3 pin DMX

Shawncfer

Active Member
Okay, So I've come across a little problem.

And yall are all probably gonna laugh at me :oops:

So I've been designing for this show, and I got everything set up how I wanted it. But the other day, I say an "output" for dmx. And I knew the facility already had some rotators, but no power supply. I (the theatre) had some money to spend, and I figured hey, why not get the power supply and throw these bad boys up there on the first electric right?

So I did. :-D

Problem: I was installing them today. And well, it was a mis-read. DMX INPUT not OUTPUT. So I can hook up a board from backstage but I cant run annything with DMX without running a new cable.

So I've been trying to trouble shoot all day, trying to figure out a solution before I get my butt chewed out because I spent some money for nothing. And I had two ideas. One was run a dmx up to the catwalk. Which would be easy, but if I can do plan B, that'd be my preference.

Plan B, So, my sound board has a snake running from the board and some of the inputs are backstage, perfectly located where I would love to have dmx. So I was wondering, If i have a 5 pin output, could I get a converter to make it 3 pin, run it through the 3pin XLR, then convert it back to 5 pin on stage and hook it up the power supply?

Maybe?

And also, I noticed theres no DMX output on the power supply (Apollo Smart Power 75w), so does that mean this should go last in my chain? I cant hook up anything AFTER the supply?

I know this was a long way of putting it, but I appreciate the help guys!
 
Problem: I was installing them today. And well, it was a mis-read. DMX INPUT not OUTPUT. So I can hook up a board from backstage but I cant run annything with DMX without running a new cable.
The gender of the panel-mount connector should have been your first clue. With DMX, "the male always goes home," home being the console. Likewise, "females have all the power, and males always want the power."

The building is likely wired one of three ways:
1) Booth DMX Input goes to dimmers' DMX Input A and Stage DMX Input goes to dimmers' DMX Input B, and dimmers are set to take either or both on an HTP basis. This is the only "proper" wiring, but means that the Stage Input cannot be used as an output.
2) The Booth DMX Input loops through the Stage DMX Input, then onto the dimmers.
3) The Booth DMX Input and the Stage DMX Input are both homerun to the dimmers, where they are two-fered on the same dimmer input.
Both 2&3 are incorrect, but you could, with an A5F-A5F turnaround or cable, use the Stage Input as an Output. IF you're going to do this, it IS STRONGLY ADVISED that you use an opto-isolator immediately after the Stage "output."

Plan B, So, my sound board has a snake running from the board and some of the inputs are backstage, perfectly located where I would love to have dmx. So I was wondering, If i have a 5 pin output, could I get a converter to make it 3 pin, run it through the 3pin XLR, then convert it back to 5 pin on stage and hook it up the power supply?
Many will argue, but I've done this successfully many times, with and without audio on the same snake. Most multi-pair audio snakes are made with 110Ω data-grade wire. Prepare yourself to go to battle with the audio dept. I had a soundman tell me he could hear the DMX going through his snake, but he didn't notice it when he didn't know I had done it.

And also, I noticed theres no DMX output on the power supply (Apollo Smart Power 75w), so does that mean this should go last in my chain? I cant hook up anything AFTER the supply?
Correct. The Smart Power 75w must be the last device on that stream. One way around this would be a two-output opto-splitter just before the power supply. Or a four-output, inexpensive D-Split. You're also going to want a 4pin Terminator for use with that power supply, or everything on the stream, including your dimmers, could go wonky. In my opinion, that power supply should not be sold without the terminator, as the output is not isolated from the DMX input.

Now that you're working with DMX toys, you'll want to buy or build a DMX Tester. See DIY DMX: Demux, Protocol Converters, etc..
 
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Yeah I know, I should've checked it first. But I just saw DMX on the side of the stage and figured, oh, I can run some DMX from here. I mean, I just think it's weird to have a DMX INPUT backstage.

Okay cool, so thats what I'll do, Just buy a couple converters and I'll be good to go. Thanks!
 
Plan B, So, my sound board has a snake running from the board and some of the inputs are backstage, perfectly located where I would love to have dmx. So I was wondering, If i have a 5 pin output, could I get a converter to make it 3 pin, run it through the 3pin XLR, then convert it back to 5 pin on stage and hook it up the power supply?

Will it work? Probably. Is it proper? No. Are you going to get a lot of crap from the sound department? Probably. Is it reliable? Debatable.

Since you have an alternative (running a cable from the catwalks) I wouldn't use this method. If it was a pinch and that was the only solution and the "show must go on," sure, we've all been in that situation. But since you have an alternate method, I would use as last resort.

My $.02
-Tim
 
Many will argue, but I've done this successfully many times, with and without audio on the same snake. Most multi-pair audio snakes are made with 110Ω data-grade wire. Prepare yourself to go to battle with the audio dept. I had a soundman tell me he could hear the DMX going through his snake, but he didn't notice it when he didn't know I had done it.[/URL].

Most audio snake cable is NOT 110 ohms. Manufacturers seldom even measure the impedance of audio cable, because it isn't important for audio. Running DMX through audio cable of any type might work sometimes, but doing can make for unreliable lighting control.

Whether or not it interferes with the audio system is determined by the quality of both the cable, and the equipment connected via the snake. If the common mode rejection of inputs is not good, there will be noise.
 
Agreed. And I can see situations when someone from audio who doesn't know what is going on sees a cable running from the multi into the booth, thinks "What the **** is going on here, and unplugs it.
 
I run DMX through an audio snake all the time. If this is for an installed rig in a theatre I wouldn't do it, but for portable applications you might as well give it a try. If it doesn't work then you'll have only wasted 2 minutes and learned something. As far as someone unplugging it: Communication is an important part of any relationship.
 
Well I hope I don't upset some people, but I went ahead and did it.

It worked fine, and yes its a theatre, not a touring show or anything, but its up today and down next Wednesday. So not to big a deal. Everyone who should need to know knows. And just to make sure, I gaffed a couple pieces of paper near by screaming DO NOT UNPLUG! And anytime theres a reheral or show or anything going on on that stage, the stage manager will be right next to it and she knows nobody touches it either. So I hope all works out okay!
 
I mean, I just think it's weird to have a DMX INPUT backstage.

Or to make focus go a lot easier by having the board onstage...or because you don't have the crew to run the show so the SM is running the board as well from the stage......
 
Darn, wish I'd thought of that, Sean and Grog12. With the board backstage, Shawncfer wouldn't have needed to run DMX through his mic snake!:twisted:

'Course, then he'd have the problem of running a video camera's signal through the mic snake so he could see the stage from the front. (I've done that too, and don't recommend it.:()
 
Darn, wish I'd thought of that, Sean and Grog12. With the board backstage, Shawncfer wouldn't have needed to run DMX through his mic snake!:twisted:

'Course, then he'd have the problem of running a video camera's signal through the mic snake so he could see the stage from the front. (I've done that too, and don't recommend it.:()

Not nessecarily, depends on where his SM console is, he might get a clear..ish view of the stage.
 
Not nessecarily, depends on where his SM console is, he might get a clear..ish view of the stage.

Its totally possible to run lights from the side of stage, if SMs call the show from there, then im pretty sure as long as you can hear, you can run the board. Also, in a pinch, you can run a cued show from anywhere (the basement if you really want), so long as the SM can see the show... While sitting watching the show, I tend to look at the screens anyhow because various things on stage pull my attention from the task at hand, and when you have a cue every 3 seconds for an entire 3 minute song that can be a real problem.
 
Also, in a pinch, you can run a cued show from anywhere (the basement if you really want), so long as the SM can see the show

Disagree. If there is a problem (power failure, etc), the board op needs to be able to see what is on the stage and see what lights are working and where the actors are in case he/she needs to improvise.
 
Disagree. If there is a problem (power failure, etc), the board op needs to be able to see what is on the stage and see what lights are working and where the actors are in case he/she needs to improvise.

I didnt say it was ideal. The fact is, it is POSSIBLE, but should not be done unless there is a really good reason. I cant think of a good one off of the top of my head, except for possibly a situation where there are multiple spaces all controlled by the same board. Having run a show like this, it is not fun, and generally involves a lot of video links (3 rooms, small rig in each, only one dimmer rack and board available to use, and nowhere to sit in those rooms so i was in a 4th with the dimmers, 3 42" flatscreens, 2 speakers, an amp rack, and 3 computers, which means HOT!!!, and another where the board was rackmounted in a storage closet, and I basically looked out the door and watched for hand signals from a buddy who would wave when someone came up to the podium). In the OP's situation, I would run a DMX line from the catwalk to the rotator, as it seems a bit silly to put yourself in such a situation when you have other options. Im not qualified to comment as to the code situation where the OP is, but generally all this type of run takes is tossing a cable from the cat to the deck, and then hooking it to whatever batten has the device, and then dressing the cable out of the way on the stage. Not hard, no possible issues from the noise boys, and decent sightlines maintained.

Also, if there is a power failure, your improvisation is going to be figuring out which emergency lights best light the actors, and hoping they find them. ;)
 
Disagree. If there is a problem (power failure, etc), the board op needs to be able to see what is on the stage and see what lights are working and where the actors are in case he/she needs to improvise.

Many proffessional houses would disagree with you KeeponTruckin...most notably Cirque...several of their Vegas shows "lighting booths" are nothing more than glorified closets with video feeds of the stage.
 
Many proffessional houses would disagree with you KeeponTruckin...most notably Cirque...several of their Vegas shows "lighting booths" are nothing more than glorified closets with video feeds of the stage.

By choice, the LD on Australian Idol and So You Think You Can Dance runs the show from outside the studio. I believe it has more than a little to do with being in a place that the choreographers can't get to...
 
Many proffessional houses would disagree with you KeeponTruckin...most notably Cirque...several of their Vegas shows "lighting booths" are nothing more than glorified closets with video feeds of the stage.

Sure, where they can also rehearse for a year and find/fix any possible problems that might occur. And at least there is a video feed
 

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