Some interesting (to me at least) and hopefully useful info on why dimmers make noise

For help with setups and other technical issues.
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Bradley-Jazz
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Some interesting (to me at least) and hopefully useful info on why dimmers make noise

Post by Bradley-Jazz » Mon Sep 28, 2020 1:03 am

Hi All

My brother is fairly new to guitar playing (I am not), and last week got a nice new CIJ Hybrid Strat, which is his first electric guitar with single coil pickups. Last night I got a worried text from him that he'd changed strings and now there was terrible noise when he took his hands off the strings (sound familiar?).

My brother is an industrial electrical engineer (designs electrical systems for chemical refineries and power stations!), so whilst he knew fairly little about how electric guitars might behave, he understands far better than me electrics and electronics.

I explained that almost certainly the string change was a coincidence, and what he was hearing was EM interference picked up by his body being "heard" by the single coils, and gave him the list of usual suspects. Five minutes later he texted back that he had tracked the noise down to one of the dimmer switches in his house, the other one apparently having little effect.

He went away and did more research and this morning he texted me with the info below - might be of interest, and might help some of us with dimmers reduce the problem....
I’ve read up on dimmer switches, they work by the pot giving a control level to a triac which then turns the wave form on and off, so it’s not a reduction in voltage or current, it’s on and off very quickly the amount of time between the on and off giving the different lighting levels. So no wonder they chuck out so much crap, it’s a very crude rectifier.

Industrial equivalents were outlawed by EU directives about 20-30 Yrs ago due to EMC problems. Which is why I’d not really seen this problem elsewhere.

Seems that the reason that one dimmer circuit is ok and the other not in our dining room is because one is on the overhead led’s and the other is on filament bulbs on the wall lights... the LEDs aren’t a problem as lower current so less interference.

Solution is to replace the old bulbs with leds.

The better technical solution is to use dimmers based on autotransformers instead of triacs, but they’ll be bloody expensive. So aiming for lower current options is most practical, as the varying magnetic fields, which are causing the pickups to buzz, are proportional to the current flowing. So this doesn’t get rid of the problem, but does reduce it such as much less noticeable
Stop me if you think you've heard this one before....

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Veitchy
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Re: Some interesting (to me at least) and hopefully useful info on why dimmers make noise

Post by Veitchy » Mon Sep 28, 2020 4:02 pm

As someone moving into a house with dimmers soon, this is some good data.

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blunderbuss
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Re: Some interesting (to me at least) and hopefully useful info on why dimmers make noise

Post by blunderbuss » Mon Sep 28, 2020 9:53 pm

Right? Another reason to use LEDs.
Ryan

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JVG
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Re: Some interesting (to me at least) and hopefully useful info on why dimmers make noise

Post by JVG » Tue Sep 29, 2020 3:26 pm

That's really good info, thanks. Nice to have a professional looking at the problem objectively, rather than a bunch of ‘guitar guys’ speculating.

Please thank your brother for contributing (perhaps unintentionally!) to OSG.

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Bradley-Jazz
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Re: Some interesting (to me at least) and hopefully useful info on why dimmers make noise

Post by Bradley-Jazz » Thu Oct 01, 2020 1:02 am

Thanks - yes as soon as he sent me all that by text I told him, "that's going on OSG!"
Stop me if you think you've heard this one before....

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Re: Some interesting (to me at least) and hopefully useful info on why dimmers make noise

Post by timtam » Thu Oct 01, 2020 1:30 am

Would also be great to hear if switching the other dimmer(s) to LEDs does actually solve his noise problem.

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Bradley-Jazz
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Re: Some interesting (to me at least) and hopefully useful info on why dimmers make noise

Post by Bradley-Jazz » Thu Oct 01, 2020 1:41 am

I will report back after I speak to him next!
Stop me if you think you've heard this one before....

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Re: Some interesting (to me at least) and hopefully useful info on why dimmers make noise

Post by Scout » Thu Oct 01, 2020 3:37 am

Triac dimmers are resistive dimmers, they generally don’t see LED lamps, they were designed for incandescent and halogen lamps which are resistive filament lamps . There are volumes of technical details about dimmers, the older ones are not usually compatible with LED lamps. At this point all of your light fixtures should have LED bulbs, they use a small fraction of the power and last potentially forever, relatively speaking. To match the color of incandescent lights use should look on the packaging for the temperature rating of the color, you want one in the range of 2700K to 3500K which is degrees Kelvin. The higher the temperature the more into the blue/white spectrum, lower is the yellow/ red range. You made need to replace your dimmer if there is one to be compatible but it’s a small price to pay in the long run.

This is the talk I have with all my customers to convince them that LED lamps are the way to go, they truly are.

Not all LED lamps are dimmable, read the packaging if you want to dim them

You generally don’t want LED lamps in the 4000K to 6000K range, they have a harsh bluish light .

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Re: Some interesting (to me at least) and hopefully useful info on why dimmers make noise

Post by ogpuprison » Thu Oct 29, 2020 3:34 pm

problems involving dimmer units in places causing mash-ups in the audio have been around for decades. I look at it (as an audio install engineer) as it's about the complete electrical system in that property, I used to install hearing loops and the audio craziness ( in the PA system as well) when fire alarms or dimmers or magnetic local forces where around caused no end of hassles. But that's off topic. Unless your brother lives next door to a 30m mobile repeater or something

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Re: Some interesting (to me at least) and hopefully useful info on why dimmers make noise

Post by hexes » Sat Nov 14, 2020 10:12 am

blunderbuss wrote:
Mon Sep 28, 2020 9:53 pm
Right? Another reason to use LEDs.
to me, the light they give off is absolutely horrible (nothing to do with color temperature), and most every one I've tried in the US that claims to dim doesn't dim well (including different behavior with different dimmers) echoing what scout said above re:triacs. I've stockpiled incandescents like amp guys stockpile NOS tubes. I use LED in the kitchen and bathroom, but nowhere I plan on being for more than a few minutes.

that said, the dimmers (all incandescent lamps) in my house don't cause much issue at all with my guitars. the ones at work in our audio and video booths cause all sorts of gnarly buzz (professional performance hall).

if you are lucky enough to have sine wave dimmers in a facility (modern professional lighting systems), they don't cause much noise at all. I've worked audio in old theatres where once the lights dimmed down low, all the guitars and some amps would just buzz like crazy.

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