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Topic: Shutting down at night

Ken Lackner
Phenomenal Film Handler

Posts: 1907
From: Atlanta, GA, USA
Registered: Sep 2001

posted 06-16-2002 12:28 AM

Do you turn your amps off before you turn off the breaker to the sound cabinet? What about the monitor? What about the processor? I've never heard of doing that before, but that's what they do at my theater. It certainly could not hurt, but I was just curious as to how necessary it is. Especially turning off the processor. (We have the CP650, and it has a power/bypass button on the front panel rather than behind the panel like previous Dolby processors, but I don't think it's meant to be used as a daily power button.)

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Michael Wohlford
Film Handler

Posts: 17
From: Round Rock, TX, USA
Registered: Jun 2001

posted 06-16-2002 01:01 AM

Why do you want to know? We just use the main circuit breaker panel for all things. Platters, sound racks, projectors, wtc.

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Steven Gorsky
Expert Film Handler

Posts: 146
From: Frederick, MD, USA
Registered: Sep 2000

posted 06-16-2002 01:06 AM

I can't think of any problems with doing that, except whoever opens better make sure they turn on everything. I can see it now, on the walkie talkie - projection, there is no dialog in number 5, only the music. Oops. Worse if no one notices something like an amp not turned on, and a tech get called in thinking its a blown speaker or bad amp, only just to turn it on.

At the AMC I previously worked at we didn't switch off individual things, but one time someone didn't get all the breakers, and missed the one for the exhaust fan. They swore the got all the breakers, so the taped the failsafe switch up so they could run the projector. They had run several shows that way before I got a chance to come and check it out (two seperate theatres in one mall, I was working the other). Needless to say that was one of the breakers that I put a breaker lock on.

Steven Gorsky

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Paul Mayer
Oh get out of it Melvin, before it pulls you under!

Posts: 3836
From: Albuquerque, NM
Registered: Feb 2000

posted 06-16-2002 01:09 AM

At the places I've seen using the CP-650, they either kill the rack power at the breaker panel or the automation shuts the console and rack down. I don't think there's a need to also switch each item off using its own switch--doing so just puts more wear and tear on said switches IMO.

Edit: Who shuts down? At the Caesars Palace Omnimax our Paramount Sound amps stayed on for the entire 21 years that the place existed (minus the occasional power failure)!

Paul
Lame Mercenary Projectionist
"When the money runs out, so does I."

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Brad Miller
Administrator

Posts: 17775
From: Plano, TX (36.2 miles NW of Rockwall)
Registered: May 99

posted 06-16-2002 01:22 AM

Assuming the installers put thought into how they wired things into the breaker panel, a standard policy of mine is:

Power up - hit the top breaker first and work your way down

Power down - hit the bottom breaker first and work your way up

The theory there being that way things are powered on/off in a desired order (like shutting off the amps before the crossover). Not all installations are wired with that mindset though.

I'm with Paul, turning on/off each item using the switch on the unit is just begging for the switch to die prematurely. Bear in mind that any local electrician can change out a breaker in the panel, but only a tech will be able to get inside the piece of equipment and wire around that power button.

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Joe Beres
Jedi Master Film Handler

Posts: 606
From: Minneapolis, MN, USA
Registered: Nov 2000

posted 06-16-2002 01:24 AM

At my past job, we always left the 650 powered up. As far as the other issues are concerned, turning your amps on last and turning them off first will avoid those loud pops that can, on rare occasions, do some damage to your speakers. I'm sure that's one of the reasons why your co-workers power up and down in the sequence they do.

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Dave Williams
Wet nipple scene

Posts: 1836
From: Salt Lake City, UT, USA
Registered: Jan 2000

posted 06-16-2002 01:27 AM

When it comes to really expensive audio equipment, keep this in mind...

ALWAYS... power up your amps last...
ALWAYS... power down your amps first...

If you do this, you will avoid costly speaker repair...

Ever hear that loud pop if you dont? Thats the spirit of the speaker letting you know you hurt its feelings, and wont feel much like coming to work tomorrow.

Also, to avoid any potential power spikes, make sure that all of your amps, processors (unless powered directly by the breaker), digital processors, etc, are OFF when you turn on the main breakers, then power them up, then power up your amps.

Dave

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Ken Lackner
Phenomenal Film Handler

Posts: 1907
From: Atlanta, GA, USA
Registered: Sep 2001

posted 06-16-2002 01:45 AM

Interesting. I've never heard of turning off the processors before the breakers before. For older processors, would this mean opening up the panel and hitting the bypass switch? Or is it OK to just hit the breaker?

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Brad Miller
Administrator

Posts: 17775
From: Plano, TX (36.2 miles NW of Rockwall)
Registered: May 99

posted 06-16-2002 01:57 AM

I think you are just misunderstanding what everyone is saying.

This is the one thing everyone agrees on: Next time you work at the theater, find out which breakers control the amplifiers and mark them (perhaps with a piece of tape). Then just make it a rule that in the morning those breakers are the LAST ones turned on. At night, those marked breakers are the FIRST ones turned off. At night, if you turn off the processor and/or crossover before the amplifiers, you could send a loud BLAM through the speakers and damage them. The reverse can happen in the morning.

The other recommendation is to use only the breakers and not the equipment's power switches. Like I pointed out earlier, my reasoning is that the breakers are cheap and any electrician can change them. That's not the case when the power switch on your equipment dies. Dave is recommending using the power switches on the equipment itself with the reasoning of possible power spikes.

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Ken Lackner
Phenomenal Film Handler

Posts: 1907
From: Atlanta, GA, USA
Registered: Sep 2001

posted 06-16-2002 02:02 AM

To my knowledge, the entire sound system is on one breaker. I know that everything in the sound rack is (processor, monitor, crossover, amps). Not sure about the speakers. In that case, it is my understanding that the recommendation is to turn off the power switches on the actual amps before hitting the breakers. Right?

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Brad Miller
Administrator

Posts: 17775
From: Plano, TX (36.2 miles NW of Rockwall)
Registered: May 99

posted 06-16-2002 02:06 AM

One breaker??? ONE??? Unless you're running a low powered system, that's just not enough to wire things to code, as standard 110v outlets are only rated for a maximum of 20A. How many amplifiers do you have in the rack? What brand/model are they?

The speakers are connected to the amps. There is no such things as powering down a speaker.

And yes, if everything is really only on one breaker, then you have no other alternative than to power down the amplifiers directly, then power off the breaker. That sounds like a poor installation to me though.

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Ken Lackner
Phenomenal Film Handler

Posts: 1907
From: Atlanta, GA, USA
Registered: Sep 2001

posted 06-16-2002 02:18 AM

OK, let me clarify. The breakers that we use on a nightly basis are the ones on the console. We never touch the breaker boxes on the wall. I suppose the box on the wall could have one breaker for each peice of equipment.

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Steven Gorsky
Expert Film Handler

Posts: 146
From: Frederick, MD, USA
Registered: Sep 2000

posted 06-16-2002 03:05 AM

One breaker is enough if it is controlling a contactor. It can also be wired so one breaker will shut down the console and the sound rack.

One more thing, don't QSC amps (and some others) have some kind of protection on the speakers when powered down?

Steven Gorsky

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Manny Knowles
"What are these things and WHY are they BLUE???"

Posts: 4247
From: Bloomington, IN, USA
Registered: Feb 2002

posted 06-16-2002 05:00 AM

Here in The Bahamas – where power surges and total electrical failures are quite common – we shut EVERYTHING down at night.

Shut the actual things off. Then open the breakers.

Turn the sound rack on top-to-bottom (amps last)
Turn the sound rack off in reverse (amps first)

There is no power button on the CP-45 and the one for the CP-500 is inside so nobody shuts them on/off, except with the breaker.

Yes, it's true...this is murder on the actual breaker switches. I guess I replace maybe two switches per year. On the other hand, I've never had to replace an amplifier or a processor. Not a bad trade-off.

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Jamie Sanson
Film Handler

Posts: 33
From: Port Macquarie,NSW, Australia
Registered: Feb 2002

posted 06-16-2002 07:17 AM

Most of todays amps have protection for input/output DC offsets at turn-on/turn-off including QSC amps.So it dosen't matter if you don't switch them of at the amp.

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