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

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."

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.

 

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
 

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.

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.

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

Steven Gorsky

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.
 

Power up
Flip the switch on the wall
Switch the amps one one at a time

Power Down
Switch the amps off one at a time
Flip the switch on the wall

However, the start-up procedure in many sound systems could be an issue. There are some Cinema Processors that can throw a nasty spike into the power amplifier inputs, so you want to make sure the processor is powered up before the amplifiers are. Many amplifiers are time-delay protected, but some are not.

If this is how it is wired up, you have no alternative but to use the on board device power switch.

Dave
 

This is our sound rack:

The crossover doesn't have a power switch, but the CP650, the monitor, and the amps all do. And I believe the switch on the console does control a contactor, because you can hear a loud pop (although not as loud as some theaters I've seen) when you turn on the sound rack, whether each piece of equipment was turned of with its power switch or not.

This is a brand new installation, so I can only hope that all the breakers were wired properly. Although we never touch the breaker boxes on the wall, I'll check those out next time I work.

If your cinema has prescribed a shut-down procedure you should follow it; I wouldn't advise you to go ahead and develop your own way of doing things on your own. You're going to get a lot of good advice here but just make sure it doesn't put you in harm's way.

Not to be a pessimist or anything, but there's that old adage: "No good deed goes unpunished."

There also tends to be politics in the booths and if it looks like you're making a bid for Booth Lead or Supervisor, your coworkers can start doing stuff to make you look bad. The solution to that is to stay in communication with your superiors regarding what you are doing and why you do things the way you do.

As for tweaking the equipment, just make sure that you don't end up creating extra work for your tech. I've had some booth operators who got ahead of themselves by trying to be "helpful" and they created extra work for me and one of them eventually became an usher as a result.

Just some friendly advice.

Thanks for the advice. I'm not tryig to go over anyone's head here. If that's they way they want things done, that's the way I'll do it. I'm just trying to learn what the best way to do things is for the sake of the equipment. This doesn't seem to be too big of an issue, so I'll probablly just drop it. But if there was a policy in place that I felt was harmful for the equipment, I would gather all the facts and tactfully bring it to their attention. As far as tweaking the equipment, I would not do anything without my GM's permission. And I'd show him that I know what I'm doing in. I can admit when I'm in over my head.
 

I was just having premature pangs of guilt and I wanted to make sure I'd done the whole "disclaimer disclaimer" thing. That's all.
 

I'm not sure what brand/manufacturer these sound racks were as most of the text had rubbed off over the years, but I will try to describe them the best I can:

The entire "sound rack" was a self-contained processor, monitor, and amp unit. They were "christie teal" in color, the larger ones sat on the floor (8 amps in the cabinet) and the smaller ones were wall-mounted (3 to 4 amps in the cabinet). The wall mounted ones would swing open for servicing. I have also seen one of these exact same units in the "cinema" our university was interested in restoring at one point. Ultra Stereo perhaps?

I remember one day one of the amps didn't come on when I flipped its corresponding switch. I went to flip it off, then back on and it shot sparks at me!

They have since replaced the processors and such with Dolby CP-50s I believe. Perhaps Mr. Donald Dixon who works at the location now (posted here a few months ago) could give more details.

=TMP=

Without a power sequencer, some processors (CP-50 for sure and, I think, CP-200 as well) _will_ damage speakers if you power up the entire rack at once, unless the amps are QSCs or some other type that has a delayed power feature. The CP-500 and CP-65 do not have this "feature," however. I've never seen a CP-650, so I have no idea if this is an issue (probably not, but...). This is the problem that Paul and others have mentioned.

Brad -- I've seen several booths with one breaker for the entire sound rack. Yes, they all have/had low-power sound systems (and weren't digital).
 

To answer the question, I have had great success with leaving the sound racks on at night, but muted.

 

=TMP=
 

------------------
Jan Hackett
Theater Operations Manager
Extreme Screen Dynatheater
NM Museum of Natural History Foundation
 

However, in the five theatres I've worked for and/or serviced over the past, say, ten years...I've only swapped out one three-phase breaker during a "process of elimination" and, as it turned out, that breaker was not the cause of our problem.

So, in fact, I've never actually had a breaker go bad.

My point? I think the electrician has a point, but the odds don't seem to be very high in favor of a premature failure.

Maybe it's a concern if the breakers are just no darn good for starters. I'm using "Square D" and I think that's a well-respected brand. (But I'm sure someone will let me know if it isn't. )

------------------
~Manny.

"The brown acid that is circulating around is not specifically too good."

-- An announcement in the film, "Woodstock: 3 Days of Peace & Music."

Steve

------------------
"Old projectionists never die, they just changeover!"
 

=TMP=
 

We have the main console which consist of two 36 channel Mackie boards, a separate rack which holds all of the CD players, tape decks, and the patch bay. Another rack in the booth has all of the wireless mic receivers, effects processors, assisted listening transmitters, etc.. In a room about 20 feet away from the booth we have a "processor rack", which holds all of the cross-overs, digital delays, EQ's, and a bunch of other stuff nobody knows what it does. Then finally in a 8'x10' room behind the choir loft (near the baptistry - approx. 80 feet away from the sound booth), we have the "AMP Room". It has three 8 foot high racks loaded floor to ceiling with Crown Macro-Tech amps and all of the cooling fans for the amps.

To turn this whole system on, you simply insert a key into the main console in the booth, then reach over and press the "START" button. It's one of those "sequencer" type of things, that turns on each set of equipment, in a predetermined order, several seconds apart. If you don't have a key.... you get NO sound - PERIOD. We had a really bad problem with the teenagers trying to figure out the sound system, and finally resulted to "total lock down". To turn the system off - same thing - just in reverse. Turn the key in the opposite direction and hit the "START" button again.

Two weeks ago, someone had a wedding photographer in for a wedding and the remote flash the photographer's assistant used was radio controlled. During the photo session before the wedding... every time the remote flash went off - the video screen started rising out of the back of the choir loft.... it's radio-remote controlled (like a garage door opener).

------------------
Barry Floyd
Floyd Entertainment Group
Nashville, Tennessee
(Drive-In Theatre - Start-Up)
 

And now back to why the hell you would care, when it was first installed, it used radio signals to control the movements. This resulted in constant shutdowns during productions in front of live audiences. Now we run off of a hardware network with an additional hardwire backup line in case of failure. Now the only thing that stops the stage is if an actor is smart enough to forget to get out of its way and sets off one of its extremely sensitive sensors.

Dave