One thing to note here is that as far as cheapo 5mm LEDs go, you might end up having the stock LED with 10000k or colder and godawful tint. There are no minimum to the quality controls there.
I am new to the CRI things and my setup (Colormunki Photo + ArgyllCMS) might be poorly missused but from what i see on my cheap lights they range from a CCT 11000K / CRI 74 (R9 -20) for the better to something that Argyll can't even understand telling me something like 999911K / CRI -1 for most of the others.
My guess is that the blue peak is so high compared to any other color that the calculation fails
As mentioned above, intermediate CCT and CRI. Duv will be lower than either emitter, which is a benefit.
The cheapo LED’s I have tried have a higher forward voltage than the Yuji’s, which means also than these replacements. The result will be your high CRI emitters are driven harder than your low CRI emitters. It might not be enough to cause a problem though.
The cheapo LED’s are also usually a ~15 degree beam. The much tighter beam will mean major tint deviation across the beam. It might be possible to resolve by sanding the dome of the cheap LED’s.
I have mixed equally numbers of 3200K and 5600K Yuji’s with similar beam angle and forward voltage in a test, and the result was really good, around 4500K. I only tested it a limited amount, but I actually liked it slightly more than the only Nichia 219B, SW45K light that I own.
Thanks for the replies. I knew the cheapies were cold, but 11,000K? WOW!
So, if I tint mixed like I suggested above, I would still end up with a very cold light, at a bit over 6700K average? Yikes!
Well, that might work in my favor, actually. Since djozz tested these LEDs at up to 100mA, they should do okay, and turn the overall light output a bit warmer than if all the emitters were putting out equally. Maybe, it might even get into the 4500K - 5000K range overall.
That would be a problem. I guess I could solve that with a bit of DC-Fix, or by sanding the domes like you suggested. Or both.
As a fair warning, 11000k is not the upper limit of how bad these can be.
The “6500k” cheapie samples I know was pretty darn cold 50000k. Djozz has tested it. Ewww.
You cannot expect any sort of consistencies as far as the el cheapos are concerned.
50000K? :-P Is that possible without the stuff emitting some nasty UV frequencies? Also, that cannot look very good.
50000k corresponds to X,Y of (0.227,0.228) which is not that far from 20000k (0.250,0.250).
Once you slip past 10000k in terms of x-y, it’s seem really easy to slip into 6-digit figures.
I have my theory that the light mixes by averaging the CIE x-y coordinates.
10000k on BBL: 0.280, 0.290
3000k on BBL: 0.431, 0.404
The resulting light will be: 0.358, 0.347
That corresponds to ~4500k and –0.0073 duv
If that works out the way I theorized, then you might want to throw in a few (and only just a few) green LEDs to pull the duv back closer to the BBL.
10000k (DL locus): 0.278, 0.293
3000k on BBL: 0.431, 0.404
The resulting light will be: 0.354, 0.349
That corresponds to ~4600k and –0.0048 duv
Ulrich - RO247700139TH
EricJ2190 - RO247700142TH
TBone - RR278755013TH
So, the CCT isn’t an exact average of 3000K and 10,000K, but an average of the underlying positional numbers? And those don’t scale linearly? That’s interesting. I really DON’T know much about light and/or color!
CIE coordinate itself is pretty linear.
It’s the CCT that is non-linear. You can look it up and see that the warm white part of the locus takes about 1/3 of the chart’s span. And the BBL locus is curved.
In all honesty, mixing unknown emitters is a bad questionable idea. Of course can be done, but you'll have to deal with a poorly predictable resulting tint and CRI mishmash. One of the most important factors to consider, if setting emitters in parallel, is you won't exactly know how they will share the driving current. This affects the amount of output from each emitter, and therefore CCT, tint and CRI. It will also affect the relative speed at which each emitter will age, and thus CCT, tint and CRI will also change with use.
When actual emitter tests are available you can at least know what to expect, i.e. you can more or less predict the final outcome.
For example, setting a LH351B 3000K CRI90 in parallel with an (MF) LH351C 5000K CRI90 at ≈1.5A would result in a 0.6A/0.9A current share given their Vf curves (planning to give this a shot sometime).
maukka did a measurement of a combination of a 3200K + 5600K Yuji: [Available again! - BLF special edition light] new Sofirn AAA twisty high CRI 5mm LED - #2061 by maukka
See the last measurement.
Nitecore Tube came in yesterday and I put one of these LEDs in, GREAT little light now. On top of the great color/CRI I’m very happy with the output level. these put low and high exactly where I would want them. Easiest 5mm swap I’ve done as well, putting Yujis into a traditional twisty was far more tedious (killed a driver in one).
Thanks for the quick shipping, rngwn!
Mine arrived — plopped one into a Photon Freedom — easiest mod on the planet : )
Nice warm and pleasant LED.
Cool white version is coming
along with a bag of 3400k with the same binning.
Has anyone put one of these in a .....free / just pay shipping Coast light yet ?
I had one slung by the lanyard on my sliding glass door handle for years but replaced it with a Jacob A60 ..Seemed more a more appropriate backdoor light..
5600K? That will be nice for tint mixing. There are many 12 or 21 or 51 UV led flashlights around where you could change the leds. The 3400K have a great color rendition.
The label says “5800k” but based on given X,Y it computes 5400k-5600k with duv .0014 - .0037
Sure, it is. To be safe replace 1 resistor. Reddit - Dive into anything