So I finally found something interesting about the SST-40, and it’s a Neutral White SST-40:
https://www.mouser.ca/ProductDetail/Luminus-Devices/SST-40-WDS-F50-N3501
Non-stocked obviously, and N3 flux bin only.
And a 5700K version too, or was that one already there? So they have the cool whites covered then, just like with the SST-20. That generates some more expectation…
Just tested the SST-40 N5 BC VH bin, I’m here to say that a full 30Q on FET driver did not kill the LED
Thanks for sharing, how is the tint on those? I have the N4 Kaidomain was selling but it looks too cool blue for my taste, also have the new N5 but haven’t tried it yet, is it less blueish?
lol funny thing you said that, I in fact love the blue in the N4, the N5 BC VH is too warm for me, if i had to guess i’d say its around 5700K
I did some testing of three dedomed or sliced SST40s including an N5 BC I got from KD. I’m measuring the lux above the LED which gives me a number proportional to the total lumen output of the LED.
First I have the first SST40 N4 BA I ordered from KD when it first came out. I was able to gas-dedome it and not kill the bond wires.
Then I have another N4 BA I got from mtnelectronics that I did a close slice on, similar to here. Getting the silicone very thin is important to get the highest luminance.
These two emitters had almost identical output numbers which is a good indication that the close slice is effective.
Then I measured a new N5 BC from KD that I close sliced. The output and Vf is nearly identical to the N4 BA I measured above. The output should be about 7% higher and the voltage should be 0.2V lower.
I’m disappointed because I was planning on using these to boost the output of a single cell triple SST40 mod.
I like the 5700k temperature, I guess I am going to go change the N4 to the N5 then… Thanks for sharing!
I guess you measure the lux at exactly 1 meter of distance right front in mule mode, then multiply that by some constant assuming lambertian emitter and whatever whatevers LoL. Could you elaborate a bit more? Thanks.
Is there a high cri version of sst-40, like the 95 cri sst20?
No problem
Not to be known available. There's NW tints vaguely referenced here on BLF, but if you go to their website here: https://www.luminus.com/products/white, there's only 6500K and above listed, and CRI is listed as 70 typical.
But here at Mouser they list 5000K and 5700K: https://www.mouser.com/Search/Refine?Keyword=sst-40. The weird thing is the "WDS" in the part # is not referenced in the datasheet, so these new 5000K and 5700K aren't really covered in a datasheet from Luminus. It takes qty 500 min and 5 weeks delivery to get NW but looks like CRI is still 70.
To clarify the #'s, the SST-40 N5 BC VH bin referenced above is, I assume, is the BC bin, which according to the data sheet is 6500K?
Yes, that’s pretty much it. More info here. XHP35: measured luminance and forward voltage - #19 by EasyB
it says 6500K but it’s noticably warmer then my N4 BA bin (I got both the N4 BA and the N5 BC) the N4 BA looks brighter to my eyes due to the cooler tint
Does anyone know if there is high cri version of the sst40 led?
Spec sheet here: https://www.mouser.com/datasheet/2/245/Luminus_SST-40-W_Datasheet-1499204.pdf
says one 70 CRI on page 7 - "WCS", where S is for standard 70 CRI. Least this is today of what we know. The SST-20's fill the high CRI niche for now.
Basically high CRI means lower output - that's how it seems to be working now. What's new in the last couple years is we can get NW tints in high output bins, but the high CRI kills the output.
Going to re-post this to this thread as a reference since I took the time to do it. This is two unverified bin SST40’s in two different lights (D80 and Enogear EC21, basically Nightwatch NS22). Both were sold to me as 6500K which I suspect is accurate.
I did this to clarify to myself and others what to expect with a slice vs dome on LED and to predict what an SST40 5000K might do with dome on/off, assuming it behaves similarly.
Here are measurements from two different reflector lights and LED sources taken at the hot spot:
And the wider spill:
In my opinion the 6500K+ with dome on makes my eyes go 
if I look at the spill. It’s awful and basically unusable. The hotspot is generally very intense and far away so it matters slightly less and is probably passable if you need the output.
After slicing, the shift is still noticeable but much better in the spill. The spill becomes more faint so the shift is less bothersome and the hotspot is so intense its hard to notice much difference there.
TL;DR de-dome these at high output or use another LED. The 5000K will probably be better but still have huge shifts. Probably no need to worry about it going too “warm” after dedome. Seems unlikely at any decent current.
I wonder where did Astrolux get the NW sst-40
they do not look like real SST-40s
bond wire pads are different
also the dots are not in square pattern
Die seems to be a tiny bit smaller
Phosphor edge is different, also phosphor itself looks different
That looks at least interesting, if it is not a real SST-40 then at least the forger did its best to make it look like one, if it is a real one then Luminus made a new die for it.
as it seems Astrolux can not source any more 5000K LEDs my thought is it may a very old die, different from any now sold ones
So I tried a N5 BC (Voltage: VH) in my M21A. My LD-A4 driver in the light was ordered with 8-12 Amp range so I set it to the bare minimum. Tail current was measured at 7.94A and voltage across the LED at 3.446V. It’s obviously bright AF, quite close to the sliced dome 3V XHP50.2 that it replaced.
The XHP50.2 measured 3.226V across the LED and the MOSFET probably took a hammering and caused the driver to overheat the whole time.
I will have to replace the LD-A4 with a LD-B4 driver and the corresponding PCB to combat the hot MOSFET. But I need some advice…….
Will it be OK to run the SST-40 at 8A? Or should I dial it down to 7A? The light is being used as a tactical light with high to low modes, no mode memory. So it always starts in turbo.