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» Film-Tech Forum   » Operations   » Film Handlers' Forum   » Help with sound c/o wiring (Page 1)

 
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Author Topic: Help with sound c/o wiring
Don Furr
Master Film Handler

Posts: 481
From: Sun City, Ca USA
Registered: Nov 2002


 - posted 07-07-2003 10:26 PM      Profile for Don Furr   Email Don Furr   Send New Private Message       Edit/Delete Post 
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

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Tim Reed
Better Projection Pays

Posts: 5242
From: Northampton, PA
Registered: Sep 1999


 - posted 07-07-2003 10:57 PM      Profile for Tim Reed   Author's Homepage     Send New Private Message       Edit/Delete Post 
Just use a Potter and Brumfield latching relay. One coil latches the contacts, the other releases it.

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Paul G. Thompson
The Weenie Man

Posts: 4718
From: Mount Vernon WA USA
Registered: Nov 2000


 - posted 07-08-2003 01:23 AM      Profile for Paul G. Thompson   Email Paul G. Thompson   Send New Private Message       Edit/Delete Post 
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.

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John Anastasio
Master Film Handler

Posts: 325
From: Trenton, NJ, USA
Registered: Sep 2000


 - posted 07-08-2003 05:30 AM      Profile for John Anastasio   Author's Homepage   Email John Anastasio   Send New Private Message       Edit/Delete Post 
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.

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Dave Macaulay
Film God

Posts: 2005
From: Toronto, Canada
Registered: Apr 2001


 - posted 07-08-2003 12:34 PM      Profile for Dave Macaulay   Email Dave Macaulay   Send New Private Message       Edit/Delete Post 
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.

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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      Profile for Daryl C. W. O'Shea   Author's Homepage   Email Daryl C. W. O'Shea   Send New Private Message       Edit/Delete Post 
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. [Smile]

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Paul G. Thompson
The Weenie Man

Posts: 4718
From: Mount Vernon WA USA
Registered: Nov 2000


 - posted 07-08-2003 02:13 PM      Profile for Paul G. Thompson   Email Paul G. Thompson   Send New Private Message       Edit/Delete Post 
I don't think the latching relays are that expensive. The "ice cube" style is probably the cheapest.

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Steve Guttag
We forgot the crackers Gromit!!!

Posts: 11893
From: Annapolis, MD
Registered: Dec 1999


 - posted 07-08-2003 07:07 PM      Profile for Steve Guttag   Email Steve Guttag   Send New Private Message       Edit/Delete Post 
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

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Tim Sherman
Expert Film Handler

Posts: 124
From: North Ridgeville, OH, USA
Registered: Aug 2000


 - posted 07-09-2003 02:54 AM      Profile for Tim Sherman   Author's Homepage   Email Tim Sherman   Send New Private Message       Edit/Delete Post 
Doesn't the mod 2b use a pulse system? Nothing like being able to connect to the automation.

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Don Furr
Master Film Handler

Posts: 481
From: Sun City, Ca USA
Registered: Nov 2002


 - posted 07-09-2003 05:32 AM      Profile for Don Furr   Email Don Furr   Send New Private Message       Edit/Delete Post 
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!!

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Matthew Bailey
Master Film Handler

Posts: 461
From: Port Arthur,TX
Registered: Sep 2000


 - posted 07-09-2003 11:51 AM      Profile for Matthew Bailey   Email Matthew Bailey   Send New Private Message       Edit/Delete Post 
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

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Tim Reed
Better Projection Pays

Posts: 5242
From: Northampton, PA
Registered: Sep 1999


 - posted 07-09-2003 01:28 PM      Profile for Tim Reed   Author's Homepage     Send New Private Message       Edit/Delete Post 
Humm... I wonder what that field pays?

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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      Profile for Daryl C. W. O'Shea   Author's Homepage   Email Daryl C. W. O'Shea   Send New Private Message       Edit/Delete Post 
How'd it go Don?

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Don Furr
Master Film Handler

Posts: 481
From: Sun City, Ca USA
Registered: Nov 2002


 - posted 07-27-2003 06:10 AM      Profile for Don Furr   Email Don Furr   Send New Private Message       Edit/Delete Post 
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

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Frank Angel
Film God

Posts: 5135
From: Brooklyn NY USA
Registered: Dec 1999


 - posted 07-27-2003 09:48 AM      Profile for Frank Angel   Author's Homepage   Email Frank Angel   Send New Private Message       Edit/Delete Post 
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

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