electrical interferance?

[cyrax037]

Interesting!


So are you saying that its not likely that its the E-field emanating from the light box effecting the speaker snake? Thats what it seemed like to me, that it was more to do with the field, then an issue in the power source. IDK tho.
(I forgot to mention that the board is now plugged into another electrical jack in another location upstairs, then it was before, and still has the problem.)


Here is a picture I thought might help.(its from my phone, so I apoogise for the quality)


This is the power box I was talking about, that sits behind my chair. The light box goes into that. I don't know if power runs through it to the lightbox, or if the power runs from the lightbox through it to the lights themselves.

[cyrax037]

I just found out tonight, that the board is indeed on a separate breaker then the light box, and still buzzes.

[mikeymo1741]

Is there any way you can kill power to the lights and keep the board/speakers powered. Maybe from a breaker/fuse before the power gets to that junction box?

[cyrax037]

Yep, sure is! We turn off all of the breakers in the back breaker box when we leave, to shut everything down.(well, everything is turned off first, but we kill power for safety) except for a few breakers in the front breaker box, and perhaps one or two in the back one, I'm not sure. With the normal stuff off, that plug the board is in now, apperantly is on a breaker we leave on. With the light box off, there isn't really any noise, except a hiss when I get the mics really hot, but if I turn the light box on, the buzz starts.(even when the switches are off, but there is power to the light box, there is only a hiss with the mics hot, but I start raiseing the light sliders up, and it starts.)

I will be there in just an hour or so, so I will test it again to get the details for sure on when there is NO power to the light box.

[mikeymo1741]

What does the lighting board look like?


Chances are it's a triac dimmer, which are known to cause interference. There is supposed to be circuitry in them to suppress it, which might be failing.

Sounds like you have two choices: move the audio wiring, or get an electrician to fix the lighting wiring.

[cyrax037]

Here is a couple pictures. I don't know what a "triac" dimmer means, but here are he best pics I have of it.





You can see pretty much my whole setup in the second one. The light box, with the yellow note on it. The board, the stacked audio players, bottom=tape deck, middle=6 disk changer(neither plunged in) and the CDG player! You can also see the light boxes cables underneath the desk in the blue tubing.

Fortunately, for now the buzz seems to only be when I get the gain and sliders up really far on the channels(with or without a mic, no difference) Unfortunately, some of the kids NEED to get those mics really hot to be able to hear them. I'm not entirely sure what pre-amps are, but I know we don't have them, or any other amps other then whats built into the board.

[mikeymo1741]

Wow, that's worse than I thought. Those look like basically consumer-grade sliding dimmers. Yuk. No wonder you have noise, right next to the mixer like that.

I think pretty much your choice is to move the mixer.

[cyrax037]

yuk, that doesn't sound like fun. That's probably not an option currently, maybe when things get remodeled. Funding is a major issue, practically ever dime we make goes into the restoration fund, which currently is set for the roof. We can run on the audio equipment we have, but we can't open, if the roof collapses, which I'm afraid is more and more likely every rainfall.

[cyrax037]

Ok, its been awhile since I've posted here, but I think I might have found what the problem is, dunno how to fix it yet, but this website tells what I belive the issue is.

Other noise sources

Pretty much like I had thought. The EMI issue, from the dimmer switch. I just dunno if its in the dimmer cables, or the box itself, or both. I didn't expect to read that encasing it in magnetic material would help, I would have though just the opposite. So, I dunno. My only option might be to wait till things are remolded, and hope it doesn't get worse.

Anyway, I wanted to share that link. Thought it might help others, here is the main one on ground loop issues that could be helpful aswell!
Ground loop problems and how to get rid of them