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DMX Connector war


Ben Lawrance

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Hi All,

 

I've just had a rather heated discussion with a collegue about DMX cable, and hope that you guys can give your opinions on the matter.

 

In stock we have a lot of DMX fixtures that have 3pin on them, and only a few with 5. However, when we hire in extra stuff, it is always on 5. I spend quite a lot of time working out what cable is needed to change pins, and change the pin 2 hot / pin 2 cold scenario. We have mostly 3pin DMX cable for this reason.

 

One idea I came up with (albeit an expensive one) is to make up a load of short (10cm ish) jumpers that convert the fixtures 3 pin, to a 5 pin (and doing a phase reverse if needed) so every fixture would now be on 5. Lovely, just need 5 pin stuff between everything. No more fart arsing about with adaptors and phase reversing etc.

 

 

However, my collegue thinks that this is a bad idea, as if the jumpers get lost were screwed. He's also concerned about the cost of such idea.

 

 

What are the views of the Blue Room. Would you make jumpers, or stay with the 3-5's, phase reversers etc.

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I used to make up two short 3 to 5's, and cable tie them to the mains lead, so when powered up, the correct type was within a few inches of where it was required. It didn't stop people swapping the IECs of course - but worked quite well. I have to admit that I just have a pile of polarity reversers and 3 to 5 barrel style adaptors in the tool box now - less effort!
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Have you thought about actually replacing the fixtures DMX sockets? I had a few smoke machines that were all on 3 pin so I just opened up the unit and replaced the socket, its not a hard job to do, it's cheaper and the are no little cables to get lost... However do check your warranty on the equipment! Wouldn't want you to be converting your gear only to find when it goes wrong you have not got a leg to stand on! :P
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However do check your warranty on the equipment! Wouldn't want you to be converting your gear only to find when it goes wrong you have not got a leg to stand on! :P

Yup - that would invalidate just about any warranty you could find.

(Assuming the kit is still IN warranty, of course!)

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Depending on construction you may struggle to do a phase reverse as well as swapping to 5 pin though Chiefy.

 

One of these interesting ones, certainly if you do make the change, make it clear if you dry hire your kit, other people may be expecting the non standard connector.

 

I've seen jumpers done many times, cable tied to various bits. I've also interestingly seen them on LED pars with right angle XLRs before, as a lot don't seem to have enough height for a full connector if they are pointing straight down.

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We too have suffered this problem.

 

Both the mixture of fixtures with varying connectors and the converters going "walkies" mysteriously.

 

Our biggest culprit is our 2.5K "city colour"s from Fine Art.

They were supplied with 3 pin XLRs on a cable which connect to another unknown 3pin cable..

So, were "forced" into 3pin mode.

 

This some times is and some times is NOT a problem.

 

If were out with our strand dimmers, macs, or coemar fixtures these all feater 3 AND 5 pin connectors so we just spec all cables to be 3 pin.

 

The problem arises when we take some of our other items, such as some of our DMX DA's are 5pin only, our DMX wifi system is 5pin only and some desks are 5pin only, also the lightjokey usb converter.

 

All other jobs we take 5pin only.. (ie all without the city colours or one other cheap 150watt mini robotic)

 

I have to admit I DO like the obvious which was stated above of cable-tie'ing the relavent converter to the device.... gonna suggest this to warehouse manager tomorrow!!

I can see some will go missing here and there but at least it greatly reduces the problem and a visual check will quickly determine whether the "kit" is complete or not.

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If you are worried about stresses on the cable tied to the yoke, put a 'pig tail' in. I doubt I can describe it, but obvious once you see it. Sometimes seen where earth bonding conductors are attached to water pipes and the like.

 

If anyone is still interested, I'll try to photograph something tomorrow.

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Just to think this could have been sorted out a few years ago, where a 'standard' was agreed upon, and all manufacturers conformed.

 

Where did the +ve and -ve swaparound on the XLR originate?

 

Makes an arse out of the whole standard.

 

3 pin, 5 pin, P2+ P2-. The age of technology......... Can't beat it!

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Just to think this could have been sorted out a few years ago, where a 'standard' was agreed upon, and all manufacturers conformed.

 

Where did the +ve and -ve swaparound on the XLR originate?

 

Makes an arse out of the whole standard.

 

3 pin, 5 pin, P2+ P2-. The age of technology......... Can't beat it!

 

But it WAS all sorted out and laid down in a specification, but remember a specification is not a law, more of a guideline: A lot of kit was already rolling off the production lines beforehand. I understand that before the DMX512 was finalised, that Martin / Abstract had 'standardised' on 3 pin with the pins the 'other way around' other users half followed the pending standard with having the right pins but a different connector. in the End the manufacturers that did it the other way were a bit subborn to the bitter end, but then if your company has just spent thousands on a P.C.B. that has the connections a certian way, they aren't going to give up that easily. The decision to go with 3 pin, for the low end stuff I imagine was driven by the market it was supplying, every DJ has a few 3 pin XLRs in the back of the van. bless, they even though they were doing us a favour by putting 3 pin on the units. At least it's not as bad as some of the very early DMX units, with 6 1/4" TRS jack!

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