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Sound Reinforcement - Forums for Live Sound Professionals - Your Displayed Name Must Be Your Real Full Name To Post In The Live Sound Forums => AC Power and Grounding => Topic started by: Mike Sokol on December 06, 2017, 03:20:17 PM
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Nope, Neon Buzz is not the name of a retro group, but maybe it should be...
A former student of mine is now the A1 in a Wash DC club where they've installed a giant neon guitar pick sign on the back wall of the stage. Something like the neon heart in my picture, and maybe 6 feet tall. Yup it's a real neon sign with a step-up 120-volt to 50-Kvolt-ish transformer. This is a new club and they've discovered that any guitar that gets anywhere near this thing buzzes like crazy, especially ones with single-coil pickups. He's tried different grounding techniques including Ferrite cores on the transformer leads which didn't help. And he built a few 1/4" guitar cables with small shunting caps inside to try and short out the buzz, which helps a little but guitars players don't want to mess with their tone. I told him that this big sign 5 feet away from the guitars is basically a huge radio antenna, and that trying to ground the transformer is futile. However I suggested that perhaps someone makes a DC or ultrasonic neon power supply to make the 50KV or so needed, and that either going DC or 20KHz would move the interference out of the audible range.
Anyone here play with this sort of thing?
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Nope, Neon Buzz is not the name of a retro group, but maybe it should be...
A former student of mine is now the A1 in a Wash DC club where they've installed a giant neon guitar pick sign on the back wall of the stage. Something like the neon heart in my picture, and maybe 6 feet tall. Yup it's a real neon sign with a step-up 120-volt to 50-Kvolt-ish transformer. This is a new club and they've discovered that any guitar that gets anywhere near this thing buzzes like crazy, especially ones with single-coil pickups. He's tried different grounding techniques including Ferrite cores on the transformer leads which didn't help. And he built a few 1/4" guitar cables with small shunting caps inside to try and short out the buzz, which helps a little but guitars players don't want to mess with their tone. I told him that this big sign 5 feet away from the guitars is basically a huge radio antenna, and that trying to ground the transformer is futile. However I suggested that perhaps someone makes a DC or ultrasonic neon power supply to make the 50KV or so needed, and that either going DC or 20KHz would move the interference out of the audible range.
Anyone here play with this sort of thing?
I have a personal night club in my basement, and on the wall which is the longest distance, about 15 ft, from my demo/rehearsal studio room, I have not noticed any interference from a large - approx. 4 ft by 4 ft - neon sign.
This older sign was purchased near Cleveland in 2011. The original sign transformer was a dual secondary, "brute force", conventional transformer. That transformer failed about 10 hours after I began to use it.
I took the option to buy two hi frequency oscillator type neon supplies to replace the very big and heavy (expensive) original HV xfmr. The new ones work well. Not sure if the sign in question has that sort of supply or not...
Perhaps the new supplies, like mine, have integral AC line filters, but as you described - the radiation from the pick sign certainly would cause issues, especially with single coil pick ups. And apparently not AC line hash.
I have not tried a guitar near this sign, but all my guitars are hum buckers which could still be affected, perhaps not as much as single coil. I am sure they wish to keep the sign. It will be interesting to see how this develops on a solution.
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I have no idea if it would work, but how about a copper screen faraday cage for the sign and transformer. It would also have an advantage for those "Blues Brothers at the CW bar" moments.
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6 feet tall. Yup it's a real neon sign with a step-up 120-volt to 50-Kvolt-ish
6 ft high and 50 kV is a serious neon sign. I don't have any direct experience with this problem but RFI is generally better controlled at the source. Maybe some HV caps to round off the inductive voltage spikes that result each time the Geissler tube extinguishes (120 times a second). I look forward to learning the ultimate solution.
I did once build a Jacob's ladder using a neon sign transformer 8) -F
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This is the kind of stupid stuff I've come to expect in clubs. The silly decision to put a broadband RF noisemaker 6 feet behind the guitarists then becomes the audio depts job to "fix" when the solution would have been a different type of tube lighting, a different PSU for that lighting, or putting it somewhere else besides right behind the devices most likely to be affected.
Grrrr.
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This is the kind of stupid stuff I've come to expect in clubs. The silly decision to put a broadband RF noisemaker 6 feet behind the guitarists then becomes the audio depts job to "fix" when the solution would have been a different type of tube lighting, a different PSU for that lighting, or putting it somewhere else besides right behind the devices most likely to be affected.
Grrrr.
On the Broadway show "Passing Strange" the upstage wall was completely covered in 4' tubes that all lit up in the final number of act 1. The head electrician, the late Steve Cochran, spent at least 3 weeks replacing a few fixtures or ballasts every day trying to get them quiet enough to not interfere with the IEMs. He was a hero. I think he found hospital rated ballasts to be best.
Mac
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I can’t offer any technical advice, but in those shoes I’d go straight back to the sign manufacturer/supplier for a more suitable solution.
Before long bands won’t want to play the venue, and I doubt ticket sales have climbed substantially to see the “new sign”. I know tour managers who have blacklisted venues for what I would consider far less rational reasons than what you’ve described. It takes a whole lot of work to bring them back around again after the damage has been done.
/rant.
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On the Broadway show "Passing Strange" the upstage wall was completely covered in 4' tubes that all lit up in the final number of act 1. The head electrician, the late Steve Cochran, spent at least 3 weeks replacing a few fixtures or ballasts every day trying to get them quiet enough to not interfere with the IEMs. He was a hero. I think he found hospital rated ballasts to be best.
Mac
That's why Steve had the reputation he did - above and beyond - and he didn't make it your or Tommy Morse's problem to fix.
The basic solution would have been to use a different tube product, even back in 2007. "Designers" don't seem to collaborate before they create stuff that doesn't work or play well other stuff and then can gets kicked down to the crew.
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The basic solution would have been to use a different tube product, even back in 2007. "Designers" don't seem to collaborate before they create stuff that doesn't work or play well other stuff and then can gets kicked down to the crew.
If they would have asked me in advance, I would have suggested some sort of LED solution. Heck, for the amount of money they paid for a actual neon sign, they probably could have gotten a blown glass tube in the proper shape and strung a bunch of mini LED's inside of it. Retro-Cool with modern technology.
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I would worry about fragile glass with 50kv right behind me. Think mic stand topple. Yikes.
Sent from my iPad using Tapatalk Pro
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Obviously this was someone's brilliant vision in order to justify spending what they did.
Perhaps that person needs to be convinced that it would look "way cooler" behind the bar?
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Obviously this was someone's brilliant vision in order to justify spending what they did.
Perhaps that person needs to be convinced that it would look "way cooler" behind the bar?
Or somewhere it "can be seen". Once the band sets up it's obscured, ya know? ;)
They spent some serious coin on this and it would be nice if it "lived" somewhere it could be an attraction rather than a distraction - cool to promote live music, not so much to make some guitars unusable.
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Nope, Neon Buzz is not the name of a retro group, but maybe it should be...
A former student of mine is now the A1 in a Wash DC club where they've installed a giant neon guitar pick sign on the back wall of the stage. Something like the neon heart in my picture, and maybe 6 feet tall. Yup it's a real neon sign with a step-up 120-volt to 50-Kvolt-ish transformer. This is a new club and they've discovered that any guitar that gets anywhere near this thing buzzes like crazy, especially ones with single-coil pickups. He's tried different grounding techniques including Ferrite cores on the transformer leads which didn't help. And he built a few 1/4" guitar cables with small shunting caps inside to try and short out the buzz, which helps a little but guitars players don't want to mess with their tone. I told him that this big sign 5 feet away from the guitars is basically a huge radio antenna, and that trying to ground the transformer is futile. However I suggested that perhaps someone makes a DC or ultrasonic neon power supply to make the 50KV or so needed, and that either going DC or 20KHz would move the interference out of the audible range.
Anyone here play with this sort of thing?
I had exactly the same problem in a country bar some years back and it turned out, when I opened the transformer box, there was a poor connection and some small arcing.
Tightened all the connections and problem solved.
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If they would have asked me in advance, I would have suggested some sort of LED solution. Heck, for the amount of money they paid for a actual neon sign, they probably could have gotten a blown glass tube in the proper shape and strung a bunch of mini LED's inside of it. Retro-Cool with modern technology.
LEDs aren't always the solution. I had one venue with LED front lighting that would cause havoc with any single coil pickup devices. If the guitar player faced the lights, buzz. If he turned his back to the lights, it was fine. It wasn't a ground loop issue, as the buzz was still there even running wirelessly. The problem was mitigated to a slight degree by putting a steel screen in front of the LED lights. The LEDs were finally replaced, and now the problem has pretty much been eliminated. Totally crazy.