paulears Posted March 20, 2013 Share Posted March 20, 2013 X32 forum link Have a look at post 5483. Somebody complains that a spark from a loose connector can crash the desk - so somebody connects the mains to a file, and runs a nail along it to do the test - Nice sparks! Link to comment Share on other sites More sharing options...
GR1 Posted March 20, 2013 Share Posted March 20, 2013 I put it down to the strong vodka and dark winters... Link to comment Share on other sites More sharing options...
Dmills Posted March 20, 2013 Share Posted March 20, 2013 Back in high school I used something not a million miles from that to pull of a lightning effect for a show (Basta*d file, cinema projector carbon and a fair number of car batteries and jumper cables, ~60V OC as I recall and the current was enough that I had to strap cables together to stop them moving in the resulting fields), gave myself arc eye. Still safer then mains, definate case of "Hey guys watch THIS!" trying that! Regards, Dan. Link to comment Share on other sites More sharing options...
bigclive Posted March 20, 2013 Share Posted March 20, 2013 Not super-safe.... BUT, with the 1000W heater load it would have generated quite nasty electrical noise as desired. I'm sure there is a machine for generating similar interference, but I'll bet it costs more than an old heater and a file. Note that if attempting that stunt, even with an RCD breaker the most likely fault scenario is making contact with both bits of metal at once and that would neither trip the MCB or RCD, but would pass potentially fatal current through your body. So don't do it. Link to comment Share on other sites More sharing options...
Bobbsy Posted March 21, 2013 Share Posted March 21, 2013 ** laughs out loud **. I'm sure you can crash anything if you try hard enough. I've told this story before but, years ago, I was mixing a production of Return to the Forbidden Planet on my newly-purchased Yamaha DM1000. The director and the production designer decided that my FOH mix position should be an extension of the set and I was given a surround in basically the same design as the walls on the stage--and a plasma ball to stand in each corner zapping away. I have to admit it looked kinda neat! However, the discharge from the plasma balls did NOT get along with the DM1000 and the problem manifested itself with all sorts of strange things, including motorised faders deciding to move by themselves at random times. Channel 1 (which worked out to be closest to a plasma ball) eventually decided to sit there going up and down about half the range. Needless to say, the set decoration had to be revised! Anyway, just goes to show that, if you try hard enough, you can disrupt anything! Link to comment Share on other sites More sharing options...
bigclive Posted March 22, 2013 Share Posted March 22, 2013 Plasma balls are high voltage RF emitters. They will adversely affect most electronic equipment put near them, including the risk of causing damage to it. All the light you see is from a single electrode radiating as RF energy. That makes them quite a powerful transmitter. Neon signs are also a bit of a dog at times with regards to emitted fields. Especially the ones with electronic transformers. Link to comment Share on other sites More sharing options...
Dmills Posted March 22, 2013 Share Posted March 22, 2013 Fortunately most things of the plasma ball, tesla coil and like nature are actually fairly low frequency (Hundreds of Khz to maybe a few Mhz) as these things go, and are electrically small so they do not in fact radiate particularly well once you get out into the far field, this does not of course help in the near field.... Classic one I had was the a set that involved a pair of fairly large tesla coils (Outdoors, with suitable risk assessment), all fine until the vidiot (That I did not know about) swans in at final rehersal and starts giving me earache because his RADIO MIC was not working properly and he did not have suitable hardware to take a feed from sound. Someone got called a vidiot to his face. Regards, Dan. Link to comment Share on other sites More sharing options...
Stuart91 Posted March 22, 2013 Share Posted March 22, 2013 I'm sure there is a machine for generating similar interference, but I'll bet it costs more than an old heater and a file. Pat Brown of Synaudcon recommended using the power supply for an electric fence, with a short gap between the two terminals. With the correct size gap, you get an arc, with pretty powerful broadband interference. Link to comment Share on other sites More sharing options...
dbuckley Posted March 22, 2013 Share Posted March 22, 2013 I'm surprised that an eleccy fence is that good in this respect, they only have a very limited output power, even though it is at several thousand volts. The sparks are quite tiny. Link to comment Share on other sites More sharing options...
Stuart91 Posted March 25, 2013 Share Posted March 25, 2013 I'm surprised that an eleccy fence is that good in this respect, they only have a very limited output power, even though it is at several thousand volts. The sparks are quite tiny. He's based in Indiana in the US. Maybe they're using bigger supplies than are common over here? (It was an offhand comment he made in a seminar, I filed it away under "things to do on a rainy day") Link to comment Share on other sites More sharing options...
themadhippy Posted March 25, 2013 Share Posted March 25, 2013 several years ago I built a plasma tweeter,sounded nice ,looked pretty, however my neighbour wasnt so impressed with the interference it produced on there telly Link to comment Share on other sites More sharing options...
dbuckley Posted March 25, 2013 Share Posted March 25, 2013 I've seen reports of plasma tweeters, and that the ozone produced makes them incompatible with pleasant life... Link to comment Share on other sites More sharing options...
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