Thanks for the recommendation…sounds perfect :+1:
Also Mandrake50, for 2nd opinion :nerd_face:
ONE PROBLEM: Aliexpress only lists CCT “ranges” for the FC40……”4000k-4500k” OR “5000k-5500k”.
If you recommended “4500k”, would it likely still be safe to order “4000k-4500k”, or too chancy I’ll get a “yellowish” one? Or, just get that one and be done?
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The one I have was listed 4000K-4500K. I am sure that there can be variances, but I have seen few complaints for this one… or really for any GT-FC40.
Awesome….thanks! :+1:
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Agreed w/ Mandrake50. I have both, Getian GT-FC40 “4000-4500” (measured 4500) and “5000-5500” (measured 5300). Like both but the GT-FC40 4500k is most definitely the one to buy for me.
I have great news regarding the 519a LED’s in S21F. In subjective testing during evening walks S21F is killing my Wurkkos TS21 w/ Nichia 219c 5000k (which I had liked very much), so I asked Simon for R9 number for the LEDs (Ra I already knew is 98). He previously would show me actual measurement but this time just gave me the spec, probably because he didn’t have one on hand.
And per Simon, R9 is > 80. This means the 519a LED’s in S21F has the highest possible rating, R9080 . Not bad for a $30 light, with Buck driver. Partly why I don’t complain too much when it comes to Convoy lights. 
Another interesting discovery about S21F. There are 2 ways to reach around 3500k CCT:
1. By double click and hold to ramp the CCT to 3500k. The advantage of this mode is you could adjust outputs to the 4 brightness levels. The disadvantage is it has lower max output @ 900 lm, AND there’s PWM (if this is considered not desirable - I don’t know for this case).
2. By double click from any mode to Turbo 5/5 mode. At 2000 lm, this mode has the highest output of any of my small Nichia lights. It also has among highest sustained output @ 680. AND, surprise, same CCT as above, but no PWM .
Whatever the algorithm of S21F’s CCT ramping, this S21F has highest output AND no PWM at 3 points: either extreme end, 2700k or 5000k, or True Turbo 3600k in the middle. And no PWM, even when stepdown kicks in.
Y’all recommend FC40 over 70.3 90cri?
How’s the tint lottery on the FC40?
Having to do this kind of thing to get it to where I want it would drive me crazy.
Sticking with my 4500K S21Ds, as they’re the CCT I want 100% of the time, with no extra effort on my part.
The beauty of the S21F is the ability to change temps and the 4500k on the S21F will look different than the 4500k on the S21D.
Does the FC or BAM have better tint?
If I 1) don’t want to change temps because I already know my preference and 2) don’t want it to look different than the S21D 4500K, there’s no logical reason for me to purchase one.
. nice question. I have simply decided to have one of each.:
–219b 4500K in the S21D,
–519a 5000k in the Wurkkos FC11 and also 3500K in the Convoy H1
-GT FC40 4000K in Convoy S11,
-B35AM — I think I will now order either in the S11 or M21B.
For under $150, I will be able to answer that for myself! Only missing E21a but I’m not that compulsive, and I think the E21a ship last left the dock a couple of years ago.
Would like to hear your thoughts once the B35AM arrives home, I also have one on the way but have yet to try the FC40
I hesitate very much to say any LED has “better” tint than any other because this is (obviously) personal preference. No right or wrong. I think that’s one reason why this is such a fun hobby: all the lights are different, all have pluses and minuses.
Re. FC40 vs BAM: 2 very different LEDs. FC40 4500k leans towards 519a 4500k as being more sunset-yellow, whereas BAM leans towards 219b 4500k as being more rosy. (Nothing I have equals the rosy/magenta tint of 219b 4500k, or make colors pop like it. But again that does not mean it’s the most beautiful or best for everyone.)
Besides tint, FC40 @ ~ 2200 lm is twice the output of BAM ~1100 lm. In same host, Convoy M21B, FC40 is medium floody/throwy whereas BAM being a smaller LED is very throwy. These last two parameters make FC40 “better” as EDC, especially for muggles. Of course BAM has the highest Ra and R9 rating I’ve seen, but that’s important only to “collectors.” All IMvHO.
I don’t think anyone knows….Chinese manufacturer and they haven’t made much of anything available (not publicly anyway). You might read through the initial thread when rngwn discovered them a few years back (and a couple others linked). I don’t know if anyone has been able to get a data sheet or any solid info about binning/groups. If Simon was able to, it might be buried in his main thread here.
WTS/GB: [4000k ARRIVED, Test Report's In] GT-FC40 (a.k.a. XHP70's flattop, 12v 40w sister) 95 CRI, Available in 4000k, 5000k (Maukka and djozz tests linked)
Generally above BBL. I haven’t seen beamshots that look “nice” at lower outputs but it’s not bad with more juice.
Mfr page for the family although they still have not updated it to show the FC40: 30W COB LED, flip chip led, led with copper base
When I got my first GT-FC40 light, I knew I had struck gold when during photo processing, I had a some difficulty telling which shot is GT-FC40 and which is 219b 4500k, for the 2 pictures on the left side. (Same cannot be said of the green SST20 and extreme green Cree XHP35-HI.)
Once I knew to look for certain clues, then it’s easier. In some way, I actually prefer the color rendering of GT-FC40.
At this level of Nichia vs GT-FC40, IMHO they are all different from each other, not necessarily any one is better. All excellent and I am thankful for Convoy’s 30 buck a light policy 
that makes buying them so easy.
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S21F back in stock for ordering @AliX 
In for 2….one as a present 
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@Erion929: Might be late but if you don’t have S21D yet, maybe one S21D and one S21F? That way you could see the difference?
S21D is brighter but can’t change CCT, S21F not as bright but can. Two different flavors. Just check with Simon if you do change your mind.
I’m hoping once more of these get into users’ hands that someone rips one open and posts pics of the driver. I’m really curious how he’s managed it to be an 8A buck driver and dual channel…
Scoped out the S21D for awhile for it’s CC driver, but for myself I always like ramping output vs. stepped….and for my Maglite brother, he needs the USB-C
The 21F seems to fit needs the best for a “mid-lumen” around-the-house light. I have others for bigger output/throw. Also, can’t dismiss the utility of….and experimenting with….ramping tint.
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Mid-lumen around the house, and you already got other lights with more output - you got it exactly. I know many people don’t always start with “Turbo” like me and S21F would be fine, but just thought I should “categorize” the 2 lights accordingly. With ramping output and ramping CCT, S21F sure is a fun light and the USB-C charging means I will use it more than S21D.
For better central brightness in S21F, you could switch the optic to 10 Bead or 30 Bead and see if you like that better. In actual use I don’t see severe artifact that would bother me with 10 Bead, though I should mention 60 Bead has the most beautiful (most rosy) and homogenous field.
IMHO, S21D maintains brightness at least partly, maybe wholly (?), because it has this “crazy aggressive” thermal regulation that keeps the light very hot, and hence bright. It runs about 10 C higher than S21F at any given point during simultaneous run-time check. For example 50 C external with S21D vs 40 C external with S21F.