If that TK61 was de-domed, figure I'd measure 530-550 kcd or so at 5m, and would probably be over 600 kcd if measured properly, at like 15m like rdrfronty does.
If I get a chance hopefully soon I'll be able to report on amps, lumens and throw measurements on a TK75 resistor modded. I'll probably go right to the R100 and R082 resistors, or maybe two R082 for a little more of a bump... 
I'm hoping/assuming the TK75 will behave like the TK61...
I would also like to bump up my tk75
The reason I went with the R015 is because it was recommended to me by someone very respected in the flashlight community who sells/mods a badass tk75 
I tried to push it harder then he does with a R010 but it messes with the UI and turbo/high become the same. With the R015 the UI remains fully functional and I was getting around 4.68A with the efests 25A but they needed to be charged. I’ll remeasure when I charge the batteries!
Cant wait! please report back 
So you are just piggybacking one R015? There is only one guy who sells/mods TK75's as far as I know...
Yup just piggy back one R015.
Guys, i think i’m totally confused, i tought the TK 75 can be modded to 7A per led lol, and vn mod it to around 3.8A or something similar…i guess 7A is huge and not safe at all. What would be the maximum you guys would go? i aim for 4000 - 4500lm (if not too much) from the 2900lm version, thanks.
Since it's a boost driver and all LEDs are wired in series, they all get the total amps output from the driver, it's not divided between LEDs as in a parallel-wired setup. 4.5A should easily put it over 4000L.
Thanks! i guess 4.5A is not too much right? maybe even try 5A lol? 
Sorry’ electronics are not my strong side.
Hmm, assuming is 4.5A thats like 2A less then the Panas 3400 mah protected can take right, so its all good no need for Keep-power or something with higher DR?
A boost driver works by taking a low voltage/high current from the battery, and converts it to a higher voltage/lower current output. So this requires some math.
First of all, to get 4.5A through a XML2 takes around 3.7v, so if you string 3 of them in series and want to shove 4.5A through them it'll require 11.1v. But your input voltage is a max of only 8.4v (it will never actually be that high unless the light is switched off), and a minimum of 6v. To get 11.1v from a 8v input requires more input current than output current.
Convert everything to watts and it starts to make sense.
We know the output volts/amps, and the input volts, what we need to find is the input amps.
The output is 4.5 amps at 11.1 volts. 4.5 x 11.1 = 49.95 watts.
Let's assume the driver is 90% efficient. It could be higher than that, it's unlikely to be lower. 49.95 divided by .9 = 55.5 watts input required to do 4.5A@11.1v output. Divide that input watts by the input voltage, and it gives you the input amps required.
At an input voltage of 8.2, the input current will be 6.76 amps. Since there are two parallel sets of two cells in series, that input current will be split evenly between the two parallel sets, so each cell will have to deliver 3.38 amps. No problem there, but it gets worse...
At 7.5v, input current goes up to 7.4 amps, 3.7A per cell.
7v = 7.92A, or 3.96A each.
6.5v = 8.53A, or 4.26A each.
And when it gets to the very end with the cells flat at 6v input, the current is 9.25A, or 4.62A each.
Getting the max amps with these lights all depends on the driver. Push it too much, and mode selection could stop working, or other issues, etc. Replacing the driver is not a good option - no custom driver or stock driver exists to do what the stock driver does in this form factor, that can be driven at extremely high amps. Someone has to do the research to determine the highest amps you can get, and have the driver still functioning properly.
Using Pana 3400's, you probably won't get as high amps out of it. Pana 3400's have relatively high resistance. Some drivers actually take more amps from the higher resistance cells to drive the LED's at the same amps, so, the extra runtime you get with 3400's is cancelled out. Again, all depends on the driver.
before you do any mod… go ask yourself are you willing to take a risk? if you mess up this driver, I highly doubt it FENIX will sell just the driver by itself. Just do a simple mod like TOM did should be more than enough… beside your eyes can’t see farther than the light can shine in the dark anyway :bigsmile:
I have tried many combinations of resistors on this light, along with bridging, and 4.3-4.5A is as much as possible. Bridging didn’t raise output, but did cause the light to lose modes. My suggestion would be to use Tom’s resistor combo. My particular TK 75 went from 107kcd stock to 134kcd, with the current bump.
Thanks alot guys, that explains it a bit better, great posts
Will report back once my friend do the mod for me
So I thought I screwed up the driver…… The stock sense resistors must of been damaged from soldering so many times while testing different combinations. Have you guys ever had a resistor do that? I have an R015 and R082 on there now but I just ordered some replacement R050.
Yes, too much heat will kill them, easy to do when hand soldering.
edit: Three R082s (0.027333) would come pretty close to matching the two original R050s (0.025).
I only have one R082. I wish there was a 1206 sense resistor kit from .001-.5 ohm. I hate ordering them as I need them but i am slowly building my stock lol