The funny is that it’s not necessarily a Q5 in the first place.
Cree bins are 7% or so part. In terms of human perception, 400–800 is necessary for something to be seen as twice as bright.
The 7%, which works out to about 65 lumens, adds up though. T6 1C to U3 1C should be about 130 lumens, while going from a T6 neutral tint to a U3 cool white should be even higher, maybe closer to 200 lumens? Of course a lot more can be done to crank up the brightness, but the emitter is part of the equation.
Yes, it's part of the equation. With lights like the HD2010 that are already maxed out on current, there are fewer ways to get more lumens out of it. One way is a higher bin LED. Another is getting a lens that actually has an AR coating. Improved heat sink contact should reduce thermal sag. Dedome if you want more lux.
It's all about doing a bunch of little things to get a big result. Or wait a few years for a big jump in LED performance.
Until 2010, I hadn't bought a new LED light for almost a decade. The new light was probably an order of magnitude brighter than my old light. Then this year I bought a few more lights that are several times brighter. In a five years, I'll probably buy a LED light that makes my XML lights look like candle lanterns.
Fully agree. But I still don’t think it makes any U2 light obsolete 
Maybe I'm overstating it, but if the 1A and 1B tints for the U3 come through, and volumes become available, the U2 should be effectively replaced, and for those manufacturers that commited to it (Crelant, ThruNite TN30 and TN31, etc.), should be making the switch over soon. So if I was considering an expensive purchase, such as a TN30 or TN31, now is probably not a good time -- I would wait for the U3 version.
I do need to learn more on the differences between the 1A, 1B, and 1C - think they are all in the cool white range, but what are the advantages/disadvantages. Have to look up that Wiki again with the CREE info. The manufacturers are reluctant to reveal their plans because of selling off existing inventories -- they don't want us to wait.
I think you are all taking "obsolete" a little too literally. My interpretation of what he is saying is since the U2 emitter is still only available in CW tint, there is no advantage to using it when a CW U3 is available. The T6, even though 2 generations behind, is still desirable and useful due to the fact that you can get it in nearly any tint you could want. If you are not looking for a neutral or warm tint and want raw output and efficiency, why would anyone buy a U2 when the U3 is available? Hence, until the U2 is available in a tint other than CW, is has indeed been rendered temporarily obsolete.
Yeah, all those are CWs. Currently my color tastes tells me to stay away from the purple(ish) and green(ish) tint.
Tint Chart from Wiki. I like to open it up to the max for better view.
Eyes work logarithmically, so 7% is more meaningful than X lumens. 7% is indistinguishable unless you A/B.
I’m not sure why you’re comparing neutral to cw tints.
Just to clarify, a cool white tint won’t produce more lumens than a neutral if they are the same output bin (XM-L T6 3C vs T6 1A for example).
Tom E- the 1A tint you mentioned has a tint closer to planckian black-body radiator (the 1A tint more realistically emulates visible light that a filament radiates if it could be heated it up to about 6500K)
I don’t have any U3 leds. Don’t plan on buying any, till I can get them for $2.50@, just like the T6 leds are now.
Where are you getting T6 LEDs for $2.50??? 
Aliexpress.
If you’re unlucky, the difference could be much smaller, right? A top T6 is ~975 while a low bin U3 is ~1040 so it could be as little as ~75 lumens.
(Of course, on the other side of the coin, you could be going from ~910 to ~1105. :laughing:
link? 
He's actually using taobao.
It’s useful to remember that these are the same emitters (XM-L) coming out of the same productions process. While I haven’t seen it (or looked for the XM-L) the overall distribution for other emitters I’ve seen is the normal distribution. That means the top bin coming off the current process is way down in the tail end of that distribution. The bins may be by differences of about 7% but typically the difference between a sample of the highest bin and one of the next highest bin will be+ less than 7%+ because of the distribution.
The CCT is distributed too. Cool white XM-L emitters are using the same phosphor process and they just bin them based on the result. When the flux bin is less common there’s less (or no) option(s) to pick tint bins for manufacturers so they tend to buy the bulk top flux bin… and the tint lottery is at it’s most extreme. Since the lumen output is measured based on a scale to approximate brightness as seen by the eye there’s some interesting other potential tint issues. Not all wavelengths are created equal for the lumen measurement. Green light of the same energy is more lumens than blue for example. The small difference between a U3 flux bin and a U2 tint bin could be all or mostly tint based. That’s awesome if you like the tints that count more towards lumens. Greenish tints aren’t usually high on people’s list of desires though.
The output differences are basically imperceptible but the tint lottery is perceptible.
Meant to address this piece as well. Almost impossible to compare a single sample for the heat difference. The biggest driver there is the Vf variation (which last time I paid attention Cree wasn’t binning for but was around 20ish percent variation.) You could also have a T6 flux bin that runs remarkably cool and a U3 that had a very high Vf burning up the light. Funnily enough the T6 flux bin might actually be brighter a couple minutes into the run once you consider lumens lost to heat buildup and potential driver issues pushing slightly less current to the high Vf LED.
I think the U2 is still an awesome led. It can be pushed hard and kept under good heat management. The U3 is not that much of an eye opener in my opinion. When these LEDs reach the 1400 lumen range the difference will be very noticable and the quest to manage the heat omitted will be on. Bigger hosts, more copper will likely take the stage with many designs.
Do or could LED manufacturers ever gimp samples aka cpu production to artificially segment the market or meet some part demand?
[quote=agenthex]
Not that I am aware of. In theory they could sell some of the top flux bin as the next highest bin. Unlike a CPU there’s not the timing logic to limit it down below what the chip would handle or another core to disable. It’s a much simpler device and a much cheaper one; that makes putting costly time and effort into segmentation of the market for price discrimination less likely to pay off. I haven’t seen much in the way of price discrimination till you get to the light manufacturer’s where they try to trumpet the highest bin special models.
In the budget realm there is very little way to tell if some of the manufacturers aren’t simply “relabeling” whatever emitters they get their hands on as the highest bin. The emitter itself looks the same because it is the same part. The light introduces more variables so it’s hard to test even if you had an integrating sphere. Unless there’s a marking on a star that an intervening sub manufacturer put on their…
everything’s a U3!!! Including the cool white T5 that was runt of it’s wafers litter.