EL Wire Driver Interference

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dragonfly Jafe
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Post by dragonfly Jafe » Tue Sep 14, 2010 11:29 am

try an RF choke?
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junglesmacks
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Post by junglesmacks » Tue Sep 14, 2010 4:08 pm

I'm thinking that the guys at Cool Neon would be pretty knowledgeable about this.. have you tried asking them?

http://www.coolneon.com/index.html
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uski
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Post by uski » Fri Sep 17, 2010 8:14 pm

I can help you but I need to know :
1) What was the power consumption of the inverters ?
2) What was the approximate frequency of the noise ? (very approximately! 200, 500, 1000, 2000 Hz...)
3) Are you sure the inverters you were using were designed to drive the length of EL wire you were using ?

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Token
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Post by Token » Fri Sep 17, 2010 9:38 pm

The problem lies with cheap drivers. The sad truth is that you are unlikely to find anything out there but the cheap stuff.

El Wire runs on AC 110V 1-4kHz. We are really good at hearing those frequencies.

The noise comes from the little transformers in the driver. It is a mechanical effect of the thin iron plates of the cheap transformer vibrating. Shielding with foil won't help.

Unless you are willing to build your own driver with quality components (lots of schematics available on the net), best bet is to put all the drivers in a sealed padded box with small holes for the leads.

Good Luck.

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gyre
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Post by gyre » Sat Sep 18, 2010 1:47 am

Lead foil is available.
Sheet is harder to find.

Dandy for acoustic isolation.

Mu metal is good for shielding, available as foil.

bud buddah
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Post by bud buddah » Wed Sep 29, 2010 2:59 pm

This is totally out of left field, but it might work if you can actually open the driver and see the transformer. If it really is just physical vibrations (which makes sense) could you dip the whole thing in some elastic coating, to hold things in place. I'm thinking of that stuff you use to dip tool handles in. It might be a whole lot easier than building one from scratch.
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Post by bud buddah » Wed Sep 29, 2010 3:00 pm

This is totally out of left field, but it might work if you can actually open the driver and see the transformer. If it really is just physical vibrations (which makes sense) could you dip the whole thing in some elastic coating, to hold things in place. I'm thinking of that stuff you use to dip tool handles in. It might be a whole lot easier than building one from scratch.
Bud

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gyre
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Post by gyre » Wed Sep 29, 2010 3:30 pm

The term is conformal coating for the wire.

May help for noise.

I like the silicone spray.

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Token
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Post by Token » Wed Sep 29, 2010 11:17 pm

Colonel Monk wrote:
Thanks Token - I hadn't thought of doing my own since they are so cheep. But I suppose it wouldn't be that difficult. I do have some experience building my own kit amps and such.

What makes the biggest difference, the quality of the transformer?
It's real simple. Use a 555 timer to drive a transistor and a transformer with a current limiting resistor or somesuch. Might have to match impedance and deal with the capacitance in the wire.

Plenty simple schematics available.

How the heck you here the driver buzz over the Playa noise is a much more interesting question. :)

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Token
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Post by Token » Fri Oct 01, 2010 8:12 am

Doh! How did I miss that part!

If your sound system is picking it up it's a different problem from what I was writing about.

Shielding and fixing the driver may help a bit but the main culprit is the wire itself. Huge antennae they are and you can't very well wrap them in foil.

Possible solutions:

Switch to CCFLs. More light but are rigid and 24" max length.

Wrap elwire with hair-thin wire such that the gap on the winding is at 1/4 wavelength of the driving frequency. Ground this shielding wire. This is a labor heavy way to go so test it before you invest the time and effort.

Ground and shield the audio equipment and cables. Ground the generator as well.

Actually, do a test at home. Plug the audio gear into municipal power where you know the groud is good. Run the elwire and see if it picks up the buzz.

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Snow
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Post by Snow » Fri Oct 01, 2010 1:14 pm

sounds like your interference is electrical not audio. But I have heard this tip to get rid of the audio noise (which btw you can't hear really when on playa). Open up the driver and coat the transformer with hot glue. This gets rid of that annoying hum. I haven't tried this myself since I don't notice when on playa, but it can be maddening in other settings.
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tomasz
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Re: EL Wire Driver Interference

Post by tomasz » Sat Sep 01, 2012 11:15 pm

Hey guys,

I was hacking around tonight with my EL wires and noticed something very similar, but the difference is that the audio system that picked it up was my smartphone's hands-free headphones/microphone (the person on the line also heard it). What's more is that the sound got louder as I put my hands closer to the actual EL wires. Not sure what that means, but it suggests that it's actually the EM field around the wires that's causing the interference, and not just ground interference.

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gyre
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Re: EL Wire Driver Interference

Post by gyre » Sun Sep 02, 2012 12:06 am

The ballast is probably running at 110 vac or higher and 2-4kHz, according to one site.

So rf is a real possibility.

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