What light is that with the Red LEDs?
This one:
Also available in 18350, but not in blue:
Same drivers, normal modes: Lo, mid1, mid2, high
hidden: turbo, strobe, SOS, red light and red blinky
1 Thank
I’ve had a Speras M4 for a while- it doesn’t get used much. The stock LED is a Yinding 5050 (or it looks identical) and a horrid green colour at low levels. It’s got a good throw for the size, but for general use you need to have it turned up to get any spill e.g. walking in the dark. I was going to swap a SFT25R in, but when I pulled it apart I discovered a custom MCPCB that is larger than 20mm diameter and has three locating lugs for the TIR.
So that plan was scrapped as there’s no way to fit a 3535. I looked online and noticed the latest model has an SFT40 fitted- so I used the stock MCPCB and put an SFT40 onto it. Stock, they have the short body and use a protected 18350 battery- with warnings to only use protected cells etc. I’ve got the optional extension tube to enable 18650 use, so after doing the emitter swap I fitted the extension and charged up a (unprotected) VTC6 18650.
The output is way better than I expected. I measured the tail cap amps on turbo and it’s getting to over 8 Amps! Needless to say it works rather well now and also has some useful spill to the beam at lower levels.
If you’ve got the original Yinding version it’s a mod worth doing. BTW I used some double sided tape to get the “stuck” TIR out. It looks like they glue the legs into the MCPCB.
4 Thanks
I had a convoy S21A triple with an LD-B4 driver that I never really used as I didn’t like the luxeon V emitters in it (though they did make lot of light!). I was going to order some CULPM1 emitters for it as it had a 4040 MCPCB but they are pretty expensive! So instead I dug out one of my last 3x 3535 Led4power MosX boards with the FET & NTC attached, reflowed some old gen 1 XPL-HI 4000k emitters from kaidomain and put it all back together. Now I love it! Its got a lovely rosy tint, though the low cri does make wood & skin look a little odd.
A side note: I love the “LD-B4” solder mask markings on the solder pad for the spring, the solder avoids it leaving some very cool text swimming in the solder.
(Yes I cleaned the flux after these pics, no solder joints were harmed in the making of this 
)
P.S. Anyone know if the Fireflies 4000K 3535 domeless emitters can be FET driven? I’m tempted to try and fix that low CRI…
2 Thanks
Some of my favorite 4000K emitters!
Rip L4P 
2 Thanks
Pre-covid my flashaolic friend order from Hank a KR4 TiCu coloured with XPL-HI 4000 or 4500… they had the same tint of SW45. For me one the best emitter on the planet.
Very neutral without green and rosy tint.
When I order my first D4V2 with the same emitter Hank send me the new batch…
I do a lot of research of those XPL but I never found it in any way.
1 Thank
I put hot chili powder in my noodle soup…
3 Thanks
Hmm interesting, I’ve a 4* Luxeon V MCPCB from Led4Power in my BLF Q8 but have been casually browsing possible upgrades, this might be the solution…
9 Thanks
Mmmm egg yolk yellow looks tasty!
1 Thank
I really enjoy seeing people put new emitters into old lights!
The old Fenix TK series is really iconic in my opinion, Fenix were making some really innovative stuff at this time.
1 Thank
Same! I tried the luxeon V and the 3V xhp50.2 in my Q8 and they were both quite floody. Ended up putting some 5000K sft40 in it and now its got some throw as well
1 Thank
Nice that you made an old flashlight fun again. 
I’m also impressed that 1 of the black wires is soldered directly to the aluminum shelf!
Oh, i’m also modified a first light in TK series - T1 . A little bit of turning on the body of the flashlight and now it uses a 20mm star with a nichia 519a and 18650 . I also replaced a few components on the original 2007 driver and it now puts out about 700 lumens.
3 Thanks
Not exactly. There is a brass contact pad to which the wire is soldered and screwed in place
Ahh, that makes more sense. I can see that now and that would explain the purpose of the screw.
Pink/chartreuse/ice blue aux lights in a KR1. This is a similar setup to the D1 I did a few weeks ago. I used Loneoceans aux board and a Ledil Olga M TiR.
The chartreuse is a bit strong. So I’ll be changing the resistor on that.
Watching the lights dance under those optics is a bit mesmerizing.
3 Thanks