Just got my MK37vn in from Vinh. As far as I know all he does is a delid of the SBT90.2, which improves output and throw by ~5-7%.
First thing first is, the knurling on the tailcap and body is really rugged! Almost too sharp and course, but definitely very grippy. It digs into your skin quite well— good or bad. Overall size and heft, plus not being top heavy from a big head makes the light feel very nice in the hand, though.
The beam profile is more reflector like than I thought, and it’s like a narrow+deep reflector type beam profile, meaning smaller hotspot, and larger corona. There is definitely some spill, but not as noticeable as as a traditional reflector, because the edge of the spill is a little more diffuse than the hard edge of a reflector. Compared to the optics in my MF01/MT07, I can see noticeable spill. Compared to a traditional reflector, the spill isn’t anywhere as bright however, but still noticeable. So I wouldn’t say the output is almost entirely in the hotspot, because there’s definite spill this optic produces, but it’s a far-cry from reflector spill. One cool thing though, is you get very little off-angle glare as another person looking into the light compared to a traditional reflector, because of the way the optic is designed. There is also a ring around my corona as well,. On the positive side, the light seems very well focused, and there’s distinct pedal shapes on the corona itself, that are equally spaced out and sized, meaning great centering.
Comparing turbo burst to the MT07, which is modded to have 7 White 2mms (cslpm1.tg), putting out 7700 lumens and 115kcd (Vinh’s measurements), to the MK37, which has 1 sbt90.2, outputting 5100 lumens and 252kcd. The 1 sbt90.2 in the larger, beefier MK37 body gets hot much faster, and is almost too hot to touch at the heatsinks at around 30-40 seconds. The 7 White2s in the MT07 stay cooler longer. This makes the turbo on the MK37 purely a burst feature, and only useful for 30seconds to 1 minute at a time unless in freezing conditions, and that would only probably extend that runtime by mere seconds. The SBT90.2 is such a power-hungry LED, I just don’t think it’s a sensical choice for any host that’s under the size of say, a BLF-GT. If manker’s numbers are to be believed, however, and if the light can sustain constant output at 1100 lumens while achieving 40kcd, that seems to be the sweet spot for this light.
The UI was a bit disappointing to me. On paper it reads fine, but I really miss the option to cycle to regular output levels from a long press from off. From Anduril or Zebralight UIs, you can long press from off to enter moonlight, or the lowest mode, and keep it held down to progress in brightness. Doing so on the Manker leaves you on moonlight cycling purgatory. Double click from off or while on still gives turbo however, which is very welcome.
These are all initial impressions without outdoor use, but so far they’re mixed, mostly due to UI and beam profile. (I knew what I was getting into with the SBT90.2’s heat output based on my experience with the Acebeam K75.).
I can’t wait to take this outside and let it shine! I will also do a runtime test with the 1100 lumen mode to see if it can handle the heat.
Edit: doing the runtime test at 1100 lumen setting, and the light is only warm after 15 minutes, and output seems to have stayed the same over that amount of time, so having 1100 lumens and 40kcd that seems very sustainable in something the size of the MK37 is really nice!
