The SFT-25(R) 5700K is available on KD. This emitter show the typical Luminus tint shift at different currents, with a slight yellow-green tint at low mode, though I personally find it acceptable. The beam intensity was measured at 5m using a phone as I did in my other previous posts. The stock CSLPM1 is around 40kcd, after swap is 52-58kcd.
Due to the reflector match and focal point, the mod resulted in a slightly “nested” hotspot and corona. So, even though it’s a round die, the beam profile isn’t as good looking as the stock rectangular emitter.
The reason I did this at first was just because I thought the low thermal resistance of SFT25 could reduce heat, but it didn’t seem to make any noticeable difference.
The modding process was painful.
You need to heat the head for a long time with a heat gun or torch lighter, and use two strap wrenches to unscrew the head. The MCPCB is a proprietary 19*2mm round copper board with 3030 pad. Actually, it’s not a typical 3030 pad, the electrode pads are dots rather than bars. Anyway, I accidentally scratched it while using solder wick, making it more like a regular pad.
As expect from Fenix, the dimension for the reflector and centering ring are also proprietary. The reflector sits tightly against the MCPCB, and the centering ring is a 6.x mm round cone. There’s a plastic ring on the MCPCB to prevent shorts caused by scratches during assembly.
The SFT25 footprint is 3535, and since the difference is minor, it can be soldered on. There were some old Reddit posts discussing whether a 4040 footprint could fit on a 3535 pad, and no one provided a clear answer. From my experience, slightly different footprints can be compatible, just make sure you have a multimeter to check for short circuits.
I bought some 3535 5mm gaskets from Convoy, due to the size difference, they serve as gaskets and cannot be used for centering. SFT25 is 0.2mm taller than CSLPM1, so to match the focal point as closely as possible, I grinded the gasket down to about that thickness and manually centered it by feel.
Thanks to the people who helped me in the process.
