So I was changing a lightbulb last night…

Your body is acting like an antenna, when you touch the fixture you help the EMI/RFI radiate further than it would otherwise.

The system and you are interactive.

Interesting, thanks!

Great demo video of the phenomenon. Check the grounding of your light fitting.

@durte30-

I would first bypass the dimmer completely and check to see if the issue remains. I’m not familiar with the type of LED fixtures you are using but there could be the possibility of noise if a frequency inverter is involved. I’d start with the dimmer-

Time to get a battery powered TT light. 

@designsfx They are just normal fixtures. I switched out all the lights in my house for LED’s to save electricity but all of the lights in the basement would flicker when dimmed so I bought a dimmer specifically for LED’s and no more flickering after I wired that in. If this was really impacting my listening experience at all I’d probably pull the dimmer out and wire in a normal switch but I usually have the ceiling lights off when listening anyways and have a couple lamps on instead. So I’m not really looking for a solution I just thought it was interesting and that I’d share it here! Was also curious what was happening. 
 

@russ69 sounds like a business opportunity, ha!

I have all LED lights in my home and an LED turntable light and no real RFI/EMI issues. Also I have dedicated circuits. Interesting though, will keep an ear open for this.

@Durte30 There are 'dimmable' LED bulbs and 'dimmable' LED dimmer switches.

I have had many buzz, even one light out of a box of 'dimmable'.  Go ahead and waste some money and try an incandescent bulb..and let us  know!  Cheers to you as well!

Pretty interesting.

I am assuming it is the electrical field.
 

1. Is the tone arm grounded to anything?
2. Do you know if the lights and the gear are on the same side of the 110v that makes up a 220v pair?

+1 for it likely being the dimmer switch...

@holmz The tonearm is grounded to the back of the phono stage. As for the light circuit and audio circuit being on the same side, I’m not sure. I’ll take a look later and report back!

Don't touch the light fixture when you're playing music at full volume.

    +1 @erik_squires , I had to laugh as it reminded me of my childhood days when dad said “ Hold the TV antenna “. EMI, capacitance, and electrical conduction all come into play when we place our body in the circuit. I’ve removed dimmer switches, flouresent lights and added additional grounding and shielding as I’ve progressed with my modest system. Battery powered lights and fans are a plus too, as already mentioned. I’ve gone so far as to try late night listening and turning off most of the breakers on my panel to seek noise reduction. Happy Listening, Mike B. 

+2 to the dimmer causing the buzz.

LED bulbs can have noisy DC power supplies, dimmers have also seemed to cause noise

Your stereo is not on a totally isolated ground ,like myself  I had a dual insulated isolated  dedicated ground.

It's just your magnetic personality....but I'd stay indoors during lightning storms. ;)

I had a mystery *hum* awhile back, sharing an input between my office and main systems.  Turned out to be a grounding issue, but it made me crazy(er) for awhile.

There's always a nice scented candle or two....adds to the atmosphere....*G*

Still hoping to find someone explaining the effect. Why is touching the ground (lamp body is normally grounded) with a human body (fairly well insulated from ground, assuming shoes, ladder, carpet) getting a signal to the tone arm. Since foil around the arm stops it, appears 'wireless' (EMI). 

If EMI (and only when dimmer switch on; does it change with dimmer in FULL ON or LOW?), the dimmer must 'load up' EMI onto the housing of the lamp that the body then picks up, magnifies and sends to the tone arm. 

My guess would be the dimmer is the culprit & usually worse when they’re dimmed way down. Cheaper ones can even “sing” themselves. Try it both fully dimmed & fully open. Can also try replacing the dimmer w/ a better quality, higher wattage one or simply a regular switch. 

You discovered for YOURSELF one of the OLDEST sore spots for the Phonograph, the Cart and it's associated wiring are the WORST for picking up spurious signals. they are the BEST antennas for radio frequency signals ever invented. Though you might find some success looking at  the things that are mentioned by the other people here, and they are not wrong in looking for the source of the radio signal, your real problem is the Cart. while these other people are spending all of their time looking for the source of the signal, yes, they are looking for sources of radio freq signals BUT, without you touching the lamp, thus creating an antenna, you wouldn't have the problem. Those offending source signals are whiteout harm or offense without YOU as the transmitting antenna. They can not propagate a signal W/O an antenna.

The hum at 60Hz coincidentally creates a pleasing even-ordered harmonic when played in conjunction with the first cut of Pink Floyd's Dark Side of the Moon album.

Make lemonade out of lemons?

Grounding issue, as has been mentioned. I suggest you have two options.

1) You can hunt down why that light fixture isn't grounded properly. When you're touching it, your body is providing the ground. Luckily for you, you didn't get jolted.

2) Use something else for a TT light. I use one of these:

Works well and is unobtrusive. And of course, I leave it off when listening.

Good luck and ... Happy listening.

I loved buellrider97’s quote of “ Hold the TV antenna “.

I remember hearing that as a kid. I’d just touch the big metal tv channel selector know and the picture got better. My dad and older brothers would tell me to just stay right there! Don’t move!

Yes there is an effect/interaction with your body when you touch it. Also dimmer switches are notorious for causing hum, incandescent or LED. I’m having a very slight buzz with mine also. The LED track lights I first purchased weren’t dimmable so I went back those very small incandescent track lights which are controlled by a remote control dimmer switch. Works great and looks wonderful shunning down on the stereo system and speakers. I didn’t really notice the buzz until I was checking a different issue one night and turned the volume way up. I started checking for the buzz now and turned the lights up to look around. Of course as I turned the lights up the buzz changed and when the lights were on full the buzz was barely there. Turned the dimmer coming off and the buzz disappeared.

I have my entire stereo system on two separate 20 amp breakers which are independent from the lights. I also have a 20 amp balanced AC isolation transformer (Equi=Tech) which means the AC is 60-0-60 powering everything except my computer server. That is on one of the 20 amp lines going through a battery backup/regulated AC supply, then through a high end isolation transformer, then to the regulated 12V power supply with a very large bank of capacitors and up to the server. This also is USB isolated with an iFi galvanized power supply to my DAC.

So all this care and the buzz from the dimmer still comes through. Barely but it just shows the issue with dimmer switches. The only thing I can think of (if we want to keep some sort of AC dimming) is to research some sort of AC filtering that can be added right at the dimmer control. Ether a very small isolation transformer or EMI/RFI filtering system that would knock this out. It would have to be right in line with the switch so nothing from the switch or lights can feed back into the AC line.

@jonwolfpell you’re right, the buzzing was worse with the dimmer all the way down.  Maybe I’ll get a regular switch after all.

@musicfan2349 any advice on how to make sure the fixtures are grounded?

This has reminded me that I used to have a musician roommate in the room directly above this and he would always turn the lights off in the basement when he was recording music. I’m guessing he heard something similar with his recording gear as I’ve heard with my stereo gear. 

On another note, I pulled all of the LED’s to see if another bulb would make a difference but then realized I didn’t have any incandescents laying around but I did have a fluorescent so I plugged that into one of the sockets. For the first 5 seconds or so the light was like pulsating on and off and each time it came on the buzz would come from my speakers. Also the little light on the dimmer switch was going up and down with the light. It sounded like a light saber going back and forth. My dog was looking at me like surely this is Armageddon haha. I’m guessing the bulb just needed to warm up because it stopped flashing after a bit and stayed on. The buzzing wasn’t any better with the fluorescent vs LED. 

@harpo75 maybe for the sake of experimentation I’ll try some ferrite rings on the switch wiring and see if that does anything. 

dirte30 - That would probably help with RFI. Different sizes affect different frequencies. It can get pretty technical trying to examine the line noise for the frequency or frequencies that are causing the problem. But if you have some lying around it would be worth the experiment.

@durte30 

Did you just say that you plugged in a fluorescent bulb? Are you light fixtures meant for CFL lighting? Some LED’s will work with this type of lighting if they are compatible with the fixtures ballast. My guess again- the dimmer. I’d check to see if your dimmer is meant to work with CFL fixtures.

@durte30 DISCLAIMER: I'm  NOT an electrician. Read on at your own risk.

Please don't put a fluorescent bulb in a dimmable fixture. From what I understand fluorescent bulbs are designed to work in a fairly narrow voltage range. You can damage the bulb and perhaps your dimmer.

Through a surfeit of caution I've installed several dimmers and LED bulbs in my home and managed to not kill myself or burn down my home. I like Lutron products as their website has some handy on-line tools for the do-it-yourselfer.

Phono sections tend to be very sensitive to EMI so I'm not too surprised by your experiment. You might talk to an electrician about checking your home's wiring.

OTOH, I'm of the opinion that unless you stand on a ladder touching the fixture while you're listening to music, you might be able to just leave well enough alone. Remember the old "Hee Haw" skit?

Patient: Doc it hurts when I do this. *waves arm around*

Doctor: Well, don't do that! *smacks patient with rubber chicken*

Happy listening. 😉

@designsfx they are just normal light fixtures that used to have incandescent bulbs. The LED’s I got were advertised as an incandescent replacement that fit that socket type. I did put in a fluorescent bulb but only briefly and then removed it.

@musicfan2349 yeah I don’t plan on listening while touching the light fixture haha but now that I’ve heard the buzz I can’t un-hear it and will probably just put a normal switch in soon.  

You can’t use a dimmer for fluorescent fixtures 

For AC filtering of the light something of this nature might work. They need to be wired inline to the dimmer switch.  These particular ones are way more current then you need but I was looking up units that would cover at least 2-1/2 amps for my needs. 
https://www.digikey.com/en/products/detail/schaffner-emc-inc/FN2090A-6-06/1997013?s=N4IgTCBcDaIGIDkwAYCcyCCBaAbF5OIAugL5A

Or this:

Off-topic, but do you use your turntable immediately adjacent to your speaker?  If so, then I would anticipate experiencing problems much more significant than this finding.

@vinylandtubes Yes I do but I haven’t noticed any issues there compared to when it was placed further from the speaker. Are you thinking from vibrations or something else?

Off-topic, but do you use your turntable immediately adjacent to your speaker? If so, then I would anticipate experiencing problems much more significant than this finding.

If it was magnetic field I would agree, but I suspect that this is either voltage field, or noise coming in on the ground or neutral side.

It could take an O-Scope to figure it out.

Since the foil wrapping ameliorated the effect, then we can probably rule out the ground (and any added capacitance added in when it was touched.)

which leaver us with whether the tonearm tube is metal, plastic, wood, etc.?
I do not think that foil wrapping metal should affect it.
If it did it could be the ground of the tone arm, if there is any.

What is the tonearm made out of?

And if the arm is not conductive, then maybe the wires inside are not twisted at all. But I am not sure if is any concern.

While it is pretty interesting, I am not sure if it is a problem that begs a solution?

@durte30 Yes, vibrations first came to mind.  Glad that you’re not experiencing any such issues.

The metal light fixture is grounded. Your body is another path to ground. Touching it creates ground loop hum. Very low in level. But phono stage is very high gain. One might even say Max.

@holmz The tonearm is carbon fiber, the clearaudio ‘Satisfy Carbon’. I wasn’t really looking for a solution with this thread I just thought it was something interesting to share here. Although after a handful of people recommended ditching the dimmer for a regular switch, I’ll likely do that soon because now if I ever listen to a record with the lights on I’m going to think I hear the buzz.

@vinylandtubes Before purchasing the turntable I’d read some reviews of people having a lot of skipping issues just from foot falls. I had a local countertop company cut and polish a piece of scrap granite to the dimensions of the tabletop under the TT. I’m not sure if the granite is the reason I’ve had zero skipping/vibration issues but it certainly doesn’t seem to hurt. 
 

@edisoncarter Interesting, thanks!

holmz The tonearm is carbon fiber, the clearaudio ‘Satisfy Carbon’. I wasn’t really looking for a solution with this thread I just thought it was something interesting to share here. Although after a handful of people recommended ditching the dimmer for a regular switch, I’ll likely do that soon because now if I ever listen to a record with the lights on I’m going to think I hear the buzz

For sure it is interesting.
That is why is would be nice to know the mechanism that causing it.

I agree on replacing the dimmer, the other option would be to replace the lights if incandescent or halogen are available, and probably the dimmer.
Whether it helps or not I also like the orange colour more, even not around halloween.

The last house had incandescent lights, and the new one has LEDs.

If you change the dimmer and keep the LEDs, then it would be interesting to know if touching the frame results in the same deal happening.

I am assuming that the frame is tied to the safety ground, which means that there is likely some difference in ground potential.
But if that were the case then it make little sense that hum is 60/120 Hz, I would think you would need a lot more voltage.

It would also be interesting to just get an extension cord near the tone arm to see if that also induces the hum.

I had problems with an appliance (Anova Precision Combi Oven) that caused a terrible buzz and excessive heat in my toroidal transformer in Mac amp. The variable speed fan seemed to be the culprit, causing "DC in the Mains". My understanding is that light dimmers are notorious for causing the same issue... I bought a DC Blocker which helped, but didn't solve the problem - so I had to ditch the appliance. Your issue sounds different, as you've described a different symptom, but my experience has made me very leery of dimmer switches... 

+3 bad or improper dimmer switch.

"Hey Doc, It hurts when I touch this...."

Doc:  "Don't touch that!"

I had a similar issue in my music room. All outlets (PS Audio) plus recessed LED lights were on the same circuit. The lights were connected to a dimmer switch. I had a terrible hum coming from my speakers when the phono input was engaged. Once I disconnected the dimmer and the lights put on a simple on/off switch most of the hum disappeared. But not all. I am awaiting an electrician to physically move the wiring for the lights to their own circuit in my box.

Why is touching the ground (lamp body is normally grounded) with a human body (fairly well insulated from ground, assuming shoes, ladder, carpet) getting a signal to the tone arm.

The tonearm is carbon fiber, the clearaudio ‘Satisfy Carbon’.

@durte30 When I saw this question my first thought was to ask what the arm tube was made of. I suspected Carbon or something like it and you just provided confirmation of that theory.

The reason this is happening is the arm tube is supposed to provide shielding to the cartridge wiring. Carbon isn't particularly good at that so is more susceptible to this kind of thing. I really doubt you'll get much relief from a different dimmer but they are cheap so its worth a shot.