Getting rid of ground hum from stage lights

[giantslayer]

At my church, we have a nasty ground hum that is in all the mains, the monitors, and especially in the keyboards. We have some lights plugged in on stage (using two outlets). Those lights are hooked into a dimmer console in a back room. Last night, I unplugged them during practice so I could use those outlets for my guitar gear. All our hum everywhere instantly disappeared.

How do I go about getting rid of the hum (other than unplugging the lights)? I was thinking we needed to get some ebtech hum eliminators and plug everything through those. We have one of the monitors on one of those plugs that removes the ground and it has no hum. I'm a little uneasy about doing that with everything onstage.

I also noticed that ebtech makes one that connects to the power, instead of the signal. Would plugging the lights into those fix the hum problems? If so, that would be cheaper and easier than plugging all our monitors, mains, and keyboards through hum eliminators.

[cacibi]

Ideally - for any actively used stage - lighting should be on completely separate circuits than audio. The best long-term solution is to install new, dedicated audio power for the stage.

[ChurchPlayer]

What he said. And the dimmers will make you nuts too as I suspect the more they're dimmed the louder the hum. Other workarounds may or may not work, so if you buy anything make sure it's returnable or usable elsewhere.

[giantslayer]

I've shot a few emails back and forth with the guy from ebtech. Plugging the lights into hum x units (the ones that connect at the power supply rather than the signal) won't help. Plugging all the amps and such into hum x's would work. Last email I sent I asked him about using the 1/4" line level hum eliminators, to see if that would work.

[klasaine]

Originally Posted by giantslayer

I've shot a few emails back and forth with the guy from ebtech. Plugging the lights into hum x units (the ones that connect at the power supply rather than the signal) won't help. Plugging all the amps and such into hum x's would work. Last email I sent I asked him about using the 1/4" line level hum eliminators, to see if that would work.

Sometimes yes, sometimes no. I have a 'hum X'. Sometimes it fixes things sometimes it doesn't. Unfortunately in your situation, which is very common, the hum X rarely ever fixes anything. Try to find a musician that has one and borrow it.

[GoldieLocks]

I'm just curious if you tried using really long extension chords to get power from another part of the building? I'm not even sure if this would work. Let me know if you tried it?

[hotraman]

I had to chase down hums in our new church auditorium as well.
I, too, tried Hum X eliminators, Monster power conditioners, as well.
You will need to have a electrician take a look at it.
Poor dimmers will be amplified by guitars, keys and laptops.
Sometimes they just "appear" on their own.
After much work, we were able to git rid of 95% of hum... not to mention there are a few different types of "hums"

[giantslayer]

Well, it sounds like I would need to plug all the amps and probably the EQ's into hum-x's or something like that. We've got 3 amps, 4 EQ's, and 6 powered mains that would need to be treated. That's a lot at $60 a pop for hum-x's. There's got to be a better way to do this.

[ChurchPlayer]

We went through these headaches and to be honest the only "better way to do it" is to do it right. Get the lights on a separate circuit. If you can't do that then learn to do without the lights - at least until you can figure out somewhere else to put 'em. It's a royal pain, but speaking from experience if you fix the symptoms without fixing the problem then there's a good chance the gremlins will pop up again at the most inopportune of times.

[giantslayer]

I should get a long extension cord and see if there are any other plugs that are separate.

[hotraman]

Originally Posted by giantslayer

I should get a long extension cord and see if there are any other plugs that are separate.

That's the 1st place to start.
Don't get discouraged ( I may have wrote this already)
My problem with hums, is that they wouldn't be there at Thursday night rehearsals, and then "appear" in the middle of Sunday morning worship.
Can we say " spiritual attacks?"

[giantslayer]

I found out that the extension cord thing won't work. I don't remember the specifics, but the lights need to be plugged in there for some electrical reason. The confusing thing is, I tried unplugging them again to see if that got rid of the noise, and it didn't this time. It did several days ago, but today it didn't.

[dynocaster]

Originally Posted by ChurchPlayer

We went through these headaches and to be honest the only "better way to do it" is to do it right. Get the lights on a separate circuit. If you can't do that then learn to do without the lights - at least until you can figure out somewhere else to put 'em. It's a royal pain, but speaking from experience if you fix the symptoms without fixing the problem then there's a good chance the gremlins will pop up again at the most inopportune of times.

We had the same problem, but rectified it the same way.When we expanded our stage, we isolated a couple of double gang outlets for the amps. If you have a handy man in the church and a couple of free breakers it would be worth the trouble.

[giantslayer]

A quick update - we haven't done anything to fix the ground. One thing I did figure out is that the noise on the keyboards was coming from the XLR ground connection to the board. This was fixed by getting a halfway decent direct box and lifting the ground on it. (By the way, cheap direct boxes suck. They make things noisier and the ground lifts don't help anything.)

The hum from the keyboards was 80% of our noise problem, so with that fixed the hum on the mains is low enough to not be a distraction.

[scooteraz]

Originally Posted by ChurchPlayer

...I suspect the more they're dimmed the louder the hum...

Absolutely true. They have to dissipate more energy when the lights are dim (as the lights dissipate less). So, dimmers have some tendancy to "sing" when "dim" (not unlike people in a bar on Karaoke night...now that I have seen the double entendre of my statement). This is particularly true if they are designed for "up to 6 lights" and someone puts 10-12 lights on them (not that something like that ever happens)

[PraiseCaster]

Fuhrmann and Monster Cables make some power filter blocks that you can plug your amps/effects into and they have a loyal following. I also think that VooDoo Labs makes something similar.

Also, single coil pups will suffer more with dirty power hum/noise than humbuckers will, at least in my experience.

[PraiseCaster]

Another idea is, if you can get a small UPS System (Un-interupted Power Supply: Battery back up), that will filter all your power, and clean it up nicely.