Help needed with School Lighting setup (dimmer pack addresses)


We've been asked to help a School re-connect the lighting in their Theatre and we're struggling to address the dimmer packs correctly. They've lost their previous tech guy and all the lights were disconnected for testing, so we've been working pretty much from scratch to get it all back up and running.
I don't have much experience (local drama group) but they really need the help for an upcoming Peter Pan performance next month. I'll try and explain the problem as best I can and have taken some pictures in case that helps.

The setup is as follows:-
Showtec Showmaster 48 lighting desk
4x Trancension DDP-405 dimmer packs
14x Pulse Stagepar 108
6x Eurolite par 64
Waterfall effect light
Star curtain
'Beamz' wash light)

I'm used to a console where I can manually patch lights (Z88 Jester) and have no experience with dimmer packs.
We first tried assigning the dimmer packs 4 channels each, then 8 and 16, but I'm unsure if this is the correct approach or if I need to take the fixtures themselves into account. We did finally get some control over the six parcans when using 4 channels per pack but the LEDs are eluding me and I can only control one of them without 'binding' them to the Parcans channel.
I'm pretty sure I've got the addresses wrong and some functions are overlapping.

If anyone can tell me what approach I should be taking to determine each address on the dimmer packs I would be hugely indebted. Also, how would you go about organising the lights across the packs? I was thinking along the lines of having the Parcans split across 2 dimmer packs so we could have individual control, and the remaining 2 packs control the LEDs? If that's even possible.

Here is a picture of the packs themselves. The cables are numbered out of view. (Ignore the addresses here as I was just trying 1,2,3,4 out of desperation!)

(There is also a note stuck to the Showmaster saying about leaving channels 4, 8 and 12 up. I'm assuming these were the previous LED control channels?)


I have a few more pictures of the setup and space if needed.

I realise I'm a bit out of my depth here but I'm keen to learn and really want to help the school. Their drama department has really suffered lately and the kids are losing interest in the Theatre.
Thanks very much in advance if any of you can help me understand all this.


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Fight Leukemia
So the dimmer packs or "shoeboxes" are going to most likely be 4 channels each. You set the dip switches to the binary dimmer channel you want and then the rest of the circuit follow that number sequentially. E.g.- Set the dip switch to 10, first circuit responds as 10, 2 is 11, 3 is 12, 4 is 13.

Every manufacturer is different, I can't exactly tell from your picture, but it looks like they have the bog standard dip switches with some extra buttons added.

The LEDs are probably going to be different. Assuming they're some kind of color mixing LEDs they will have their own DMX data input/output and will not (and should not) be connected to a dimmer. You plug the LED lights into wall power and then take a data line from your console to the fixture itself. It should also have a means to set it's DMX address.

The main trick is that you want to make sure all of your DMX devices have different numbers and without overlap. With the shoeboxes it's going to be 4 channels. Most basic LED lights will have some kind of profile that includes a dimmer channel, R, G, B, maybe a sound active or macro mode. So one LED could have anywhere from 3 to maybe 10 channels of data on its own.

DMX is a daisy-chain network topology which means you take the output from the console and then link it to the first device, then out from that device to the next and so on and so forth. At the end of the chain you should plug in a terminator, which is a little device that essentially just ends that run of devices in an electronic sense.

I'm not familiar with that console, but I would guess then once you have all your devices setup on their DMX channels, you should be able to patch them to desk channels inside that console.


Thanks for the rapid response Stradivarius. I really want to come through for these guys and appreciate the help.

Just to clarify...
The Dimmer packs do have digital displays, so no confusion setting a binary address with switches, thankfully.

Good to know it's probably 4 channels for the dimmers. Setting them up like that gave us the most success earlier.

We do have a dmx terminator at the end of the run.

I think the LED fixture's manual did state they were only 4 channel. They are inaccessable without a tower, so hopefully they are all on the right setting.

All the cabling for the lights runs up through numbered holes below the dimmer packs, including the LEDs, so I'm assuming they did originally have the LED lights plugged into the dimmer packs. I'm not sure it will be possible to re-route them. Is this just bad practise, or is there a physical reason it cannot work?

The console has no screen and is pretty basic. No patching as I know it. I was thinking this is a 'hard patch' situation where the number of channels is pre-determined by the console itself?

If you've any more advice or anyone else can chime in I will be monitoring this thread closely (in the hope of a miracle!).

Additional photos here:
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Thanks again.


Well-Known Member
Hi - it's pretty unusual to power the LEDs through a dimmer, they need "hard power" which is either on or off, so straight back to a switched outlet or something powered by a relay, definitely not a dimmer. You do need to find out the addresses of the existing LEDs and any other fixtures, as you don't want to overlap them with your dimmer packs.

The pulse par cans have a 3 channel mode, where the channels are red, green blue, and a 5 channel mode, where the first channel is a mode selector. I'd guess they're in 3 channel mode, as that's going to be most useful for theatre. Those do set the address by dipswitch. The manuals are available online - a google search (literally on pulse stage par 108) brings them up.

Where in Hampshire (UK?) are you. Judging by the plugs, those look like 13A plugs and 10A IEC (and Pulse is a CPC brand)? It might be worth posting the same question on as there might be a member nearby (it's predominantly, but not exclusively, UK based) who could talk you through it.

Edit: I wonder if the second bank of 24 faders were originally the dimmers, and the top 24 the LEDs. You might be able to deduce something from the desk if you have the manual to hand and go through the patch, such as it is.
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Well-Known Member
Here's a link with user manuals for the lighting console in various languages (I assume). It looks like it has no soft patching capability; the 48 control channels appear to be directly mapped to DMX channels 1-48.

The manual for the LED PARs can be found here. Probably the most useful mode for them would be the three channel slave mode (i.e. DMX512 R/G/B control). A little math shows that you should barely be able to control all the PARs (conventional via dimmers and LEDs) individually with the 48 channels of control you have, but I suspect doubling up on the LEDs is more practical and lets you control the other toys as well, assuming they're DMX controllable.

(And as was said, you don't really want to be plugging the LED fixtures into a dimmer.)


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If you don't know exactly how many DMX slots (3/5/etc) each type of fixture occupies, you might want to start out by setting one sample of each type of fixture at DMX address 001 and plugging them one by one directly into the console and then bring up each fader in turn to determine how the fixture responds.
You are less likely to have DMX address conflicts (overlaps) that way, which will be a great source of confusion.


Well-Known Member
It might be helpful to know what the scribble strips say, as that might give some clue as to how the original addressing was. Since the LEDs won't have been disturbed, it's just the dimmer packs that should need addressing as they were. I think @DrewE is probably right about LEDs being doubled up, so multiple fixtures do the same thing, which, again, the scribble strip may give a clue about.
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Thanks again guys for all of that. Every bit of extra information helps at this stage. I will definately check out the blue room for some local knowledge (I'm located between Salisbury and Bournemouth).

I must have been mistaken about the dimmers actually powering the LEDs and instead they're simply sending direct power up to the Trusses. A gap in my understanding there.

Great idea to try a fixture type one at a time and note the amount of channels used, as well as looking at the scribble strips. Thanks for the manuals, too.

I think we've now deduced that the top row was indeed for LEDs. The previous operator has mentioned 3 channels controlled the colour mixing and a 4th was for overall control. This was repeated for each bank of LEDs, so that makes sense of 4,8 & 12 being 'reserved' on the scribble strip.

I will likely have a few more issues, so I hope it's ok to keep you posted. What a knowledgeable bunch you are!


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Fight Leukemia
Most of the time those consoles will either be in full channel mode, meaning each fader operates a specific dimmer or in 2 scene mode, meaning you get half the channels, but can fade between 2 scenes. It's hard to tell from the pictures what they might've been doing originally, but I'm willing to bet it was in 1:1 mode using all 48. If the LED's are indeed doubled it might be in 2 scene mode, which makes it a little easier if you're changing scenes in a play.


Renting to Corporate One Fixture at a Time.
It’s most likely not in their budget but it sounds like y’all need to get someone in for a few days that knows lighting and electrical and set the facility back up. You have a ton of variables and lots of unknowns but for a few hundred to hire a local guy would save you and the facility much heart ache.


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Those Showmasters can record (limited number of) scenes, and you can fade from one scene to the next, so you don't have to frantically reset faders as you go like the old days. I agree, someone to look over it would be immensely helpful - that's why I suggested re-asking on the blue-room. I'm pretty sure there are some members in that general area. If I were nearer, I'd be tempted to take a look for the price of a pint, but it's a bit of run for me from Caterham.


That's kind of you to think like that guys. I'll get on to the blue room. I'm really only the secondary guy who they brought along, so I've no idea of budget. I'm guessing there isn't much. This is all a learning process and it feels like a month could be cutting it short with a production coming up.

It's frustrating knowing they had a working setup not long ago.

I'm pretty confident with the programming itself once we have control.
I'll try to book another hour this week to look at it, as time is limited in the space. Anything else that's good to note down or photograph would be good to know.
Thanks again.


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If someone could come up with 250 bucks and a donated PC or laptop, the educational package of ETC's nomad will
give you all the functionality of a state of the art lighting desk. 1024 available dmx addresses, full programming and patch control.
You could always plug the old desk in when they need basic "lights on " "lights off" in the space.

It would be easier to learn the nomad moving forward and give you much more flexibility. There are literally thousands of old PC's
and laptops sitting in closets in this country capable of running it.

It might not solve the immediate problem, but moving forward would put you lightyears ahead


Good idea. I did see a laptop sitting in the booth actually and was thinking about recommending MagicQ as I've had a play with the software at home. Maybe Nomad could be a better option.

It might be more appealing to the students as well. Kids these days have no fear of software and they could even work on some projects at home.

Is Nomad much better than MagicQ, or easier to set up? As you said, software may not solve our muddle with the LEDs but the ability to actually patch would be helpful. I'll do a bit of research.
I'm still confused about the power delivery to the LEDs and how they're wired up.

(Great little cars, those!)


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Both have a bit of a learning curve. They're neither that hard to pick up. I found etc slightly easier because it was nearer to the Strand I'd learnt on but really not much in it. Both do training (when they can) and l think chamsys are in S'o'ton so nearer to you than etc in West London (Acton). Both have very good support and both have presence on online forums. Download both sets of software and see how you get on.


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  1. LED fixtures require one hookup for power (220v) and another for control (DMX). The LED power comes from the mains.
  2. Tungsten fixtures require only one hookup for power but that power goes through a dimmer module of some sort.
  3. The dimmer module requires a hookup for power (220v) and another for control (DMX).
  4. The lighting console (desk) requires mains power and a connection to the network of DMX control lines going to your fixtures
  5. Your installation of fixtures needs a map of DMX addresses assigned to each fixture.
    1. Each of your shoebox dimmers are allocated an address for each separate channel they can support (looks like yours are 4 each). You use switches on the shoebox to tell it where in the range of 0-512 that you've allocated its 4 addresses
    2. LED fixtures, like shoebox dimmers, are allocated a range of addresses in the same 0-512 address space. You set the address using the LED fixture's controls. One of the things you can set is the fixture's operation mode. Some modes are limited and only need a small number of addresses while others allow more of the fixtures features to be controlled and those modes require more addresses.
    3. Your map of addresses for your installation will have 4 addresses for each shoebox but you have to decide which addressing mode you are going to set for each LED fixture so you can allocate the right number of addresses. You set the base address of the allocated range into each LED fixture using its controls

The dimmer modules and LED fixtures are all "looking and waiting" for a command from the console that is addressed in its allocated range. Tungsten fixtures are controlled when the shoebox detects a command from the console that is addressed to one of its 4 dimmers. The command includes a value from 0 to 100 that is interpreted by the appropriate dimmer (1 of 4) to be an intensity value. The dimmer varies the power to the fixture to make the lamp glow at the appropriate intensity.

LED fixtures also "wait and look" for a DMX address in its allocated range. Each brand/model fixture uses its own scheme for determining which of its allocated addresses does what. You should be able to find an online spec or manual for the LED fixtures that has a table in it that defines the fixture's addressing modes (how many addresses it will use) and what each address in the range controls (red, green, blue, intensity, strobe rate etc).

Your console has various capabilities. In the simplest terms, each fader is patched to control one or more DMX addresses. Each address is sent a command with a value corresponding to the position of the fader. A simple way to use this mode of operation to control an LED is to assign 3 faders to 3 addresses in one LED fixture (eg 210, 211, 212) corresponding to its Red, Green and Blue addresses. Manipulating the faders will cause the LED fixture to mix those colors at the level of the fader. All 3 at 100% gives you white. All three at 50% gives you white at half of the intensity. etc

This is all just a general explanation to hopefully get you started. You first have to straighten out your installation wiring and assign each fixture and shoebox it's address and mode of operation. Then you can get on to the console programming.
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That's really very helpful, thank you Les for going through all that.

Slightly concerning responses from the Blue Room regarding safety/insurance etc. Apparently the dimmer setup looks a bit worrying and I shouldn't be messing with any of this.

I'm thinking during pat testing the fixtures were just reset/defaulted to an incorrect mode/address and are now out of range, as when we arrived everything was connected as they'd been using for years (for better or worse).

Knowing this, access to the Trusses could be tricky as their Tower is not something I am going anywhere near, and relaying the information up to their handyman will surely get confusing.

I'm starting to think getting someone in is at least worth mentioning now. It's just tricky to broach these things as an underling who's really only meant to be the programmer! (I'll definately be bringing up MagicQ/Nomad, though, as I think there's scope to engage the kids there and I'm more familiar with the format).

Thanks again,


Well-Known Member
Some of the guys responding on the blue room are H&SAW experts, some are trainers, they are all very familiar with the implications of UK law around this, so I think their advice is, on balance, probably right.

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