Dimmer switches

WhiteStrat

Don't stare at the eye.
I've heard the horror stories about dimmer switches in studios, but is the problem caused by proximity or circuitry? In other words, can I use a dimmer switch without interference if my lights are on a completely different circuit than any of my sound gear? Or will it still emit it's bad mojo just because it's in the same room?
 

Chili

Site Moderator
I've heard the horror stories about dimmer switches in studios, but is the problem caused by proximity or circuitry? In other words, can I use a dimmer switch without interference if my lights are on a completely different circuit than any of my sound gear? Or will it still emit it's bad mojo just because it's in the same room?

I use a dimmer in my studio with no problems. I can hear the filaments buzz when I lower the dimmer, but it's not too loud. If I'm recording with a mic, I turn those lights all the way up (no buzz) or, just turn them off.

I have never had any RFI interference. I also have my lights on a separate circuit from my computer and interface, et al, however, I don't think that makes a difference. I think if the dimmer was putting out electrical noise, it would pass through the main buss in my power panel just as easily as if it were on the same circuit as my recording gear.

I do run EVERYTHING through an APC UPS which has excellent power conditioning for both battery backed outlets and non-battery backed outlets. So, maybe any electrical noise from the dimmer is filtered out.
 

Dogbreath

Im an ex-spurt
Yeah, I'd think with a decent UPS/power conditioner you'd be fine.

Is this a new thought for your studio build?
 

mshilarious

Banned
On the other hand, my dimmers are the devil, and that's throughout the entire house. Doesn't matter which circuit they are on (there are none on the studio rack or power circuits), they emit EMI, and lots of it. It's not a matter of noise on the ground or hot or neutral, it's in the air, man :cool: :( So power conditioning makes no difference (note that every piece of gear with a power supply has its own transformer and filtration anyway).

Now, I don't suffer because of it, because everything on the input side of my studio is balanced. But the bottom line is that dimmers, especially cheap dimmers, are noisy. I mean most people just tolerate EMI in things like guitars, but I don't. I mean, do your guitars hum? With your hands off of them? Why? It's not a "ground loop", because your guitar is grounded only in one place, right? Do they buzz more or less with the dimmer switch on?

If you want to eliminate the problem at the source, you need to get the top range, low EMI dimmers . . . sadly the manufacturers seem to have messed up their websites to the extent that I can't easily find them, but they do exist--they tend to be about $50 each, and you'll need to get them from an electrical supply house.

It might also help to use metal boxes for the dimmers, but almost nobody does that in residential anymore . . . and somehow I suspect conduit would be necessary too . . .

Oh, and Chili, if you have a voltage regulating UPS, unless you spent about $5K, its transformer will be emitting a nasty amount of low-frequency EMI if you get a sensitive circuit within a couple of feet. I have one because I don't have the $5K, but again, I'm fully balanced.
 

miroslav

Cosmic Cowboy
I use a dimmer in my studio with no problems. I can hear the filaments buzz when I lower the dimmer, but it's not too loud. If I'm recording with a mic, I turn those lights all the way up (no buzz) or, just turn them off.

I have never had any RFI interference. I also have my lights on a separate circuit from my computer and interface, et al, however, I don't think that makes a difference.

You may not notice anything with computer gear and/or stuff running off of UPS packs...(which can screw up analog audio, 'cuz most UPS packs are not putting out pure sine wave AC power---but that's another story)...
...but dimmers can be a real bitch with guitars, amps, pres and some analog gear.


I solved the problem by putting in a lot of low-wattage lighting...that way, if I want "room ambience"...I only turn on a few lights...if I need “stadium lighting”...I turn on all the lights.
No dimmers needed. :)

There are only certain dimmers (and I think they need to be installed a certain way) to guarantee NO issues....but most of the stuff at Home Depot will be at your own risk.
I tried some home-use dimmers ( Lutron(?) )...and they caused noise, so I removed them… but then, I have a lot of analog gear and amps.

Oh...I also use 2 dedicated 20 Amp lines run direct from the main breaker to a pair of Voltage Regulators, line filters, surge protectors...but of course...no matter how "separate" you run your lines...you have to realize that they will ALL connect via the Ground bar back at the main breaker box....so that's how AC noise can find its way into everything.
Balanced Line box is the only way to guarantee NO noise…but they ain’t cheap.
 

Ethan Winer

Acoustics Expert
can I use a dimmer switch without interference if my lights are on a completely different circuit than any of my sound gear? Or will it still emit it's bad mojo just because it's in the same room?

SCR type solid state dimmers radiate both through the power wiring and through the air. My best advice is to try one cheap dimmer and see what happens.

When I built my current house I had the electricians install cheap SCR dimmers and they buzzed like crazy. So I replaced one with an expensive ($90) SCR type that claimed to avoid the buzz, but it didn't so I returned it. Then I replaced all the SCR dimmers with variable transformers, and that solved the problem. But that cost $600 for all the dimmers needed throughout the house. I wrote it up as this article for Recording magazine:

Hum and Buzz, Clicks and Pops

--Ethan
 

moresound

Loud Sun Studios
Dimmers and florescent lighting should all be sent to the dump when it comes to recording.
Those all go off when recording and a few nicely placed lamps with small wattage bulbs are the way to go.



:cool:
 
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dintymoore

Guest
Over the years I've played in several clubs that had dimmers on the stage lights and most of the time they would buzz like crazy unless turned up full.

So when I made my studio I didn't use any. I also didn't use any fluorescent bulbs 'cause they cause problems too plus I hate that type of light.

I use 40W bulbs and like the ones GE makes called "Reveal", which are a more natural light. I am very light sensitive and if I'm under certain fluorescents I can feel like sick in about 30 seconds, I think it's the way they flicker real fast.
 
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dintymoore

Guest
Light, really, really affects how I feel. To the point where there are some stores I don't like to go in because I know I'll feel like shit if I do.

I bought some of those new energy saver bulbs - the squiggly fluorescents that screw into regular sockets, and I had to throw them all away.
 

WhiteStrat

Don't stare at the eye.
Thanks for all the replies guys!

In as much as the problem moves through the wires, I have good news for myself. Not only are my lights on a separate circuit from all the sound gear, the circuits aren't even coming from the same panel. And it's not a subpanel of the main panel either.

I've got 420 amp service, and it comes into the house as two supplies (300 & 120) each feeding it's own panel. My lights are on "basement east" which is a circuit from one source, but I'm adding the new studio circuits to the panel that's fed by the other circuit. (This all occurred to me late last night, went I went outside to kill the power to move some wires--dohhh, that's right--there's two big flippy-switchy things here!)

But inasmuch as the problem moves through the air--I could still be screwed. So I'm going w/Ethan's approach. I bought a dimmer and I'll try it out. If I have to switch it back--no biggie. But I spend a lot of time in my studio--it doubles as my office 3 days a week, and a lot of late nights doing freelance work. So it's worth the few minutes to see if I can have this little perk.
 

mshilarious

Banned
I have five lighting sources in my studio--in the floating cloud, there are compact flourescent cans (4) and incandescent cans (4). I have halogen tracks aimed at the walls (dark colored walls, 6 bulbs total). I have LED pucks (4) above the cabinet/rack. And I have a banker's lamp with a compact flourescent on the piano.

Here's how I use them: daytime, curtains open and CFLs to fill in. Nightime deskwork, CFLs + halogens (35W) + incandescent cans (stuffed with 15W bulbs). Recording/mixing, I turn off the CFLs. The LEDs are on 24/7, and the piano light is almost always on. The LEDs, those had 12 whites, I rewired each with 8 white, 2 red, 2 yellow (all superbright of course).

So long as there is another light source with the CFLs, the lack of red spectrum in the CFLs is not a problem. The CFLs + 15Ws gives me the equivalent light of a 75W incandescent, but only consumes 28W.

I have no hum problems from the CFLs. The dimmer switches elsewhere in the house . . . :mad:

I love my studio lighting design. Lots of little lights beats the pants off of a few big ones, and multiple switching eliminates the need for dimmers.
 

miroslav

Cosmic Cowboy
...there are compact flourescent cans (4)
:eek:

Right in the studio...?....and you have NO issues with them...???

I'm surprised.

Man...a few years ago I bought some of those spirally fluorescent bulbs that have the built in tranny at the base and are a straight replacement for typical incandescent bulbs, screwing right in.
I was using them for my outdoor lamp lights that are all around the building at various entrances and deck/patio areas.

So I'm in my studio one night...and I'm getting this weird buzz coming through my amps and monitors...it was not something I had before and it didn't sound like common AC noises...and I only noticed it at night.
I spent like...3 days hunting for the problem...finally using the main breaker box and thinking about what was different...I isolated one breaker that had one of the bulbs which was closest to my studio (about 25' away!)...and when I turned it off, the noise went away...I then looked at what was on that breaker...and there was that stupid fluorescent bulb. :mad:
I immediately removed every single one around the building and went back to using incandescent.

I was amazed that single, small fluorescent bulb with a very small transformer could cause that much noise throughout much of my studio gear! :eek:

My AC is pretty good in my area and virtually noise free…I’m not near any commercial/industrial areas…now towers…etc…but I’ve been considering a balanced line transformers for the whole studio, as they apparently eliminate ALL forms of AC noise and give your gear virtually perfect power. Combined with my voltage regulators…it could make an improvement.
The damn things are like $1200 for one 20 Amp box…and I have two 20 Amp lines (though I only run into the second 20 Amps if I like turn on EVERYTHING…which is very rare, but it’s there as a safety net and backup.

Oh...and not related to dimmers/bulbs but also an AC noise anecdote... :)

About two months ago I start hearing this intermittent buzz coming from my monitors...and then at one point also from my amps.
It was very low level, and for awhile I ignored it...but it really became a PITA when I was mixing. It sounded like those bug zappers...only very, very faint.
Again...spent a day chasing that ghost...finally isolated it to a coffer warmer plate I had in my studio! :D
Thing is...I had notice the coffer warmer wasn't really keeping my coffee warm like it use it...right about the same time the buzz started. Obviously, the electronics had become weak, and every time the warmer was turning on internally (I assume)...it would emit the noise.

Now I have a better/new warmer...the noise is gone and my coffee stays nice and hot (it's a 23W warmer!!!). ;)

So you really have to watch what you plug in around studio gear....
 

Chili

Site Moderator
...but dimmers can be a real bitch with guitars, amps, pres and some analog gear.
.

Good point. I don't use an amp for my guitars, just a modeler. I have one guitar with single coil p/u's and one with humbuckers; then a few acoustics and a bass. No problem with any. I do get noise if I get too close to my computer, but that's not the topic here.

I have a small flourescent over my desk and it does not cause problems, either. Just the dimmer if I have it less than fully On. I have a very small studio, so the three incandescents that the dimmer feeds can make the room warm quickly.

When I want ambience, I turn on just the lava lamp. :)

Lots o' good advice in this thread.
 

frederic

New member
I have my studio equipment, the computer, and other non-lighting connected to a sub-panel that's fed by a 60A 240V oil-filled, shielded isolation transformer. That killed all the electrical noise from the house to my studio in one shot and I got the thing used on ebay years ago for something like $250. I have it mounted on 1" thick 4" diameter (I think) rubber pads too in the crawl space.

The lighting in my studio is mostly on dimmers (four total) and connected to the house's main panel, I have an overhead two-tube 4' flourescent light, as well as those stupid orangy curly flourescent bulbs I can't stand. No hum, no noise, nada.

I think for me the isolation transformer worked out well. Before I installed it and the sub-panel, the electrical hum was beyond unbearable.
 

mshilarious

Banned
I’ve been considering a balanced line transformers for the whole studio, as they apparently eliminate ALL forms of AC noise and give your gear virtually perfect power. Combined with my voltage regulators…it could make an improvement.

Let's pretend we're gear designers for a moment. One of our most important tasks is to build a quiet power supply. Should we assume that our customers are using voltage regulators, isolation transformers, and UPS with pure sine wave inverters? How many customers do you think we'd have if we designed that way?

This is why most people using pro gear with balanced interconnections in between usually don't have any trouble no matter how dirty their power is. It's the unfortunate unbalanced connections and improper terminations that show problems. You have to consider whether it's easier to eliminate the sources of noise, or eliminate the paths for noise to enter your audio. It might be a combination of both.

When we talk about improvements with isolation transformers, we are really talking about quality of grounding. Maybe the trafo is the easiest solution. Let's talk about balanced power. Every bit of gear with a +/- internal power supply (which is most pro stuff) has a tiny little isolation transformer with a balanced secondary. So the question is the quality of the ground.

What is "dirty power"? It's power that is more squarish (usually more like triangle-ish) than sine. That means it has lots of overtones, which sound like buzz when then get in the presence range. Does dirty power really stress gear? Not really, the harmonics are usually still much lower than the fundamental 60Hz. So the ripple voltage seen by the power supply filter caps is dominated by the fundamental. And they should be way overrated anyway.

Now, if your power has nasty overvoltage spikes, that cries out for a solution. Every bit of gear should be designed to tolerate some level of overvoltage, but there are limits, so . . .
 
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