Dimmers

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Where the hell can I find some decent rfi suppressed dimmers? The ones Im using on my track lights are generic Home Depot ones and they SUCK! Way to much interferance when trying to record to PC!
Thanks,
Jim
 
Try Pioneer Breaker & Control Supply.
2216 B Rutland Drive. 2 Blocks E. of Burnet Road.
834-1011.

Last time I checked; several months ago, they had 'em.
 
Hey Michael, thanks, Ill give em a call, also, iffn' yer ever in the south Austin area, you should look me up, Id dig your input on my room and any advice you might have to offer, especially in the acoustic treatment area.
Thanks man,
Jim
 
Ok, Pioneer didnt have them, Graybar said "what?" and the cat at Herrells was a coplete moron, looks like Im just gonna have to live wthout dimmers,? fark!
Michael, Oak hill? damn, thats just around the corner from me!
Let me know when its a good time to come by and check that bad boy out! Looks like a lot of work equating to a lot of fun!
 
The home depot ones I put in were noisy also. Found out the hard way, lol. but they didn't cost too much. You could even hear the noise at the electrical bkr box panel. Well they shorted out and only work as on/off switches, but they sure are quiet now. If you find some let me know I think it really adds to the ambiance to be able to turn the lights down.

larry
 
I'm going to have to find some too, now that my connection has dried up. :p

They're definately not a Home Depot item. Electrical supply houses are the only place that are going to have something like that. And even they may have to order it.
 
Jim,

> Where the hell can I find some decent rfi suppressed dimmers? <

Solid state dimmers are not good for audio, period. See my "Hum and Buzz" article, third in the list here:

www.ethanwiner.com/articles.html

--Ethan
 
Re: Re: Dimmers

Each good dimmer has a filter choke inside. Those chokes help to filter out electrical noise that often causes hum to be picked up in sound system and musical instrument pick-ups. The slower the current rise is, the less noise is picked by sound system.

The chokes also help to eliminate 'lamp singing' that can cause audible noise to come from the lighting fixtures. Lamps with power rating of 300W or more tend to more or less acoustic noise when dimmed. If this acoustic noise is a problem can be removed by adding a series coil which limits the current rise time to around 1 millisecond.

In providing those filtering functions, the chokes themselves can generate a slight buzz. Fast current changes in the coil can make the coil wiring and core material easily vibrate which causes buzzing noise. A little bit of buzzing is normal with filtered dimmers. If the buzz from dimmer can be a problem it is recommended that the dimmer is placed in the area where this buzz will not be a problem.

As far as the 'bulb singing' concerned, a bulb consists of a series of supports and, essentially, fine coils of wire. When the amount of current flow abruptly changes the magnetism change can be much stronger than it is on a simple sine wave. Hence, the filaments of the bulb will tend to vibrate more with a dimmer chopping up the wave form, and when the filaments vibrate against their support posts, you will get a buzz. If you have buzzing, it's always worth trying to replace the bulb with a different brand. Some cheap bulb brands have inadequate filament support, and simply changing to a different brand may help.

Buzzing bulbs are usually a sign of a "cheap" dimmer. Dimmers are supposed to have filters in them. The filter's job is to "round off" the sharp corners in the chopped waveform, thereby reducing EMI, and the abrupt current jumps that can cause buzzing. In cheap dimmers, they've economized on the manufacturing costs by cost-reducing the filtering, making it less effective.

In very high power dimming systems the wiring going to lighting can also cause buzzing. The fast current makes the electrical wiring to vibrate a little bit and if the wire is installed so that the vibration can be transferred to some other material then the buzzing could be heard. The buzzing caused by the vibration of the wiring is only problem in very high power systems like theatrical lighting with few kW of lights connected to the same cable. Better filtered dimmers can reduce the problem because the filter makes the current changes slower so the wires make less noise.

Anyway, put an additional choke inside the "cheap" dimmer and most if not all the noise goes away. 40-100uh is usually enough.
 
Atta boy Freddie...

Write a whole article just to tell us to add anoter choke to the dimmer ;P

(just picking on ya!!)

Actually... with my luck I'd burn the place down tampering with an existing dimmer.

I'm not sure what I'll do for my studio. I've avoided putting ANY dimmers in the whole house because of fear of what they will do to the studio.

Velvet Elvis
 
Maaaan...

I'm a day too late... I've just let the electrical technician add two dimmers on the studio light... one for the booth room and one for the control room. I haven't tried them all, but is everything okay if I turn them off while on the session? (there's optional 4 more lamp on each room beside the one which dimmer'd that I can use)...

:confused:
 
Write a whole article just to tell us to add anoter choke to the dimmer ;P (just picking on ya!!)

Thats cool, no problem. I was trying to explain exactly what the problem is.

Actually... with my luck I'd burn the place down tampering with an existing dimmer.

Not at all, a choke is nothing more than a coil, wrapped over a ferrite core, rod, ring, etc. The wire is coated with a paint that prevents it from shorting to itself, or other items. Good dimmers have chokes in them to begin with for this reason. That and a few extra mylar 250V capacitors in the .05-.1uf range, typically.

I'm not sure what I'll do for my studio. I've avoided putting ANY dimmers in the whole house because of fear of what they will do to the studio.

There are noise-cancelling breakers available for most modern day breaker boxes, I found a set for my old 1950's murphy-compatible breaker box, so you put one noise reducing breaker on the lighting feed, and one noise reducing breaker on the audio/computer feeds, and you lose about 97% of the noise that way, even if you use cheap, poorly made dimmers.

This will cut the noise crossing power feeds, but it won't cut out the irritating noise lightbulb filiments make when they oscillate. That can be significantly reduced by trying different brand of light bulbs, or using commercial grade bulbs rather than consumer grade bulbs. The filiments are typically suspending in four or six places, rather than two or three places, so they are better survivors of being knocked around. Because the filiments are better supported, the wavelength between the filiment sections is much smaller, therefore the oscillation frequency is much higher, say, 250+Hz. Since your outlet provides 60hz, the bulbs don't "ring".

Avoiding dimmers entirely is the best solution. I am using dimmers here because I don't have the ceiling space to shove in a slew of cans for multiple wattage bulbs, but thats a very good solution. You have many lights in the ceiling, put all the 25W on one switch, 100W on another switch, then you have three lighting levels. Full off, 25W, 100W, and both. But then you go broke buying multiple cans :)

An industrial electrical supplier that your local electrical contractors go to can easily provide commercial grade dimmers though, ones with the chokes and the extra caps. Viola, done and go have pizza :)
 
The noise Im hearing is coming thru the headphones in the pre record status, and veries with the position of the switch, Im sure it would be heard thry the PA also if I was to turn it up, when I turn the dimmers down, or off the noise goes away, so, James, I think youll be just fine as long as the dimmers are off while youre working on an active session. BTW, if you read the info provided with most newer generic dimmers, it states that they are equiped with rfi suppression from the manufacturer. To what degree, I ave no idea.
Ive considered installing a "choke" in series with the dimmer which theoredicly should work somewhat, I just need to reflect back on my Ohms Law and refer to my old electronics books,,,,,, or,,, shitcan the dimmers alltogether. But I like the effect of the low light plus my colored studio cans produce.
Later,
Jim
 
Actually though frederic had a great idea...

Two varying levels of light on two completely seperate switches... although that means that many more holes in the ceiling of the studio...

I might have to consider that...

Maybe I'll just put 4 or 5 1000w PAR 64's where the drummer has to sit ;P

(joke)

Velvet Elvis
 
Ethan,
Dont think for a moment that I rolled over your post, thanks for the link and Ill absorb it in much more detail over the weekend.
Jim
 
Amped... I'm sorry... I didn't realize you're a drummer...


I'll repeat the joke a little slower this time so you can understand too ;P

BWAHAHAHAHAHAHA

Velvet Elvis
 
ohhh man, thats cold blooded, but funny as hell! Not all drummers have the IQ of a postage stamp ya know, some are much lower....
 
I might have to consider that...

If you can afford the extra cans, AND the ceiling space for the cans, its a fantastic solution. In the last business I owned I had this arrangement in both my 20x30 office and the neighboring conference room, just to control the brightness a bit (brighter for presentations, softer for solitary whiteboarding and laptop usage), and also to avoid flourescents altogether. I hate flourescents because I can see them flicker, as can about 5% of the population. This causes me headaches on a regular basis. This is partly why I work from home when I can, but when I'm in the office, I leave my office lights off and I have four $20 monochromatic halogen lamps around so I can see. Until my employer starts funding advil by the case, they can pay for halogen bulbs for my four lights :)

Maybe I'll just put 4 or 5 1000w PAR 64's where the drummer has to sit ;P

heh-heh. Considering my opinion of my last drummer, I'd say skip the lights, make the drum room soundproof, lightproof, and fireproof, and fill the room with natural gas, then say smoking is allowed.

Okay, I'm a prick.
 
Amped said:
"HEY!!!!! I'M A DRUMMER!!!!"
lmao, no respect......

Nothing personal intended. I slam everyone equally :)

See, I used to co-own a pro studio, trust me, I've seen it all. Standard whine for me actually.

Bass players snuffing butts on a hardwood floor, guitar players leaving string snips all over the place, drummers missing urinals, the list goes on endlessly.

Most of my customers (regardless of instrument or level of talent) were good people, I'd say about 93% to be inline with my 7% rule, which is:

"No matter how you slice society, whether by creed, race, social group, occupation, location, hobbies, education or fetish, 7% of those people are assholes".

:-D
 
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