BLF GT (preliminary) modding thread

After some more focus tuning and final assembly, at 20 meters, my modded GT measured at 3,508,000 lux! Super!!

(Beamshots next!)

Not bad at all, makes me want to give it a try. With that new “flat black” that has a neutral thermal pad, it would be far easier now. Could even use the stock driver I think with a minor mod.

What driver are you using?

I’m using Lexel’s BLF GT Oslon driver set at 4.5 amp max. In the case of the GT, the neutral thermal pad is not a big advantage because the light body is not used for the return.


Modded GT

The Sceptre

In person, the beam from the GT appears to go farther. It’s quite impressive.

pscal….very awesome mod! I love it! I was pretty happy with my GT until I read over your mods. Now I’m gonna end up cracking my open before long. Thanks a lot! :wink:

Oh, I would love to see some beamshots of a water tower or building from some distance. Would be even better to compare with a stock GT.

Thanks! I no longer have a stock GT for comparison - best I can do is an MF04s. Getting beamshots is also challenging for me right now because I have a toddler and an infant that dominate the night hours. But, if I can get away, I’ll try to get some shots worthy of this GT.

pscal’s aspheric builds are right up there with deft-x quality, but with 3x more lux, great job :smiley:

I haven’t seen another video about how to open the GT. So I hope you find it useful.

Lucky fellow. Usually the head breaks loose before the bezel, or did you have to reef (tighten the living hell out of) the head first :smiley:

I don’t bother with the bezel anymore, just removing the head get’s me to the area I need to make changes too. Less chance of crap falling into the reflector, specially from the loctite bits from the bezel, if I need to shim the reflector on the XHP35HI GT, then I just break the bezel loose, I don’t remove it, that way I can tighten the head with out all that added pressure on the lens.

Can someone point me to a thread on changing the XHP35 HI version to the XHP70.2? Would like to know the process for my BLF GT

Have you ever changed a driver or led? That’s all you basically do.

Check VOB’s video here.

Has anyone found an in-stock supply of XHP35.2 HI in flux bins greater than D4? I hope to find E2 flux bins or greater in 5000-6500K to reflow into my stock GT. Crees data sheets appear to be dated and they are notorious for not listing all available variations. I’ll probably settle for a D4 if nothing turns up. Mouser has plenty in stock and they are easy to deal with.

Still no listings showing for XHP70D-H0 variations (XHP70.3 HI). Id love to try one in a GT with a TA driver, assuming high flux bins once available. Cree’s data sheet looks promising.

I’ll probably cross post this in a few other threads to see if anything turns up…

Dredging up this lovely thread as the glue dries on my latest GT mod.

It seems like every time I acquire a BLF GT, it’s only a matter of time until I succumb to the aspheric devil on my left shoulder.

My latest acquisition started out as an original BLF GT. I upgraded it to a BLF GT90 with a Lumintop BLF GT90 driver, an SBT90.2 on a Noctigon 32mm MCPCB, and parallel battery carriers from JLCPCB. In doing so, I also upgraded the springs in the carriers to BeCu, including the top contact springs, which I also improved with a larger screw head that touches the brass contact at just the right spot to bypass the spring.

The 32mm Noctigon MCPCB underside had to be filed to allow clearance for the 16awg wires. I finished it off with a 3d printed GITD centering ring and proceeded to shelf light for a few months.

Since my original GT aspheric mods, I’ve picked up a 3d printer. For this mod, instead of using PVC bits, I designed and 3d printed the necessary parts for aspheric conversion. I found this solution to yield a superior end product compared to the PVC in terms of functionality and fitment.

-Bottom lens retaining ring

This is a ~30mm tall ring that slides into the head of the GT to support the lens from below. It friction fits into the head and has a recessed area that precisely centers the lens within the head. Its height is precisely set to place the SBT90.2 at the focal point of the lens.

-Top lens retaining ring

This ring goes on top of the lens and retains it from above in combination with the stock GT bezel. It is chamfered to hold the lens tightly.

-LED retainer / Wavien collar spacer

This piece is designed to precisely locate the 32mm Noctigon MCPCB and utilize the stock GT mounting screws. It also serves as the spacer for focusing the Wavien collar over the SBT90.2 (1.3mm on my particular printer.) This piece underwent several revisions to ensure excellent fitment and functionality.

Finally, the Wavien collar was attached with shoe goo to the retainer/spacer using my HDMI microscope. The solder joints needed to be flattened to <1.3mm tall so as not to interfere with the collar.

Once the glue holding the collar cures, I’ll measure it.

This is my very last Wavien collar and this light is the pinnacle of my flashlight modding hobby in terms of performance and fit & finish, so it holds a lot of value to me. With that said, if you really need this light in your life, I may sell it for the right price.

Well done! I hope you’re able to focus the beam. Looking forward to beam shots and performance figures.

Thanks! A quick 20 meter measurement yielded 3,320,000 lux. I am stoked.

Very nice! Be careful you dont burn a hole thought something with it!

You left the glass on the 90.2?

Yup, for now at least. I had to do a fair bit of fiddling with the MCPCB during prototyping, and I use flux every time I solder the leads. The glass was definitely helpful for that process. How much would I potentially gain by removing the glass?

About 5% is what I’ve seen people report, but maybe with the retroreflector it would be even higher because the light is passing through the window more than once, and also because of the angles involved in the transmission.

Hi guys,

Back on BLF, mostly lurking for now, catching up on the developments of the past 2.5 years or so.

So i have one of the earlier GT’s here, i almost forgot i had it at some point.
I think i only used it a few times during a couple of weeks in France.
The XHP35 it came with never really impressed me much.
So i’m wondering if i should beef up the stock driver and get an XHP70.3 HI in there or get an SBT90.2 and a buck driver from Simon.
Any thoughts?

My opinion: Both options are vastly superior to the original XHP35.

XHP70.3 HI if you want a larger more useful hotspot and the possibility of warmer color temperatures.

SBT90.2 for achieving the best throw number.

Update on my aspheric GT90. I upped the LED wires to 2x16awg teflon insulated, and de-lensed the SBT90.2 I also used B7000 glue for the Wavien collar instead of Shoe Goo. It seems to work great so far. Hopefully it will come off clean if needed.

This light now measures over 4 million lux (measured 10,500 at 20 meters.) That far exceeded my expectations. I measured twice to be sure, and will do it again with an assistant, fairly soon.