Lamp fixture causing RFI?

[AdmiralB]

I recently had to relocate my 'music room' due to some long-term guests (daughter's family is living with me while they build a house).

I put most stuff in storage and just moved a small rig into my bedroom. And I'm having helluva trouble with noise from the ceiling light fixture.

When it is on, I get a lot of noise through the guitar - even in clean situations (bass, say), and even with hum-cancelling pickups, although true single-coils are worse.

It is related to bulb type, but it's more complicated than that. Here are the salient points as I've observed them:

• The fixture is part of a ceiling fan, but it causes noise whether or not the fan is on (they are separately switched at the wall). If the fan is on, the noise level does not change; that is, when the lamp is off and the fan on, there is no noise.
• There are no dimmers anywhere in the house.
• The instrument is indeed the antenna - I can move around and the noise will wax and wane, though it never totally goes away, and it's not present with the guitar unplugged or zeroed on volume...meaning, it's not junk on the power.
• The lamp makes noise with CFLs and LEDs, but not with incandescent bulbs.

Now, that last point seems like the obvious answer, right? It's a bulb thing. Except.

My old 'music room' was next door, and it has the same model fan/lamp fixture (although it has a one-foot lower ceiling). And its lamp made no noise with any kind of bulb, CFL, LED, MBA, BMF, et al, etc. and ad nauseum.

So it's a combination of non-incandescent bulbs in this fixture. If I walk out of the room (with a wireless) into other parts of the house, there are plenty of other bulb types around and I don't get any noise elsewhere.

Thoughts?

[olddawg]

I recently had to relocate my 'music room' due to some long-term guests (daughter's family is living with me while they build a house).

I put most stuff in storage and just moved a small rig into my bedroom. And I'm having helluva trouble with noise from the ceiling light fixture.

When it is on, I get a lot of noise through the guitar - even in clean situations (bass, say), and even with hum-cancelling pickups, although true single-coils are worse.

It is related to bulb type, but it's more complicated than that. Here are the salient points as I've observed them:

• The fixture is part of a ceiling fan, but it causes noise whether or not the fan is on (they are separately switched at the wall). If the fan is on, the noise level does not change; that is, when the lamp is off and the fan on, there is no noise.
• There are no dimmers anywhere in the house.
• The instrument is indeed the antenna - I can move around and the noise will wax and wane, though it never totally goes away, and it's not present with the guitar unplugged or zeroed on volume...meaning, it's not junk on the power.
• The lamp makes noise with CFLs and LEDs, but not with incandescent bulbs.

Now, that last point seems like the obvious answer, right? It's a bulb thing. Except.

My old 'music room' was next door, and it has the same model fan/lamp fixture (although it has a one-foot lower ceiling). And its lamp made no noise with any kind of bulb, CFL, LED, MBA, BMF, et al, etc. and ad nauseum.

So it's a combination of non-incandescent bulbs in this fixture. If I walk out of the room (with a wireless) into other parts of the house, there are plenty of other bulb types around and I don't get any noise elsewhere.

Thoughts?

Make sure the fixture and the box is grounded. If you still have problems, you said it's a temporary situation. Put a cheap portable lamp near where you play, leave the offending fixture off, and be done with it. Life is short.

[nosaj]

It's called hash I beleive. Have you ever broke open a cfl or LED bulb. There are circuits in there, some have enough components to make a fuzz box. A regular light bulb is just a fine wire.

nosaj

[AdmiralB]

It's called hash I beleive. Have you ever broke open a cfl or LED bulb. There are circuits in there, some have enough components to make a fuzz box. A regular light bulb is just a fine wire.

nosaj

Right, but that doesn't explain why CFLs and LEDs worked fine in the other room. I understand why they make noise...but they oughta do it everywhere and not just a single location.

I think, anyway.

[Rob's Radio-Active]

Right, but that doesn't explain why CFLs and LEDs worked fine in the other room. I understand why they make noise...but they oughta do it everywhere and not just a single location.

I think, anyway.

I second the grounding of the fixture. Although it could be just the way the wiring is routed to that fixture, too, or whether or not the wiring to it is in conduit or romex.
Rob

[Richard]

Make sure the fixture and the box is grounded. If you still have problems, you said it's a temporary situation. Put a cheap portable lamp near where you play, leave the offending fixture off, and be done with it. Life is short.

I wonder how much of life is wasted trying to solve problems than can be avoided. I know I've spent a lot of time just because I don't want the problem to win.

[Justin Thomas]

I play a Tele with Duncans, wired with a 4-way. I been experiencing the same thing in PA, where I just moved again. I don't know if it's the bulbs, so much as when everyone has their chargers plugged in, etc. There's so much digital gadgets running on the wifi, etc - ALL of that junk. Earlier tonight the noise wasn't nearly as bad as I remember it, and it was only awful on the neck pickup (I have a 4-way switch, so my cover is disconnected). But when I was here in spring, it was awful! There's a mix of cfl & incandescent, and a few dinners in the OTHER half of the house, but it's also a 150-year-old building, so who knows how it's wired!

Sucks, any way you look at it... "I supersize with you!"

Justin

[Steve A.]

Right, but that doesn't explain why CFLs and LEDs worked fine in the other room. I understand why they make noise...but they oughta do it everywhere and not just a single location.

I think, anyway.

Perhaps in one room the outlet powering your amp is on the same circuit as the light circuit and in the other room its not... And I agree with the suggestion that you check that the fixture in the bedroom is actually grounded (as required by code.)

Steve A.

[nosaj]

Right, but that doesn't explain why CFLs and LEDs worked fine in the other room. I understand why they make noise...but they oughta do it everywhere and not just a single location.

I think, anyway.

Same exact bulbs?
nosaj

[Steve A.]

Right, but that doesn't explain why CFLs and LEDs worked fine in the other room. I understand why they make noise...but they oughta do it everywhere and not just a single location.

I think, anyway.

Same exact bulbs?
nosaj

My guess is that the fixture in the bedroom is not properly grounded. It is easy enough to check with an extension cord, an electrical meter or DMM, and a stepladder if needed. (For electrical work I like the stick-type meters that vibrate or buzz when you have voltage, especially if I am standing on a ladder!)

Put one probe into the narrow hot slot on your extension cord socket and touch the other probe to bare metal on the body of the fan. If you get no voltage the fan is not grounded. To be sure try putting the first probe into the wider neutral slot on your extension cord (if you do get voltage that way the room might be wired up backwards which could also explain the difference between the two rooms.)

Steve A.

[AdmiralB]

I've considered the grounding issue. I've verified that it's wired as such (which isn't easy since its power is taken from the fan), but not that the box itself is proper. As suggested, it's easy enough to do a continuity test with an outlet, though.

But what effect would grounding really have on a lamp socket? All it will prove is that the base of the fixture is connected to earth. The sockets themselves have no earth connection, there is no 'shielding effect' of a chassis. From a theoretical perspective I can't imagine whyt the lack of a ground would really matter.

And in response to another question...no, not same exact bulbs. That's a fair criticism. Bulbs from same package, yes, but not same exact bulbs. The fact that it happens with pretty much every non-incandescent - and that bulb type doesn't seem to matter anywhere else - never led me down that road.

[AdmiralB]

I wonder how much of life is wasted trying to solve problems than can be avoided. I know I've spent a lot of time just because I don't want the problem to win.

Yeah. In this case, it's a hassle. In the daytime, it's no problem, but the only other lamp is on a nightstand in the corner (containing, I should say, LEDs), and it's not bright enough. The obvious solution is "just use incandescent", but with the paucity of choices these days I either wind up with Mama Bear or Papa Bear - either too bright or too dim.

The house was built in '98, so I can't blame it on antiquity.

[AdmiralB]

Hi Steve!

I did think of that, but it did this before I moved (I forgot to mention that); when my stuff was in the 'music room', if I walked into the bedroom with a guitar (again, wireless), it'd go nuts with noise. I've verified that those two rooms are on different circuits.

[John_H]

Is there any concealed wiring above your ceiling. There could be a junction box, or a low voltage transformer in close proximity that's emitting the RF.

[AdmiralB]

Is there any concealed wiring above your ceiling. There could be a junction box, or a low voltage transformer in close proximity that's emitting the RF.

No, I've been above it (the 'attic' is quite tall and I'm in the process of finishing it...'process' being measured in years, not months or weeks however); and I would think something like that would behave the same way regardless of bulb type?

About the only thing I can come up with that's actually different in this room is, the ceiling is a couple feet higher than anywhere else. I've never heard of 'angle of incidence' being important in situations like this, but when (you think, anyway) you have ruled out everything else...