DIY Dimmer question

[gossamer]

I want to make a dimmer(s) for my lights. I'm thinking of making one out of a standard light dimmer mounted in a metal project box with a plug-in on each side. Plug the light into one side and the extension-to-wall into the other. Use 110v wire inside to wire it together.

I have a few questions before I do:

Is there a better DIY dimmer plan/design you can recommend?
Is anyone else using DIY dimmers, should I find a "real" dimmer (aka pay money for a manufactured one)?
Are there some potential problems to watch out for like bulb fatigue, fire hazzard, etc. (Arrie light kit and Lowell Pro and Tota lights)?

If I ought to buy some dimmers, where should I look, which are good ones, and how much should I spend per dimmer?

Thanks in advance. You guys are always very helpful.

[Barry_Green]

Search for Walter Graff's article on how to build homemade dimmers, he offers plans for up to 2000w dimmers.

[J_Barnes]

I've built several dimmers using common 650watt rotary wall dimmers set into metal outlet boxes. I've also built a bunch of less robust dimmers to tame down the FCs of practical lamps, and both versions get used quite often on location.

I've used a variety of different dimmers (linear/rotary and widely differing prices) and what I've found has shown little difference between most of them. I like the operation of the linear throw switches, and having an added on-off switch can be very handy for repeatability, but the only real benefit of more expensive dimmers comes in the increased durability.

What I've found with buying cheaper dimmers is that they're more succeptable to grime getting inside and causing the voltage to wobble a bit, at which point you just need to switch out the dimmer itself.

As long as you use high quality parts, rated for the current you're going to carry, you shouldn't have any safety issues or fire hazards. These things are designed to work inside homes in a stationary environment, so you have to take some steps to reduce the wear and tear, but in general they're pretty safe.

I've made 1k dimmers, but they're a lot more expensive for parts. I wouldn't make anything to carry a load higher then 1k, it's just too much risk.

In theory, if you're not flipping the current up and down and turning the lights on and off rapidly, using a dimmer should actually prolong the life of the bulb...but understand that by using a home-made piece of equipment, you're not going to be covered for any damage to rental equipment.

Also, you're going to notice some serious noise once you begin to really dim things down, some bulbs sing more then others, but they're really only useful dimming a maximum of about 30-40%, and your color temperatures are going to drop really fast past about 90-85% of full.

If you can scrim a light, it's always more effective then dimming, but dimming 5-15% can really add a lot of control to your lighting.

[Scottdvx100]

For those with simple dimmer needs Smith-Victor makes a 600Watt version for $35 Doesn't have a ground (2-pin) but seems to be fine with 200 watt china balls and similar lights.

You can buy it and ready to use 1k dimmers at http://www.jcxex.com/ and I'm sure other places.

[Zoomforce]

I made a 3 outlet dimmer that is nice because 3 lights plug into it with one power cord going out, so it saves cables and you have one box controlling 3 lights. Its all 650 watt dimmers though, I wouldnt dim a larger light. another thing to note is that if you dim a light to 90% the bulb lasts 3x longer.

And for noise from dimmers.. look out. Dont even plan on using unbalanced audio cables, use Wireless if you can.

[Kugar13]

Why wouldn't you dim a light larger than 650w? I have two 1000w units I would like to dim, but would like your advice on that.

Also, what nose does dimmers create? I have been around a 6 set dimmer box used for theater and never noticed any noise, but I could have been ignoring it. Unless ur refering to crossing cables with a dimmer box....

Thank you!



I made a 3 outlet dimmer that is nice because 3 lights plug into it with one power cord going out, so it saves cables and you have one box controlling 3 lights. Its all 650 watt dimmers though, I wouldnt dim a larger light. another thing to note is that if you dim a light to 90% the bulb lasts 3x longer.

And for noise from dimmers.. look out. Dont even plan on using unbalanced audio cables, use Wireless if you can.

[filmat11]

If your just trying to save a few bucks...Use the dvxuser.com search engine to look up Harbour Freight dimmers or Harbor freight dimmers.Myself and a few others started a thread on here some time ago about these dimmers.
They will handle up to1500 watts and you can probably get them from anywhere from $ 12.99 to $ 25.00 bucks each. They are a Router speed controller....Different name, but they will work fine with 1K's.

[Kugar13]

Thank you for the speedy, and helpful, reply!


If your just trying to save a few bucks...Use the dvxuser.com search engine to look up Harbour Freight dimmers or Harbor freight dimmers.Myself and a few others started a thread on here some time ago about these dimmers.
They will handle up to1500 watts and you can probably get them from anywhere from $ 12.99 to $ 25.00 bucks each. They are a Router speed controller....Different name, but they will work fine with 1K's.

[moonlitnite]

I second Fimat11's vote for the Harbor Freight router speed controllers (i.e., dimmers). They were so cheap I bought two - they not only work great, don't generate detectable noise, but are really sturdy, too. However, a few in our group have noticed audible sounds on their unit (http://www.dvxuser.com/V6/showthread.php?t=81854&highlight=dimmer) (probably a manufacturing defect).

Anyway, for those die-hard DIYs, be aware inexpensive thyristor-based dimmers (triac or SCR) may emit radio frequency noise, here's a useful site (http://www.epanorama.net/documents/lights/lightdimmer.html#rfi). In essence, when the thyristor abruptly shuts off the voltage in the middle of a sinusoidal duty cycle, harmonic distortion (RFI) results without good filtering to smooth out the resulting waveform. Back in the old days, Variacs (http://www.epanorama.net/documents/lights/lightdimmer.html#variac) did a good job (although quite heavy) but over time they have been replaced with phase controlled systems (http://www.epanorama.net/documents/lights/lightdimmer.html#advanced).

Have fun, Michael

[Kugar13]

Wow! Extremely helpful. Thanks!!!


I second Fimat11's vote for the Harbor Freight router speed controllers (i.e., dimmers). They were so cheap I bought two - they not only work great, don't generate detectable noise, but are really sturdy, too. However, a few in our group have noticed audible sounds on their unit (http://www.dvxuser.com/V6/showthread.php?t=81854&highlight=dimmer) (probably a manufacturing defect).

Anyway, for those die-hard DIYs, be aware inexpensive thyristor-based dimmers (triac or SCR) may emit radio frequency noise, here's a useful site (http://www.epanorama.net/documents/lights/lightdimmer.html#rfi). In essence, when the thyristor abruptly shuts off the voltage in the middle of a sinusoidal duty cycle, harmonic distortion (RFI) results without good filtering to smooth out the resulting waveform. Back in the old days, Variacs (http://www.epanorama.net/documents/lights/lightdimmer.html#variac) did a good job (although quite heavy) but over time they have been replaced with phase controlled systems (http://www.epanorama.net/documents/lights/lightdimmer.html#advanced).

Have fun, Michael