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Ok New to here...So first off hello to everybody..Ok I have a issue..I have 2 scan250's
running together in master and slave mode.Ran
off of a light controller just for on and off..
Recently when the kicked on heard a "Buzz" just a quick noise through the speaker system Almost like a electrical draw is the best way I can describe it..Throught out the nite this keep recurring..The next gig never happened all night..The last gig It started doing it again and then seemed to quit..No common factor inbetween anything...We confirmed it was them by shuting them off and the sound never happened again.turned them back on it started happeneing
again not a constant noise just every 5 min or so..Any help?????

Thanks in advance..
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It could be a grounding issue. If the PA and the lights are on the same circuit, you could be in a ground loop, which will certainly cause a buzzing. Since it comes and goes though, it sounds as if the loop may be a short/intermittent connection somewhere.

Normally, I'd recommend lifting the ground in most cases, but on intelligent lights, I really don't recommend it. You could possibly lift the ground on the PA if it is on the same circuit as the lights (it's up to you though, because there is always some risk in lifting the ground, but it usually solves ground-loop issues).

Just some ideas, not sure if it will help. Just be careful and think things through.

You'll want to find a product that will use a transformer to lift the ground rather than those 2/3 prong plug adaptors.

In my rig, I don't lift grounds. Period. I do have individual ground lifts per channel on all my inputs and outputs on my 56-channel snake, and my monitor routing is ground isolated and run down a Cat5e cable.

A company that starts with the letter E and ends with Tech and has a "b" right after the first E makes a fairly good line of products that should be able to address this issue.

I think you might also check to see where your DMX controller is plugged into. Is it on the same cirucit as your main mix position? Is your PA in the same cirucit? If so, your DMX cable is facilitating the ground issue. If it was an XLR, I'd recommend removing the connection from shell to shell and sever 1 at the male end. However, I don't like removing the shield connection on Pin 1 and all my cables are standardized. I forget what pin is what in a 3-wire DMX, but you can remove your ground since all they are really using is async TX and RX anyways at a fixed DTE, nothing major. Still, I try to not lift ground in data cables either.

I'm not using any intels or movers yet, so I can't comment further. But definately "divide and conquer". You need to discover the true source of the problem. I personally have not had any issues yet.

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