http://www.environmentallights.com/shop/images/tech_specs/lr6.pdf

The term "low voltage dimmer" describes a dimmer used to control a low voltage load but the dimmer itself is line voltage. Magnetic transformer low voltage loads require a special design to eliminate the small amounts of DC voltage created by regular dimmers. This costs extra to put in the dimmer so most don't include it standard. Without this the transformer can overheat. Both dimmer and transformer can be damaged. Electronic transformers don't like the way a standard dimmer or magnetic low voltage dimmer chops the power at the leading edge of the sine wave and require reverse phase dimming instead which cuts power at the trailing edge. Many LED fixtures use electronic drivers that require electronic low voltage dimmers. There are many ways to drive and dim LED lighting and they must be compatible or premature failures will occur.

Here is a link that might be useful: Lutron's list of compatible LED fixtures.

Thanks guys for the links. From the links I still see that the particular low voltage dimmer that the electrical distributor says he sells a lot of for that light are not on the recommended list. As mentioned I wonder if they have been analyzed by CREE and failed or whether they just haven't been tested yet. I guess I can take my chances and hook up one of them and see if it works but if it is going to cause premature failure of the LED I won't know for a while. If it causes noticeable acoustic noise that would be No Go.

Have you guys used the CREE lights and if so what dimmer do you use?

I use Leviton Monet with my LR6.

davidtay,
Looking at CREE's list of recommended dimmers I see that there is not a Leviton Monet listed. If you are happy with it - no acoustic noise, no flickering, decent range of dimming - that sort of confirms my suspicion that the CREE list is incomplete.
As I search for Leviton Monet I am learning that there are a lot of different models in that line. Do you recall what the model number is?

regfman,

From the Cree list of suitable dimmers

*The presence of a dimmer on this chart is not a guaranty or warranty of the compatibility of the LR6, LR4 or LR5 product families in any particular installation. The absence of a dimmer from this chart does not necessarily imply incompatibility. Please reference the dimmer manufacturer's instructions for installation and further product information.

I don't recall the model numbers.

No buzzing.

The Monet is really more suited for commercial applications (lots of lighting). Min load is 60W.

Lutron may have more choices/ be more suitable than Leviton.

regfman,

The Cree lights work with normal incandescent dimmers.

David

I know the dimmer that I currently have that is left over from the incandescent cans makes noise - actually it was a few weeks ago that the electrician tried it and I can't remember whether the light was making noise or the dimmer. I think the noise was coming from the dimmer. We decided it would be best to get an appropriate dimmer.

I think the thing that I will take away from this discussion is what you pointed out about the absence of the dimmer from the CREE dimmer list does not mean the dimmer doesn't work, combined with the fact that the electrical supply store in San Francisco where probably a lot of greenies buy, recommends the DVELV-300P. I'll give it a try.

regfman,

If you check the types of dimmers on the CREE dimmer list, most are for incandescent loads and there are a few (Lutron) that can be used with Magnetic (inductive) low voltage loads.

Not to say that you shouldn't give it a try.

I have three circuits in my condo using LR6s. Two use two fixtures each, and one uses three.

I have done tons of research on this issue, speaking to both Lutron and Cree customer service and eventually Cree application engineering.

I have been assured that dimming will lengthen, not shorten the life of the LR6s.

My understanding is that the potential failure mode of using Maestros with LR6s is flicker at some dimming levels.
I understand that flicker might occur if there is significant high-frequency electrical noise in the environment. 60-Hz noise like from motors in a fridge will not cause flicker, but old fluorescent ballasts might.

I have all new wiring in my home in MC, and my fluorescent ballasts are new Philips Advance DALI digital control.

I have decided to take the risk and am installing Maestro dimmers on these three LR6 circuits next week. I will report on my success.

@pauldavisseattle - how did the maestro dimmers work out? i'm buying some soon and have looked at those and the leviton illumatech ipi06 for my cree lr6s

if you get this anytime soon, let us if you're happy with the maestros.