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Author Topic: Y cord at DMX board  (Read 1347 times)

Lyle Williams

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Re: Y cord at DMX board
« Reply #20 on: July 06, 2018, 05:02:35 pm »

The data rates in DMX are very low.  The physical length of bits on a wire are huge.

Sadly people run unterminated DMX all the time.  That is so much worse than a Y-split in the middle of a line terminated at both ends.  Put a cro on your DMX and have a look at those waveforms.

Dodgey is dodgey.  Don't plan on being dodgey.  Plan on being solid and robust, and if some technical gaffer tape needs to be applied, you may be ok.  Don't plan on operating a huge beachball of technical gaffer-tape on gaffer-tape on gaffer-tape.

But when crisis strikes (opto-splitter left in last town?) don't use learned helplessness masquerading as professionalism to fail to produce a solution that a noob would have got working.

A y-split is 1% less dodgey than letting the show fail.

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TJ (Tom) Cornish

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Re: Y cord at DMX board
« Reply #21 on: July 06, 2018, 06:27:27 pm »

The data rates in DMX are very low.  The physical length of bits on a wire are huge.

Sadly people run unterminated DMX all the time.  That is so much worse than a Y-split in the middle of a line terminated at both ends.  Put a cro on your DMX and have a look at those waveforms.

Dodgey is dodgey.  Don't plan on being dodgey.  Plan on being solid and robust, and if some technical gaffer tape needs to be applied, you may be ok.  Don't plan on operating a huge beachball of technical gaffer-tape on gaffer-tape on gaffer-tape.

But when crisis strikes (opto-splitter left in last town?) don't use learned helplessness masquerading as professionalism to fail to produce a solution that a noob would have got working.

A y-split is 1% less dodgey than letting the show fail.
A Y-cable with two unterminated ends is significantly worse than an unterminated single-ended transmission.

Not exactly sure what your point is - hopefully a successful show is worth a $100 opto-splitter to do it right the first time.
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Lyle Williams

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Re: Y cord at DMX board
« Reply #22 on: July 07, 2018, 04:28:44 pm »

Y-in-the-middle to two unterminated ends is worse.

My point was that "linear unterminated" was worse than "y-in-the-middle but terminated at bith ends".

Actually, that wasn't my key point.  My key point was don't plan on being dodgey, but understand that this whole endeavour is one big improv job.  The show must go on, and this issue isn't safety-related.
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Patrick Campbell

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Re: Y cord at DMX board
« Reply #24 on: July 23, 2018, 10:25:33 am »

With the new splitter and all DMX cables and a terminator at each "station"

The 4 way splitter/booster goes to four stations  Upstage Left/Upstage Right/ Downstage Right/Downstage Left

Each station has four slim par 64's and mover and then a terminator

Having no trouble at and that you everyone for the advice

Thanks again

Patrick
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Debbie Dunkley

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Re: Y cord at DMX board
« Reply #25 on: July 23, 2018, 10:40:41 am »

With the new splitter and all DMX cables and a terminator at each "station"

The 4 way splitter/booster goes to four stations  Upstage Left/Upstage Right/ Downstage Right/Downstage Left

Each station has four slim par 64's and mover and then a terminator

Having no trouble at and that you everyone for the advice

Thanks again

Patrick

I went to a DMX splitter a few years ago and it was a great move. The only lights I DMX daisy chain are the 4 on each lighting tree using 2ft-3ft cords. However each tripod has its own feed  and so does any other lighting I use on stage. I also only use good quality DMX cable and named brand XLR connectors. 
I like the fact that if a fixture or cable goes down on one branch of the system, nothing else is affected. This has saved me a couple of times.
Recently, as I posted here, I had some flickering occur on one or two of the lights on the 4 par bar whenever I had the lights too close to TV's -something I'd never heard of before - but it seemed to happen in 1 particular local venue and happened each time we played there.
I upgraded my cabling on the 2 front lighting sets and next visit to that venue -VOILA! No more issues.
So I think with lighting, a lot like sound, the system is dependent on its weakest link - the difference being that DMX will be far more obvious in letting you know there is something wrong.
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A young child says to his mother, "Mom, when I grow up I'm going to be a musician." She replies, "Well honey, you know you can't do both."

Steve Garris

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Re: Y cord at DMX board
« Reply #26 on: July 23, 2018, 01:35:59 pm »

I went to a DMX splitter a few years ago and it was a great move. The only lights I DMX daisy chain are the 4 on each lighting tree using 2ft-3ft cords. However each tripod has its own feed  and so does any other lighting I use on stage. I also only use good quality DMX cable and named brand XLR connectors. 
I like the fact that if a fixture or cable goes down on one branch of the system, nothing else is affected. This has saved me a couple of times.
Recently, as I posted here, I had some flickering occur on one or two of the lights on the 4 par bar whenever I had the lights too close to TV's -something I'd never heard of before - but it seemed to happen in 1 particular local venue and happened each time we played there.
I upgraded my cabling on the 2 front lighting sets and next visit to that venue -VOILA! No more issues.
So I think with lighting, a lot like sound, the system is dependent on its weakest link - the difference being that DMX will be far more obvious in letting you know there is something wrong.

Just curious, do you buy those DMX cables or make them? If purchased, where?
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Debbie Dunkley

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Re: Y cord at DMX board
« Reply #27 on: July 23, 2018, 02:05:29 pm »

Just curious, do you buy those DMX cables or make them? If purchased, where?
I made all the upgraded ones Steve. It seems the ones I purchased pre-made are the ones that let me down - I dont think they were great connectors. I did try some pre-made ones by CBGS first which work fine but in the end I made my own and I keep the CBGS as spares.
I already had the cable from way back when I first stated using DMX but never got around to making the cables myself so the upgrade was easy for me as I already had everything - I just needed to put the soldering time in. I don't remember spending a lot on the cable but I used all Switchcraft and Neutrik connectors.
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A young child says to his mother, "Mom, when I grow up I'm going to be a musician." She replies, "Well honey, you know you can't do both."

Patrick Campbell

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Re: Y cord at DMX board
« Reply #28 on: July 23, 2018, 02:15:42 pm »

ANY IDEA WHERE TO FIND  18 INCH DMX CABLES ?
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Jeff Lelko

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Re: Y cord at DMX board
« Reply #29 on: July 23, 2018, 04:02:20 pm »

ANY IDEA WHERE TO FIND  18 INCH DMX CABLES ?

Why not make one?
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