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I am running 3 Matrix 4 channel dimmer packs and 8 P64 LEDs. Everything is connected with install wire in the walls and attic with pockets to connect with each fixture. When I connect just the LEDs its fine. When I connect just the dimmer packs, its fine. However when I connect the whole chain it goes haywire. Yes using terminator.

Any thoughts?

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I could be wrong, but I don't think cable is the issue if things work when even the long run is with the LEDs by themselves they work fine.

The run goes about 35 feet back into closet out of the wall into all three packs, back into the wall, 45 feet to the front of the room, in and out of the celieing, down the wall and back out to 4 fixtures on the ground. Total run, ~175 feet
for DMX runs over 100 feet it is always recommended to use a opto branch 4.
Using one of these will help ensure strong signal across long dmx runs like you have. ESPECIALLY if you are not using all dmx cables. The way these interfaces work is by USB Power, and USb power while strong enough to output dmx is not gonna keep the same strength as a console plugged into a 120 volt wall outlet. I'm sure chris or serra ava will be happy to elaborate on this for you.
Let me go over my situation over the weekend, in which 8 64 LED Pro's kicked ass, ran fantastic and the bands ALL loved them. Rn by MyDMX, by the way.

Circuit A: 2 KV2 Audio EPack 2500's with an S 1.0 top and an ES 2.5 bottom. 500-watt PA, rang great. Basket-ball/high school gym shaped/sized room. Way too much power.

Circuit 2: 5 Mackie SRM450's(first versions, Italian made), 1 Mackie SRS1500A sub. These were monitors.
Band backline, 2 guitar amps(100-watts each). 250-watt bass rig. One bad brought in 4 Par56's and ran those too.
My 8 64 LED Pros also ran off this circuit.
No problems. NO PROBLEMS with any gear.

DMX signal chain:
MacBook Pro running Bootcamp 2.1, XP Home SP3 on PC boot. 3-foot DMX cable to:
Elation OptiBranch/4 splitter.
200-foot DMX cable to stage. 10-foot cable to first light. 3 3-foot cables between the 4 lights in the first tree. Out of fixture 4 in tree 1 is 50 feet of DMX cable, then 3 3-foot cables between fixtures and a DMX terminator.

I made the DMX terminated. All cable is Accucable. 2oo-foot run ran along side my 200-foot whip(56 channel audio cable), 200-foot CAT5 for AVIOM system, 100-foot power cable from FOH(on another circuit) and 100-foot CAT5 for video.

Again, let me repeat:
No problem.

I suspect a bad circuit, a motor on the circuit, or even too much draw on the circuit.

Might be other issues. If they are flickering, perhaps do you have them in a strobe mode? Is your DMX configuration on the lights correct? Have you tried to isolate it down to 1 fixture?

You're not plugging the 64 LED's into the dimmers, are you?

Start looking for your bad cable and check the status of the terminator and ensure it is not problem. Also, keep your DMX cable away from power cabling as much as possible, crossing at right angles only when absolutely necessary.
Based on the fact that when I attempt to run just the dimmer packs or just the LEDs everything is great, I went ahead and ordered a splitter (in route) and I am going to try that.

I should not have cheaped out on the cable, but with everything else for our church build out of a commercial storefront I was under a lot of pressure to go as cheap as I could.

The isolation should certainly help by keeping the dimmer packs of the signal heading to the front of the room. We even had a guitar DI'd, but the flickering was setting off his pedal setup.

Thanks for the thoughts. I spent about 5 hours on this Sat and tried anything I could, so I will see if the box helps.
Dimmer flicker is a tell tale sign of signal lose/degradation. My boss once used a 25' mic cable into a dimmer pack and then a 100' to another on the other side of the room. The first pack was fine, the second would flicker. This is of course after the arguments over and over again about how DMX and Mic cable is different. He learned the hard way. Now he doesn't question me specing 3 pin and 5 pin DMX as well as many splitters as I see fit/need.

I can tell you in the example above, I put a splitter after the first dimmer pack in line and the other dimmer pack worked fine. It was able to boost the signal enough to get it through 100' mic cable with no problems. However, I must stress that proper cabling is key. I have no doubt in my mind that if I had another fixture/pack chained after the 2nd dimmer pack, it would have had issues as well.

Also keep in mind that the more you add to your chain, the more it saps DMX signal strength. This is most likely the reason for one or the other working, but not both combined. Some toys also don't play nicely with others, and the splitter will all you to break them up, solving problems and quite possibly cabling as well.

As for the signal strength issues with dongles. It is basic electric physics. The chain is in series, however the fixtures are in parallel. Being in parallel, each one receives the same voltage, but different amperage which is where the signal comes from. Voltage is like pressure in a hose and the amperage is the water. No pressure, no movement of the water aka amperage. Now the reason it gets weaker over distance is do to cable and connection resistance. That is in series. Things in series receive the same amperage, but different voltage. So you have your water, but not enough pressure to move the water. Since dongles put out less voltage then consoles, the chain can only be so long and/or have so many fixtures on it.
Going cheap on the cable is somethng that may not appear ot be an obvious problem. I ran DMX for years on XLR cabling and it worked fine(even a 200-foot run), but that's not going to cut it for me anymore.

DMX cabling isn't that much more expensive than XLR cabling, with costs being in the DOLLARS for large-ish orders(say, around 300-feet of cable, less than $5 price difference on average in my experience and that price difference can swing either way).

Ordering a splitter is going to help but won't resolve your issues if you're NOT willing to buy the right cabling. It may help, but if you're willing to spend money on a splitter, why the hell aren't you willing to spend money on proper cabling?

It's like "Gee, I'm gonna get a super fast router and switch, I'm gonna spend $5 million on my corporate networking hardware infrastructure and we're gonna keep the same old Cat3 wiring that sucks for our phone lines and existing network instead of upgrading our cable plant as well" sort of idea that you're doing.

Then again, I have clients who will spend money to "Do it cheap" and then spend 10 times on the same issue to "get it done right" in the first place, instead of spending an additonal 5-20% in the first place to get the right stuff in the first place.

Plus, since you're investing in a splitter, and you've already ordered it, my advise is for nothing. The OptiBranch/4 has the additional advantage of not only being a splitter, but a 3 to 5 wire converter AND an optical isolator, thus ensuring problems in any branch shouldn't affect the the other brances, as well as making sure problems don't feedback down the line to your dongle, thus protecting your equipment and investment.

Sorry, but forgive my negative association with churches. Here, they've become business and they are tax evasion institutions. If churches are being bought and sold, going under and the like, trust me, this is about MONEY, ESPECIALLY when they are making churches from spaces formerly used as commercial storefronts. Couple that with bible thumpers roaming my neighborhood and ringing doorbells ar 7AM when I'm trying to sleep after pulling a 48-96 hour run of work. And they get all p*ssy when I have a weapon with me I am ready to use upon their person.

Here's the bottom line:
If you do it right, it may cost more short term, but costs less long term, and in some cases, long term savings can show up within 3 months. Have those over you chew on that a while. It's for the benefit of all involved to do it right.

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