DMX Question

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Before i shell out and buy a DMX splitter unit, is it possible to make a Y cable for DMX, i know that you can do it with mic / line signals, but wasn't sure if it would cause andy problems while using one with DMX?

Reason i ask, while putting in some uplighting at my gig on Saturday, i obviously daisy chained them down one side of the room, then, when i got to the end of the chain, i had to then return the signal cable to the stage area, through the lighting that was on stage and then back down opposite side of the room, and while not too much of a problem to do this, it would have been easier and slightly quicker if the signal was split out of my controller.

[Jiggles]

Sadly you will have to get a DMX splitter as you cannot use a Y cable with DMX.

[DJ James Lake]

I do believe some people have actually used a y-splitter before and it worked.

I would recommend a dmx splitter though.

[csg]

you can NOT use a y split with dmx - whilst there is a chance it will work, it is very likely to cause timing problems caused by reflections in the different length branches which will cause havoc.

so, an active, opto isolated splitter is the best way forward

[Vectis]

so, an active, opto isolated splitter is the best way forward

Possibly the cheapest/most practical but not the best.

The best way forward would be multiple universes but that's probably OTT for a bit of mood lighting.

[csg]

why is the best way forward more universes? Providing you have enough channels on one, and you are not chaining up more than the USITT recommended maximum of 32 fixtures per spur, there is no advantage of any sort to be had from running multiple universes.

My main lighting desk ( Chamsys Magic Q) has 4 direct universe outputs, with another 12 available via artnet ( ethernet) nodes, i will still patch all the fixtures in one area within one universe ( if they fit), even when, as is quite normal, splitters are used to supply each truss with its own dmx spur

The great thing about opto-isolated splitters is that by having multiple short spurs, if problems do arise with cabling or fixture errors, they can only effect a minimal part of the rig, and can not spread futher

The opto isolation is also essential where parts of the rig are connected to different power supplies, where a direct connection can cause ground loop currents to flow, which can cause havoc with control circuits