Order placed. Can’t wait to get mine!!
I’m not too familiar with the Zebralight/cpfselfbuilt lumen scale.
DB Custom, Robo819, Richard at MTN and Tom E use the Manxbuggy1’s lumen tubes which I think are only 10% to 15% higher than Maukka’s readings. (certain throwy lights might be a bit higher due to no diffusers in the design)
Texas_Ace’s personal lumen tube did read a bit higher than the ones above. About 30% higher than Maukka’s. After getting some reference lights shipped to Maukka to test, he has adjusted his tube down to match. All of the Texas_Ace Lumen Tubes he sold have also been adjusted down to match. Officially he still states about a plus or minus 7% range on them.
Maukka has also decided to sell a small batch of carefully measured and documented lights for anyone who wishes to calibrate their own integrating sphere/lumen tube.
I think the bottom line is if you want exact lumen numbers your gonna have to buy a $10,000 professional integrating sphere.
If you don’t want to spend that much money, you can ship a certain light to be tested by someone who does have one. This is slow and can get very expensive the more lights that need to be sent.
The next cheapest method is to just build your own device then calibrate it with a certified light from someone like Maukka.
The cheapest and probably best way is to just buy a Texas_Ace Lumen tube. It’s already calibrated plus is very well thought out. Plus you get lumen readings right off the lux meter with no math involved.
The two homemade options are always going to have bigger tolerances, but they are much more practical and cheaper.
As an addition to ToyKeppers post above:
The djozz-lumen is the output of my Sunwayman D40A on high setting divided by 550. It was established a few years ago and I keep it as my standard because it is consistent over all my measurements, and with the D40A always available it is easy to maintain.
Since then I have learned that the djozz-lumen is likely higher than the real lumen, some comparisons that I did in Germany with flashlights measured before in the LedLenser sphere, and an exchange of 2 different flashlights with maukka suggest that the djozz-lumen is on average around 9% high. But compared to maukka’s setup a high CRI 4000K flashlight (the 348 light that maukka is selling now for calibration) produced a bigger difference (11) than a 5000K 70CRI Nitecore P12 (7), so despite using a very high quality well V-lambda corrected luxmeter I have a spectrum sensitivity difference with maukka as well.
And lots of people think it’s easy to measure lumens. Just buy a lumen meter on ebay, they say. :person_facepalming: It’s funny.
I think the general consensus is that warmer tints do read a bit lower in lux compared to cooler tints, but this is still debated. I try not to think too much about it. It makes my head hurt. Lol
I’ve considered buying a calibration source from maukka. Before doing that though, I’d need to build a more proper integrating sphere… and I’m not sure I care enough to do that.
So I have a very cheap and compact measurement device with calibration based on a couple Zebralight SC52s, selfbuilt’s reviews, and a few people who were publishing numbers on BLF a few years ago. And it almost certainly reads between 10% and 50% higher than an ANSI lumen.
The downside is that it’s known to be skewed. The upside is that it typically matches most manufacturers’ published specs pretty closely. But then, another downside is that, apparently, most manufacturers exaggerate. 
Also, since what I’m using is small, it can’t handle more than about 2500 lm without some sort of attenuator. So I get to mess with neutral density filters while measuring bright lights.
But back on topic, it’ll be interesting to see how the GT-Mini performs. It seems like it’ll be a D1S with a nicer host, flatter but slightly lower output, and a more full-featured UI.
Have you considered getting a TA Lumen Tube? When you add up the time and parts cost to build a device that properly diffuses both floody and throwy lights plus an additional $75 for the calibration lights, you actually come out ahead just buying his for about $150 shipped. It’s well thought out and very easy to use. You don’t even need a calculator. 
You can have my HP48GX when you pry it from my cold, dead hands.
…
Well, okay, actually it pretty much just sits in a box and I use Python to do calculations. But still.
Sooooooooooooo much better
yes that looks alot better, but what about the frontal below the button what will be there?
Probably nothing.
The new font is better than the old one, but I still wish the logo was smaller.
well i dont see why not it cant have the logo atleast ? but a step in the right direction tho.
Do we have an estimate on when the first units are supposed to start shipping? I kinda want to see beamshots of both tints before placing my order. I would have preferred a 5000k option, so I’m not sure which one will be closer to my preferences.
Should be easy enough to change if the tint doesn’t suit you, I just ordered some Samsung LH351D in 5000K at 80CRI for less than $2 apiece bare.
Ordered a NW version with additional short tube, and 30Q since I only have 2 of these
if i remember correct, early next week for us that buy the light in here.
that's correct
the groupbuy people had this one week presale so they can Shipp as soon as possible
Ordered 1 Mini GT with 18350/18350 Tube.
Just filled out the form, is the GB still on Martin?
About the driver: is it sure a buck driver, as mentioned in this thread? I can’t believe they went for that, the voltage difference between a 18650 cell and a XP-L Hi is so small that it will only regulate current a little in the first few minutes, I’d choose for simple cheap lineair and have that extra boost of direct drive in those minutes. I’m curious about the first pictures of the driver.
Looking at Texas Ace’s measurements, the XP-L HI has a V_f of around 3.7V @ 4.5A.
So accounting for the voltage sag under load, a high drain cell should stay in the regulated region for slightly less than half of its capacity on turbo.
The other big advantage of a regulated buck driver over a FET is improved efficiency in the intermediate modes. So it should be able to produce noticeably better runtimes at 60-80% of max than the Emisar D1S. I’ll gladly take that over an extra 100 turbo lumens that won’t be noticeable by the eye anyway.
I answer todays requests tonight
will also add a Diffusor and a surprise ;)