Ordered an SST-20 4000K D4V2 brass. Not the best timing for me, but I don’t want to miss them again!
Are all of the mcpcb non DTP or just the E21A quad mcpcb?
Just the E21a are not DTP because the emitter does not have a cooling pad, just + and -. The others are DTP.
So even the 16xE21A is not DTP?
I do not think there is any possible way to make E21a MCPCBs DTP.
Is the board a solid copper/metal core though? Would hotplate work reflow work? I want to reflow some of my own E21A into a KR4 host.
What are the advantages of E21a?
The output seems so low. Something like 1/3 of the maximum output of XPL HI or even SST-20. It even sounds like less output than Nichia 219C.
Very high CRI and R9 values and consistently excellent tint, close to or under BBL.
Thanks.
I think this emitter isn’t for me. I’m not willing to settle for 1/3 the output just to get good tint and CRI. SST-20 is good enough for me. Especially if run at higher power and from the better bins.
With the quad E21a lights ive built, if i put a 10A cell into a light and activate the FET, i litterally get smoke off the emitters within 1 second.
They dont die that quick from that current, but im not game to play beyond 1-2 seconds of smoke 
The light off 5A is pretty good given the quality of the light. I also changed to a less floddy optic and sanded the top a little, its got a little more throw in it now.
Hey, brass light owners, how long before patina renders an EDC dirty looking?
I don’t yet have a brass light. The D4V2 brass looks pretty damn great when shiny.
E21A is a really nice emitter for people who prioritize the quality of light over the brightness, but it definitely won’t “wow” people on turbo like a lot of other lights do. That’s not what it’s about.
As for brass lights, the patina develops slower than on copper… and tends to go through phases. At first it starts getting darker, but eventually the dark areas sort of rub off to reveal a light dull matte shade. It’s okay, but for lights which have knurling or other similar features, handling it mostly just darkens the raised portions while the recessed areas stay shiny. I think that makes it look bad.
Instead, to really make it look nice, I’d suggest artificially forcing a patina, and then gently using a polishing cloth to shine up the raised portions while the recessed areas stay dark. And then polish it again once in a while when the shine wears off.
Don’t know much about spectra or the human eye, but the 3000K E21A light I own is just, well, wow. Very different to SST-20@3000K. Looks warm but still natural. Magic.
Yes, it’s nice to see Emisar stepping out a bit from the trend of “pocket rocket” with better light quality flashlights.
I would like to see an ordinary EDC light from Emisar. Not a pants-burning quad and not a pencil-beam thrower.
Received my KR4 E21A yesterday. I’m running it with the 18350 tube. It’s basically identical to my FW3A 219B sw45k. Slightly less rosy tint, still very nice.
What is the max ramp amperage for the KR4 E21A? It looks basically identical at top of ramp to my FW3A which is I believe 2.8A or so. 5A turbo looks the same as the FET turbo on my FW3A. I’m using a 35E with my FW3A 219b so probably not pulling too much more than 5A.
I’m honestly not sure why you would ever choose E21A over the old venerable 219b at this point… seems to have roughly the same output, similar tint, but it can handle even less current. I guess it is dedomed so would throw better, but not with the KR4 frosted optic.
Has anyone gotten 4500k like mine and swapped the frosted optic for clear? How bad is the tint shift?
Simple, E21A is still manufactured. 219b is not.
Also, E21A is great for tint mixing on a quadtrix board.
@Hank
Where are you hiding the KR4 16x E21A mules? I'm still waiting for those. 
Hello
Received my KR4 E21A today (cyan, 4500K). It’s looking very nice. 
I still have to test it in the dark. 
What cell do you recommend? I have Samsung 30Q, LiitoKala Lii-35A, maybe some other in other flashlights.
How much A does this FL needs?
Thank you
Kind regards
MoreLumens, I cannot describe it and my camera can’t catcht it: My eyes easily adapt to the E21A tint, but hardly to the SST20. There must be something special about it. Otoh, I made this a topic on TLF and no one seemd to understand what I mean. Maybe it’s just me.
Unfortunately don’t know the warm 219B. The sw45k however looks nice, but not natural to me. Other tints may do a good job in this regard. I’m sure Jon knows 
.