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Which XLR Cables should I buy

Discussion in 'Lighting and Electrics' started by Sloanhaus, Nov 23, 2009.

  1. Sloanhaus

    Sloanhaus New Member

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    I am doing lighting for weddings and am using 25 wall washers on average. I currently use cheap cables and it seems like I am always having problems. I am looking to get new cables and want a good cable that will set my mind at ease. Thanks

    Also, is there a maximum distance I can run XLR cables and if so, is there a booster to boost the signal.

    Thanks

    Brad Sloan
  2. achstechdirector

    achstechdirector Member

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    Quickly, you should probably be using a DMX cable not XLR because, if im correct, they are shielded differently. Now that should be of help alone. I think, with the distance issue, that it depends on the equipment not the cable (because I have 150 foot snakes, and they work perfectly. I have never come accross an XLR booster but there are DMX boosters out there that might do the job
  3. icewolf08

    icewolf08 CBMod CB Mods

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    You need to use real DMX grade data cable not microphone "XLR" cable. A few important notes:

    1) XLR is NOT a type of cable it is a type of connector. DMX cables use XLR type connectors; the standard calls for XLR-5 connectors.

    2)DMX is a protocol, not a cable type, but we commonly refer to the cable used to carry DMX signals as "DMX cable."

    3) The difference between microphone cable and DMX cable is not the shielding, it is the wire gauge and impedance. For proper DMX data transmission you need 120Ω impedance.

    In theory you should be able to run DMX over significant distances as long as you use the proper cable. Using off-the-shelf microphone cable from your local Guitar Center or even your local theatre supplier won't cut it.

    While the DMX specification says that you can have up to 32 devices on a single run of DMX, it might behoove you to invest in an Opto-splitter to split your run up into multiple, which will increase the signal strength to every unit. You don't need to split out to 25 individual runs, but even a 4-way splitter could help. You CANNOT just build or buy a "Y-adapter" that you might use for sound systems as this creates the potential for many things to go wrong with your data stream.

    Next up, you probably should invest in some DMX terminators. These are easy to make yourself, and not particularly expensive to buy. Every DMX run NEEDS to be terminated, and this is especially true if you are not using the right kind of cable. Proper termination can often eliminate lots of issues.
    Last edited: Nov 23, 2009
  4. gafftaper

    gafftaper Senior Team Senior Team

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    First off use the search function you'll find a wealth of information already here on DMX and DMX Cable.

    A favorite saying around here:
    "I run DMX over audio cables all the time and it works."
    "Well you can run DMX signal over a barbed wire fence, but it's not advisable."

    DMX cable is data quality cable. It can carry a signal around 1000 feet without any problems. 3 pin XLR microphone cable is audio cable. It has a totally different impedance and the DMX signal degrades very quickly in mic cables. The DMX signal only uses three of the 5 pins in a standard DMX line (the last two were reserved for features that have never been added). The lower end manufacturers decided to keep things cheaper for their clients by using 3 pin XLR connections instead of a proper 5 pin. This works fine If you are a DJ and you only have a few devices located less than 20 feet away from you. But as soon as you try spreading them all around a room or running them from the opposite end of the room, the cheap short cut fails. By the way if you decide to upgrade to DMX cable, whatever you do don't mix DMX cable and microphone cable. You will make things even worse than they are now.

    DMX cables are expensive. A 50' DMX cable will run you a minimum of about $45-$50. Another interesting solution is Cat 5 cable. It's also data cable and available in giant spools very cheaply. Just solder on some XLR plugs and you are ready to roll. Unfortunately it's not very durable so it probably won't work for you. Do a search on DMX and CAT5 for more on this topic.

    Do you terminate you lines? Lack of termination can lead to all kinds of weird issues. Don't know what that means search for DMX termination or DMX terminator.

    Finally you cut down on the length of your dmx run by splitting into multiple lines with a DMX splitter (look out they are expensive). Check out Doug "Dr DMX" Fleenor's website for a lot of good information on what DMX is as well as to buy a splitter.

    EDIT: Dang it Alex, Did you have to sneak in and answer faster than I could? Well I'm leaving my post up anyway because I used the cool Barbed wire quote!
    Last edited: Nov 23, 2009
  5. jjkool

    jjkool New Member

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    To the best of my knowledge optos dont actually boost a signal - especially not to every unit. An opto is simply a bank of differential (rs485) outputs which have been optically isolated from one and other. This means if one chain shorts out or has bad reflections due to non-spec characteristic wire it has no effect on the other chains.

    Y cables can be used, though it isnt recommended... feel free to use em if you still have less then 32 fixtures on your link, but dont cry if the chain shorts and you lose everything :)
  6. jjkool

    jjkool New Member

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    I just looked at the DFD website... the prices IMO are insane! Way to high (for most of it)
  7. Thefoxygranpa

    Thefoxygranpa Member

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    However you get what you pay for. An opto that will continuously work, year after year. He has quite a reputation for very reliable equipment and I find his opto more often than others.
  8. church

    church Active Member

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    if the opto-isolator box is going to work correctly it should be designed with a line receiver chip on its input this will alow hopefully error free recovary of the data+ and data- signals from your console after they have reached the end of the cable. This ensures that the the differential signals gives the maximum signal level to the opto-isolator device. The output of the opto-isolator drives the input of a line transmitter which provides data+ and data- signals again. Each output should have its own line driver which ensures that the differential signal levels for each output are at approximately the same level as they were when they originated from your console.

    Effectively using a decent opto-isolator box will restiore your DMX signal to the same levels you would expect directly from the console. Of cours if you have a cable problem all bets are off.
  9. icewolf08

    icewolf08 CBMod CB Mods

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    A Y-calbe MIGHT work, but there is no guarantee aside from that you WILL have issues. Using a Y can change the impedance of the cable, cause data reflections, and creates the potential for double termination. Just bad, dnot do it!

    So, as said, essentially using an Opto-splitter will restore your output to what the console was sending, thus each fixture should see a better signal if you split up 25 units onto more than one data line. Also, as I understand it, on each output of an Opto you can have up to 32 devices.
  10. Grog12

    Grog12 CBMod CB Mods Premium Member

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    Gaff I think both martin and high end would take offense to your post.
  11. Sloanhaus

    Sloanhaus New Member

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    OK, so I am going to buy a spool of DMX cable and soldier it onto my 3 pin xlr ends that I have purchased. As far as the 2 extra wires, I will just leave those off. I than feel that it is best to split my room into two, so it looks like I will also need a dmx splitter. Thanks so much for all your help.

    Also, can someone please tell me who they recommend for cables. Thanks

    Brad sloan
    Last edited: Nov 23, 2009
  12. Sloanhaus

    Sloanhaus New Member

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    So what you are saying is if the light is 3 pin xlr than it is not a good light to use for long distances and I should be getting one with 5 pin? This is not good as I have bought about 25 lights that were 500.00 each and they are 3 pin...
  13. mstaylor

    mstaylor Well-Known Member

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    I don't think that was what he was saying. The DMX standard is 5 pin but many companies have decided to use three pin instead. What you do want to do is buy cable made for DMX not mic cables. Since your lights are three pin, you could use five wire or three wire cable. At that point if you use 5 pin connectors then you have to make 5 to 3 pin adapters. I would use three conductor wire and clearly mark it so you know what is DMX and what is mic cable.
    As suggested get a opto splitter or if your controller has two universes split your lights that way. With as many lights as you have you are degrading your signal pretty badly. Lastly, make sure you are terminated. You can buy them inexpensively or make them yourself. On Fleener's site there is instructions on how to build them, easy and cheap.
  14. dramatech

    dramatech Active Member

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    You can purchase an Elation optosplitter on Ebay for around $150. It will have four outputs with five pin XLRs and four outputs with three pin XLRs. I have 3 of the units, and have completely disassembled one of the units and checked all of the components and circuit boards for quality.
    All of the integrated circuits are top brand names and the circuit boards and soldering is first rate. The 3 and five pin in each section of four has it's own driver, but is powered by the same supply. The input section and each of the four sections have their own supply and are optically isolated from each other.
    I also have an Irradiant splitter, that has exactly the same circuitry, but the circuit board is a slightly less quality board. I have never had any problems with any of the four, and have had them installed for 4 years in a building with old wiring and prone to lightning hits.
    For what you are requiring, you don't need any thing better.
  15. JD

    JD Well-Known Member

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    The important thing is that there is no "performance" difference between 3 and 5 pin (and wire) DMX. If all your lights are equipped with 3 pin connectors, then so be it. Most of the better equipment is equipped with 5 pin connectors as that is the DMX standard. If I remember my DMX history correctly, the original concept was to use the second pair (pins 4 & 5) as a feedback for error check. For whatever reason it just never happened.
    Some of us have "gone rogue" and use the second pair in the 5 conductor cable for a second universe, or even a sneak way of looping a com line ;) The unfortunate truth is that some equipment with 5 pin connectors don't loop pins 4 & 5 through so that kind of kills it there.
    If you are going with a 3 pin system, there is no need to get anything other than single pair cable. Just make sure it is DMX cable so that it has the proper impedance, and remember to terminate your runs.

    As for opto-splitters, there are cheap ones out there. Probably increases your chance of failure from 0.001% to 0.005%
  16. tcahall

    tcahall Member

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    ...with a shield. Pin 1 of the standard is for ground.

    Tim.
  17. gafftaper

    gafftaper Senior Team Senior Team

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    NOT at all what I'm saying. As Grog pointed out even Martin and High End now cheat and use 3 pin connectors at times.

    Whether it's a 3 pin XLR connector or 5 pin XLR connector doesn't matter. What matters is the type of cable. A 3 pin XLR connector technically does not meet DMX 512 standard, but there's nothing wrong with it as long as it has the proper cable attached. The DMX-512 standard requires 5 pins. But we only use 3 pins. Pins 4 and 5 were reserved for feadback features that have only been used once or twice in the 20+ years that DMX has been around. The low end manufacturers like AMDJ, Chauvet, and Elation said, "Many of our customers are DJ's. Their gear is typically located on stage very close to where they are operating from. If we switch to 3 pin plugs our customers can use cheap mic cables. At that short of a distance, and only running a few fixtures, you really don't need DMX standard cables". Over time it's become more acceptable and now even the big boys put 3 pin XLR connections on their fixtures (The $10,000+ Martin MAC2000 Wash for example has both 3 pin AND 5 pin connectors).
    Last edited: Nov 24, 2009
  18. derekleffew

    derekleffew Senior Team Senior Team Premium Member

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    "Cheaper for their clients"? See the article linked below.

    I think this is a mis-characterization.

    The use of 3-pin for DMX has NOT become more accepted with time, and the trend among major manufacturers is actually towards supplying only 5-pin. Vari-lite has always, and only uses 5-pin. HES used to be solely 3-pin, but current products are now solely 5-pin. Martin used to be only 3-pin, but now includes both on many products.

    Again, one of our members was b*tching about this in print eleven years ago: Whose network is it, anyway? Why the end user is the loser in the DMX512 connector controversy. In 1986, the framers of the Constitution chose 5-pin largely so that microphone cable could NOT be used, so blame the consumer for allowing the practice to continue.
    Last edited: Nov 25, 2009
  19. ship

    ship Senior Team Emeritus Premium Member

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    Totally agreed with Gaff on the 3 verses 5 issue. Do not ever do a Y type splitter for DMX as it will without doubt create a loop.

    A favorite saying around here:
    "I run DMX over audio cables all the time and it works."
    "Well you can run DMX signal over a barbed wire fence, but it's not advisable."

    You can send DMX thru a shop light trouble light type spooler - very rebust signal but overall its a question of the overall length of the cable in use and its imutence - needs to be at least 110 Ohms in range but best at 120 Ohms digital grade cable that's DMX computer language rated.

    Normally such cable is available in either one pair with shield or two pair compliant DMX grade in the only difference being the amount of paired conductors. Overall concept in looking at such three pin cable is a level of quality. Look at the drain/shield wire. If not tinned (silver) it ain't of a digital grade. If even tinned but twisted instead of breaided it ain't within even reasonable standards of digital grade. For a very short run, sure it will probably work given no say power cables near it and good connections but even for single pair cable - that which has +/- data signal and an indexed drain, you will never find a digital grade cable that is not braided and silver tinned wire unless it is drain wire with plastic foil shield around the +/- conductors at best instead. Such cable with metallic foil shiled is normally about the same grade as that with a braided tinned shield about the inner pair or two pair of conductors if four conductor shielded.

    Often DMX cable will have both a foil shield with drain wire and a braided tinned shield wire about it - good stuff and it don't matter how many pair under the jacket. That's quality and much easier to make given the drain wire is all you need to attach instead of trying to get a braided shiled into a terminal. On the other hand at times with such a plastic foil shield, especially with multi-multi pair data cable up to 37 pair or more, that the foil just falls apart once un-bound and you have to spend extra time in just insulating drain wires. This given if index/drain/ground/shield the no matter which pair could potentially touch in terminating and just providing the "0" reference point.

    Anywy back to concepts, there is a lot of single pair DMX grade cable on the market - ask your supplier for it specifically in that the only difference will be one pair instead of two pair.

    Also a side note of grade of cable recently done. Instead of black & white (white goes to pin two, black goes to pin three), most digital and DMX grade cable these days is using blue and white conductors. White still goes to pin 2. Blue and white conductors is also a sign that this cable is digital grade of a good impediance.

    Never but never use two pair cable with a XLR-3Pin Plugs or you will get Gremlens in your system. Don't matter if the manufacturer is supplying a two pair cable but of only two colors white/blue and connecting two wires per terminal or providing a two pair cable white/blue/green/red etc. Avoid them if possible even if the best on the market (my opinion in advise).

    Want this cable to work or fail properly as single conductor and never want a cable that tests fine dependant on how you hold it or shake it, but in a show going up situation might just have a say blue conductor of dual blue conductors that came undone. This in one testing situation in dual wires feeding the outlet might just test fine but plugged into the fixture not work properly in "gremlens in your system." All it takes is if two wires soldered to break and one connector to be not connected and it at the moment in being a duplicate data line be connected in testing, but that second wire now free floating now touching another terminal be it drain or white. Definate troubleshooting problems within a system should you have a free floater no matter what the color.

    That said you also never want a true DMX cable wired for three pin in conductors cut back at best or not connected to something. Such not connected conductors even if cut back still tend to travel within the cable and cause pandimonium in your system for troubleshooting. A not connected conductor within a cable or pair of them will do its best to travel within a cable so as to short in time in some way by way of the Gremlen in the system concept. Just avoid such cables. Unconnected wires travel within a jacket and cause problems often hard to detect the cause of.

    Cat.5 cables in much an above similar way won't persay if cut conductors connected to RJ-45 plugs but could potentially if to XLT over time. This in addition to the solid verses stranded issue in solid wire flexed/moved won't last as long. Sure for Cat5E cable it's about the twisting of the wire that by way of it shields it from electrical shielding issues and often cheaper, unless stranded and more difficult to terminate, Cat.5 cable often if in constant use is not an option for doing DMX. Some good stage rated Cat.5 cable out there that is is a bit more difficult to terminate but still have to worry if portable about the not used conductors say touching something they should not with time if used and moved about.

    Overall, as a single pair cable it if better grade it will probably have a drain wire outside of a foil shileld and blue and white conductors. That's good stuff and norm these days in that I don't think I have seen a single pair cable with drain, foil shield and tinned braided shield wire yet. TMB might have such a thing perhaps. (Not so fair with them last time with Soco plugs also in citing them now as best of two grades debatably between lots of other more standard DMX cable on the market - single pair or dual pair.) ProCable from TMB is the best on the market no question even if that dual wire pairs for the XLR and outer jacket melts easily. Their other grade also is at least standard for the industry normal.

    Overall concept, want the ProCable to last forever, don't let it touch a hot light or nobody installing it will use it once melted down even if "it still works though." This however with the true DMX ProCable in that the "single pair" cable from them has dual conductors which as above has been shown to cause problems if dual wire. Worst ever for me was a brand not Electronic Theater Controls but with blue markings and "ETC" on it that was dual pair and they wired the good quality cable for us as per single pair. Unfortunately they just kind of left the second pair of wire within the plug kind of at cut length just flopping about within the plug... Hmm, extra full length second pair of conductors just kind of flopping about within a plug, that's a good idea. Years later in bulk buy such cables still show up in the repair pile when found, not having been fixed or once fixed in being cut back a problem again unless made into true five pin.

    Worse than that above "Gremlen in the system" was a huge bulk buy with a very short time line for the cable needed for a show. Their own cable, their own empoyees making the cable "We can do this" on a short deadline, they had secretarys soldering cable. Endless bulk order on a short timeline that got made with constant Gremlens that still come up years later. Short timeline to get it done, "we can do this" and a tale of years of finding the flaws. Iron too hot and melting stuff, drain wire not insulated etc. Done deal.

    Inspect your cable on delivery. Also a question on buying in use of 22ga, 20ga or 24ga wire for use as best.

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