Got home today early for a change, after reading KevinL post about 35k led vs other leds in led section and some struggle deep within (for like, 5 minutes)--I had decided to mod the SF A2 Aviator into a hybird with 35k mcd leds.
The result is definitely satisfying and the process is fun(but part of it is a pain in the behind).
Swapping the leds in a SF A2 probably has been done and mentioned in the past, and the following is just some pictures and description of how a dummy do it
Update 23/9/05--I have finally decided to switch in the MJ uncut leds into the SF A2 led swap mod. The main reason behind this is the level of overdrive a led could take--if my calculation is correct, then the 35k or original leds are driven pretty hard at 78ma.
It might work well with the original leds, but there is an uncertainty about how much the 35k could take or how long will it last at that level.
For me, since this light will become part of my EDC inventory, though the 35k is truly amazing in terms of its very tight concentrated beam, I cannot bear this uncertainty/risk that these leds' output might diminish over time(or in a short frame of time).
Thus, I have decided to swap in the MJ uncut leds for the SF A2, which is more floodish but just about as bright. More pictures at the end.
First, unscrew the led ring from the bezel. Slowly wiggle the led ring out.
The led ring without the anode ring. This is the only painful part of the whole process, to undo the anode contact ring from the led ring. I have so much respect for the SF quality of work, even for a small piece, it is well designed and so securely attached together.
This is the anode ring that has been taken off the led ring. You probably have to take it out to mod the leds properly. The trick is to use a solder wick to absorb all the solder off where it is connecting the anode ring and led ring. Then put the solder iron on top of the little tab and wiggle it loose from where it is...finally use a real sharp knife to slowly pill the anode ring off the led ring while heating it up with a solder iron. Be very careful since both the layout of led ring and the anode ring are both quite delicate. If you destroyed either one or damaged it too badly, there is no turning back!!
Another easier route could be done if you just snap the legs of the original leds and solder the new one on top...but you'd better be lightning quick, since there is hardly any solder connecting the leds to the led ring.
Swapping the leds in process. I have measured the three little SMD resistors mounted before the leds, and each is 33.3 ohm. And when I engage the first stage of the switch, the voltage supply is around 6v. So if the Vf of this 35k is around 3.4v(Got these leds from a fellow flashaholic friend, Aw), then the V drop by resistor will be around 2.6v; and the I for each led will be around 2.6v/33.3ohm=78ma each. Definitely overdriven if the spec is at 20ma nominal for most leds, but further research will need to be done for a long term effects. So far so good.
Also, depending the leds that you plan to put in, you might have to dremel the protroding latch at the botton of the led flat, so it could fit into the led holes on the A2 bezel.
Viola, it works! Do check the new leds that you plan to swap in before you solder them on, and double check again with supply 3 x 1.5v to the led ring.
Another view from the back of the led ring
Comparisons, all pictures used the same exposure and shutter speed settings:
Original SF A2 vs Attitude
Original SF A2 vs 26k modded Attitude
SF 35k leds A2 mod vs Attitude, it just completely blows it out of water...and the 35k seems to be quite narrow in terms of its beam characteristics.
SF 35k leds A2 mod vs ARC AAA rev4(with Nichia CS, Issac, thanks for the correction )
Yet another swap
As stated in the update at the beginning of this post, finally, I have decided to put in the MJ uncut leds. They are more capable of handling long term overdrive so as long it is under 100ma. Assuming its nominal Vf is around 3v(which IIRC, it does not have as high Vf as normal 5mms), then the drive level is about ~90ma. Here are some comparison pictures of the SF A2 with MJ leds:
Original PT attitude, a comparable output to the original A2
SF A2 with MJ led, this picture does not do a complete justice of the level of light it gives...but comparing it to 35k, it is quite flood-ish and the light generated is about the same(or just a little less, from my naked eyes). Still, a really good improvement over common 5mm leds(which PT attitude is comparable to the original SF A2)
SF A2 35k leds mod, notice the beam is tight and the darker area unlit by this tight beam.
SF A2 MJ uncut leds mod, note the flood beam also covers the unlit area not lit by the 35k. And I am a lot of comfortable with this mod, knowing this tool will perform well and I can count on it when needed to.
Thank you for reading, hope yod have enjoyed the pix!