I did end up reaching out to Simon who said my order was for the 6500k. I’m about 95% sure I ordered the 5000k but oh well. Oddly enough my order confirmation email doesn’t list a CCT for the SFT-25 while the other emitters I ordered do have the CCT listed. Simon did tell me that the bin he stocks for the 5000k is DD and the bin for the 6500k is BA.
In the end I guess the takeaway is don’t use my data for info on the 5000k version.
Yeah, I figured yours was an outlier when I got my 5000k SFT-25R S6 from Simon and it was nothing like the one you received, I highly recommend the 5000k though, Simon has a really good bin on it, and if I’m reading the datasheet correctly there isn’t a reduction in brightness between the 6500k and 5000k within the same flux bin.
You should be able to see order details in your account on the Convoy’s site.
No CCT listed there either, only the MCPCB size. Strange.
Glad to hear the 5000k is good, time to start putting together another order I guess. I’m still impressed with the emitter overall despite the very blue CCT.
Interesting…I bought a 5000K version from Simon and it goes very blue at 100% on the 8.0A driver; like it’s normal for a fraction of a second and then suddenly turns blue. Color is very similar to your photo.
It doesn’t do that on lower modes; in my experience that indicates over driving.
I don’t think heatsink or reflow were factors, since I had it in a Convoy L21b with good thermal grease.
So, I moved it to a Convoy M1 18350 host with a 5.0A driver and it behaves more normally; good pocket thrower.
This is a very interesting observation–I wish there were a test of the 5000K.
I agree that it is indication that 8A overdrives the 5000K SFT25R. I suspect that higher CCT variants are also overdriven at this current, but perhaps nobody notices it due to the same amount of CCT shift being less noticeable (shorter Euclidean distance on the CIE1931 diagram) on the upper end of CCT.
So I just got an sft25 6500k in an S6 with 8A driver and it has some egg yolk in the hotspot.
Next time I’m doing some mods I may switch it with some of the first batch of sft25’s I got from Simon when he first offered them. They were better.
My S6 SFT-25R 5000K 5A also has significant tint shift in the hotspot.
Seems like there might be an issue with the uniformity of phosphor deposition. One Nichia 144a sample, tested by djozz, has it bad:
I got 4 of the 5000ks from Simon and put them in a s21A quad i built. With a resistor modded 6A driver, BeCu tail spring from Mtn, driver spring bypass (running at a hair under 13A at the tail with P42A, so 3A for each led) the tint is really nice and neutral. A bit greenish at low current, but 20% and and up it’s nice. The - led wire separated from the driver, so it’s currently out of action, but will send beam photos comparing a 5000k xp-l Hi and the sft25r 5000k and 6500k.
A shame that Luminus does not seem able to fix this annoying tintshift with rising current for the cool white ones.
These LEDs would be so good, if this wouldn’t be the issue.
Yah it’s a Luminus thing. All their leds even the FA sst20s were green at low output (some worse than others). I think they will get it right eventually.
This is my hope for more than two years now.
Nothing has changed since then. And this problem was also known from the old SST-40 from 2017/2018, so they haven’t fixed it. But since the Luminus LEDs are selling like hot cakes, why change it? That will probably be the ulterior motive of the people at Sanan/Luminus.
