2002 posted 07-27-2003 05:14 AM                        How'd it go Don?  |  IP: Logged Don Furr Jedi Master Film Handler Posts: 509 From: Sun City, Ca USA Registered: Nov 2002 posted 07-27-2003 06:10 AM                     Dayrl.... All finished!! Used a relay system given to me by a friend. I installed c/o buttons on the exciter lamps doors and all is perfect. Now as soon as my second ORC lamp is delivered I'll be completely through. My XL's have 6000 Kelmar arms but I'm resisting the large reel route. Been there done that. Something about the sound of that ding, ding, ding.!!! I come from the "old" school. I was doing changeovers on Supers when I was 14 years old.....I'm 55 now! Thanks for asking. Don  |  IP: Logged Frank Angel Film God Posts: 5305 From: Brooklyn NY USA Registered: Dec 1999 posted 07-27-2003 09:48 AM                        Don, Congrats....nice when something you put together yourself actually works. I was going to post the circuit I used for my change-over but these guys were faster. I went the relay route also which enabled me to add LED indication at the switch. If I had more room, I would have used sexy lighted switches. I also added a MUTE switch with flashing LED next to the switch and have found that very useful. Because I run lots of old prints, picture change-over remains separated from sound change-over and is switched by on one of those nice, big, macho footswitches. Wouldn't have it any other way. I can't tell you the number of times it was imperative that I let the sound on that last 21 frames of the outgoing reel play after the picture is switched. And how lucky you are to have your own personal oil wells in your booth. Gotta love those XLs! BTW, who needs Kelmar arms when you can run 2000ft reels in those massive Simplex long-play magazines?! The cinema gods say, NEVER apologize for running 2000ft reels. Frank  |  IP: Logged

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