somebody wrote:Hmmmmm. Any idea which transformer the issue is with? Below is an email I just received from the company I purchased the lights from.
I have a dozen DR450's sitting on my desk now. Initially testing without a dimmer shows they work fine with the Osram Redback electronic transformer and a older ATCO wire wound transformer.
Adding a dimmer however and there is trouble. I tried 4 permutations.
1) ATCO TM50-2 + Clipsal universal dimmer.
2) ATCO TM50-2 + HP leading edge dimmer.
3) Osram Redback + Clipsal universal dimmer
4) Osram Redback + HP leading edge dimmer.
1) and 2) flickered badly. Which was surprising as the wire wound transformers should be more compatible. Would be totally unacceptable in normal use in my opinion.
3) Didn't dim very far, certainly not anywhere near 100% to 0%. This would be maybe be acceptable for some people.
4) Flickered slightly when nearly dimmed to 0%. Would really annoy me, but some people might be able to deal with it.
Also when powered on with the dimmer already in the dimmed position there was a 1 or 2 second period of bad flickering in cases 3) and 4) then it stabilises. Which is a bit of a shame as one of the feature of LEDs was immediate 100% output.
This was all done with a single globe in the circuit. There might be significantly different behaviour with multiple globes in the circuit to provide additional load.
In short, they don't dim as well as halogen lights.
Two other minor comments. The lens cover is clear plastic. Not glass. I find it hard to imagine the clear plastic will still be clear in 30 years time. Secondly the shape is different from a normal MR16 halogen. So I had a problem getting it to fit in one bracket. There are three small cut outs in the plastic lens that need to be carefully aligned, if your bracket has nubs on it.
I'll be doing some more testing over the next week and post some additional results.