Film-Tech Forum ARCHIVE: Sound format automation question...

This is topic Sound format automation question... in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.

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Posted by Tom Wienholt (Member # 1510) on 12-05-2006, 12:24 AM:

I wanted to know if it would be possible to use the dowser open/close automation terminals to change sound formats. (non-sync to film and film to non-sync at the end of a show) The dowser feed could be attached to the sound format ground, the open dowser terminal to film, and close dowser terminal to non-sync. Is this possible?

Posted by Dominic Espinosa (Member # 2122) on 12-05-2006, 01:00 AM:

Anything is possible however if you have a douser requiring current (as most do) you can't just pulse it from a sound change-over relay because those only close a ground loop in most cases.

What kind of equipment are you working on?
Douser, processor, automation?

Posted by Richard May (Member # 2627) on 12-05-2006, 07:38 AM:

Just take 2 120volt relays and hook up the dowser open pulse to one of the coils and the close pulse to the other one. Then use the dry contacts to pulse the automation.

Posted by Gordon McLeod (Member # 33) on 12-05-2006, 08:50 AM:

just make sure that it is dry contacts that one uses

Posted by Tom Wienholt (Member # 1510) on 12-05-2006, 12:55 PM:

I am using a Christie AM-3 automation and a Dolby CP55 processor.

Posted by Dominic Espinosa (Member # 2122) on 12-06-2006, 02:36 AM:

Is the problem that the AM-3 doesn't pulse the sound and douser at the same time? It's got separate output terminals for both, right?

Forgive my ignorance, but I don't see the actual problem?

Posted by Richard May (Member # 2627) on 12-06-2006, 08:50 AM:

I don't think the AM-3 has the capability to pulse for sound format changes.

Posted by Louis Bornwasser (Member # 3063) on 12-06-2006, 01:45 PM:

That is correct; that is why the 2 120v relays are needed. Louis

Posted by Dominic Espinosa (Member # 2122) on 12-07-2006, 02:08 PM:

Ah, I misread the manual. My bad.

Posted by Tom Wienholt (Member # 1510) on 12-07-2006, 11:18 PM:

quote: Gordon McLeod
just make sure that it is dry contacts that one uses

How can the terminals be tested to make sure that they are dry contacts?

Posted by Richard May (Member # 2627) on 12-08-2006, 12:46 AM:

The dry contacts are the ones NOT hooked up to the coil. You have the wiper in the middle. Then you have a set of contacts on either side. Hook the wiper to your ground on the automation switching on the processor. Then hook the normally open contact to the sound change (stereo, non sync,,etc...) The normally open contact is the one that the wiper is NOT making contact with when the relay is at rest (No power to it). Use one relay for stereo and one for non sync. Splice a wire from your C/O open pulse to one side of the coil on the relay and the other side of the coil goes to neutral. That is your stereo relay. Same for the other relay but use a wire from the C/O close pulse.That relay is for nonsync. Use 2 120volt AC relays

Posted by Gordon McLeod (Member # 33) on 12-08-2006, 09:56 AM:

Richard said "The dry contacts are the ones NOT hooked up to the coil"
no a dry contact is one that has no voltage source present on it
in effect it is a contact that is connected to nothing

Posted by Richard May (Member # 2627) on 12-08-2006, 11:14 AM:

That is true but I'm just trying to make it simple for him to understand the contacts on the relay.

Posted by Tom Wienholt (Member # 1510) on 12-08-2006, 05:44 PM:

Ok, I understand why the use of the relays would be necessary. But, isn't it possible on some automations to use the dowser open close terminals to pulse the sound without the need of the relays. If you have no current hooked up to the dowser feed terminal then why would you need the relays. Basically, does the 120v AC come from the automation itself or from some sort of dowser power supply hooked up to the automation?

Posted by Gordon McLeod (Member # 33) on 12-08-2006, 06:06 PM:

Some automations have dry contacts on the changeover and some are fed with power internaly

Posted by Tom Wienholt (Member # 1510) on 12-08-2006, 06:18 PM:

Ok, that makes sense. Now, how could it be determined whether these automation contacts are dry or not without a manual for reference?

Posted by Gordon McLeod (Member # 33) on 12-08-2006, 07:53 PM:

Put a voltmeter on AC volts and one probe on ground and one on each terminal and pulse the relay and see if there is a voltage there