Hi guys,

Might be a stupid question but I have some XLR-XLR DMX leads and XLR-XLR speaker leads. Is there any difference between the two?

I needed 2 DMX leads but I have some spare speaker leads, would it be ok to use them?

Thanks in advance,

Mark

dmx cables and speaker cables are totally different. If you are talking about signal (mixer to active cab type leads) cables as opposed to speaker cables (some passive speaker systems have xlr speaker leads) then you can use them over short runs.

to be honest with disco lights you wont have a problem, if you were running 30m down a room then you may get some issues. Just make sure the leads dont have an earth through the xlr plug itself.

passive speaker leads are a heavier 2 core cable which is no use at all.

The only time i have had any dmx issues is with my adj led par cans and my elation par can controller. I have bought a dmx terminator which solved the problem.

Dave is right in what he says above, and if you are doing VERY VERY long runs then the proper stuff is going to give you less faults (the odd fixture doing it's own thing and taking the rest of the chain with it !). Big Wembley style shows with big name artistes cannot afford even one fixture to go wild, so they will only use top grade gear, and cables, fully checked before and after rigging

However, for probably even the largest disco, if the cables are well made up, clean pins n sockets, you can use mic/ speaker cables or make your own from twin +screen.

I've never measured it, but as an example (not a willy out moment !), I run a single DMX channel up one stand, in and out of up to 12 fixtures of various makes, down the other stand, into upto 46 LED par cans round a very large room (old Abbey) (LED's are cheap german ones) and use no terminator !

It all works fine, until a cable breaks obviously, but when the cabling is fine, so are the lights !

I have a selection of cables and plugs, cheap chinese, decent UK, home made from thin signal cable, and never have an issue

Give it a try !

Don't they also use a number of DMX universes and probably dedicated splitter/amplifiers too along the way..



I've found a pair of new DMX Scanners which refuse to work unless you terminate the end of the chain! They've also got reversed polarity too


I've done about a 96mtr run around the school hall once.. 4 dmx lights, rack mount dimmer, 8 kam led pars and had no issues. two lengths were 20mtrs.. The only time I used the 20mtr "dmx" or "audio" lead is to run the audio a long way to remote amplifier for a school playground!

Cheers,

David.

I think the RS485 (the electrial signals used on DMX) standard is a max of 32 items (lights) on the chain.
This is determined by the driver IC's, and isn't a limitation of the protocol or software.

I do try to use DMX cables (as opposed to mic/xlr), and my pre-rigged lighting is wired this way.

The other thing with DMX is that the entire data is resent very frequently- so a rouge signal should be over-written very soon after.
So... some interference may cause visual problems (ie, random colours on LED Par Cans), but this should be reset if the interference is just a glitch.

Jason

They do ! belt, braces and then lots of gaffa tape :-)




Polarity was reversed in the early DMX Abstract kit (twister 4's etc) I just rewired the fixtures sockets to match everything else !

Odd needing a terminator these days, the vast majority of stuff these days (pro & lower end) I thought self terminated through the IC's... could well be wrong though... maybe I've just been lucky !

Possibly on the more expensive kit... quite a few dipswitch setting types will have a switch just to terminate it there instead..


I just terminate with an XLR plug => sorted. Just make sure that I forget to put it away again afterwards, as once someone else helped pack away and probably either dropped it, though it was broken or something... Bah!

The old NJD stuff with 1/4in jack self-terminated, it used the switch on the jack socket. Modern stuff usually doesnt self terminate, though some stuff has a resistor switched in by one of the DIP switches where fitted. This is not the norm.

So is it work keeping hold of the old indian made Datamoon then you think or should I just sell it on again? I think the fan could do with being replaced in it - it is a bit on the noisy side...


Cheers,

David, king of off-topicness!

I've never owned a datamoon, but I think they are quite like the Twister 4, several of which I've had. In which case a standard PC case fan will do the job. Probably less than a pound to buy, then fit with self tapping screws.

You may like to compare BTU (I think that's the term), which is how much air it pushes, obvuosly the higher the better for enhancing the lifespan of your lamp

I think it takes a 24v fan. I'm sure superstardeejay will mention the exact fan type needed - I know it needs to be quite powerful cos they do get quite warm.

This old indian model has a lot of paint peeling from it. not sure if its worth restoring this some way or just passing-it-on..

Cheers,

David

Twister 4/ Moonray/ Moonscan etc is a DC12v 2.6w (KDE1208PTS 1-6) fan as standard.

Search on e-bay for 'abstract' and you should find a replacement fan for £2.99 + delivery. I have just replaced one in a Moonray. The origanal had 2 broken vains and vibrated like a good un. It now runs nice and quiet and cool.