µReview in Post 3
Tagchen!
I just got the JKK36 from KD
I love the formfactor and the USB-Output and charging - but the beam has a massive donut-hole.
Will that vanish when I change the LED with an 70.2?
Also, the light colour is more like 4000k than 5000k
Thanks!
No idea to your question but can you upload a photo of the beam with the donut hole?
Had this light on my list to buy. Thanks mate
Sure 
µReview:
The LED is on Copper and well centered, the reflector and the glass look very good.
overall machining is pretty decent.
The light gets warm soon enough
I charged some 26F in the light and measured them afterwards - 4.21V
since my cells were nearly full (4.15V), I cannot tell you the charging current.
The USB-Output:
Idle: 5.14V
2.14A - 4.85V
2.44A - 4.62V
2.55A - 4.50V
2.70A - 4.31V
I like lights that are a bit thicker and this light is friggin awesome - if the donut wouldn’t be there 
I would say - If you don’t mind the donut, you get a fantastic little light with a lot of functionality.
You can try putting the reflector closer to the LED board, should solve it.
the reflector is pretty much directly on the board - the spacer is just a ~0.1mm thick sticker around the led to protect the traces from the reflector 
Thanks for the photo and mini review.
My Maxtoch M12 XHP70 light has a worse donut hole. At about 15 metres onto a wall and you can still see it. It really bothered me at the start. Not so much anymore.
I think I can live with the JKK36 donut hole haha
textured reflector should not have a donut hole like that. from the picture the emitter is well centered. Perhaps change a thicker spacer can make the beam nicer.
I think O-L had said that the donut hole with XHP70 was really bad, and he couldn’t get rid of it on lights he modded/built. Perhaps changing to XHP70.2 will help with that.
That’s not that Bad, I have seen way worse! 
I have a few lights that I run the 70 in with huge smooth reflectors.
Like the TN42 XHP70 P2-1C I don’t mind the artifact because of the amount of Boom this thing puts out!
You can shim the reflector up, frost the dome or shave it and frost it, if it still bothers you?
Just make sure the dome/silicone is perfectly clean, maybe fire it up a few times to make sure before putting the reflector back in.
But to answer your question the 70.2 still has the artifact (quad die) but it is barely seen with an OP reflector and just visibly seen with a smooth. It is alot better then the Old 70.
I put the 70.2 P2-3B 5000k emitter in a SR90 with that huge bowl of a reflector and it’s going to stay, it’s that nice of a beam, that and I’m tired of messing with it!
I also have the 70.2 P2-1A in a Jax X6 Hunter, and I run the Convoy L6 Smooth and Op reflector in it, and the OP reflector makes for a really nice smooth floody beam, very little if any visible artifact to the untrained eye. I can still tell its there, most people haven’t any idea, that I have showed it off too!
This is with the smooth L6 reflector in the X6 Hunter, I like the added bit of throw!
I can still see the quad die artifact, but again it is not that pronounced as the old 70.
Yes the XHP70.2 will help a lot.
Just ordered the 70.2 on DTP in 5000K:
http://kaidomain.com/p/S026865.Cree-XHP70_2-Neutral-White-5000K-LED-Emitter-with-20mm-x-1_5mm-DTP-Copper-MCPCB-6V-
Reason: Today I got the [KDIY K5](http://kaidomain.com/p/S026765.KDIY-K5-Cree-XHP50_2-Neutral-White-5000K-2650-Lumens-5-Mode-LED-Flashlight-Black-(-1x26650) with a XHP50.2 and there is absolutely nothing what you could call a donut.
Just a very nice round beam.
Very nice light btw.
I just unscrewed the pill and put some thermal paste between it and the head.
That’s it. Otherwise an extremely nice flashlight with a lot of power.
I put an XHP70.2 P2 1A from KD in my JKK36 today, no more donut hole at all. All in all I really like the host, great heatainking, good size, and power bank function is a nice touch that I wish more big lights had. My only complaint is with the driver. Mode spacing is horrible with no real low mode, and the output is not fully regulated in any mode, so it will drop with battery voltage.
Yeah, the driver is a bit weird.
Although I don’t have a problem with a missing “real low” or moonlight - no memory and it starts on high, not in turbo, is not what I am used to.
but good to know that the donut hole is not more with the .2 - thanks!
You can double click from off to start in low mode as well.
Personally I do like to have good low modes, especially since I modded my driver, so my low is now probably about 1000 lumens with that XHP70.2 P2 1A emitter.
Please tell me more about this mod I need to do
That double click feature is new for me - thanks!
Just a simple sense resistor swap. The sense resistors are the little black things with white numbers next to the LED negative output. Stock the driver comes with 3 resistors in parallel, R082, R100, R500 for about R0413 net. I swapped in an R075 and R050 for a net R030. You can see all the output data here.
Alright - 3 0.1Ohm and one 0.36 Ohm should make 0.03Ohm.
Now, the Turbo-Mode is just a tiny bit brighter than high - the tiny cables?
I have 3 26F in the holder - they should be good enough for that.
I didn’t change out the cables because I want to wait until the new LED is here.
Stock mine had 24AWG, I put on 20AWG and shortened them quite a bit, the wire holes are probably good for 18AWG, but I didn’t have any on hand. I also bypassed all springs with 2x pieces of solder braid.
I have a noticeable increase with each mode, but it is not huge. Part of why I wish mode spacing was better. I am also using 3x NCR18650BD.
Just an update, the JKK36 is now available with 70.2 with SMO or OP reflector. Was turbo always 3800 lumen?
Another update. I have done driver mods that significantly improve the driver mode spacing, as well as give the light full output regulation over the entire discharge. Instructions and test results posted here.
I used a slightly different sense resistor config in the actual light compared to the test results to get 4.2A on turbo.