I figure it makes the most sense to start a new thread on the titanium Sapphire 25 instead of updating the original Sapphire Thread. I will borrow some images and probably some comments from there though. From the outside, the Sapphire 25 looks exactly the same as the Sapphire. The difference is in the converter and converter assembly. First some revisited pics:
The original Sapphire uses a converter I purchased from Arc Flashlights driving a Nichia 3 mm DS LED. The Sapphire 25 uses a constant current driver designed and manufactured for me in Japan by the same folks who have provided me with the 3S converters I am using in other lights currently.
The construction of the Sapphire Head is the same as the original as illustrated below:
The new converter is set at 25 mA constant current to the LED and the input voltage range for it is ~1V up to ~5V. This means that this converter will drive the LED at the target 25 mA whether regardless of the type of AAA battery used and it would even function properly on 2xAAA or a Li-Ion cell. The trace on both sides of the board is gold plated including any contact surfaces to enhance the ground path. I solder a .5 mm thick sterling silver ring on the PCB for the anode contact. The converter assembly (light engine) is retained in the head by virtue of an interference fit and seal around the 3 mm LED. It can easily be pulled out of the head if the need arise.
I decided to make my own PORON foam battery cushions and because they are hand punched, they each have their own unique eccentricities and form. My objection to the ones provided by ARC was in the large OD which put the foam into the thread area as well as beyond the PCB and onto the lip of the head. The cushions I have made and use here are smaller in diameter than the PCB and even those that have an obvious off axis cant (Leaning Tower of Pizza) do not interfere with the threads and remain attached to the backside of the PCB if removed from the head. A crude pic:
You will also notice that the LED does not sport a large cap as is the case with the ARC converter.
I should state that I have no issues with the ARC converter and for all I know it may be a more efficient converter. It certainly has a lot of history and a long track record! My primary reasons for going with a new converter are the desire to have a source independent of another flashlight manufacturer, hopefully a converter less sensitive to contact resistance and a converter that is constant current across the voltage range of the various batteries, likely to be used.
I have been using a couple of these Sapphire's for a number of months now with pre-production converters and I am quite pleased with the performance of them.
For all intents and purposes, I consider this light to be a Sapphire but I feel I should make a distinction because of the new converter and since the new converter is set via a sense resistor to be at 25 mA I figure calling it a Sapphire 25 makes some sense.
I also realize that since it is a new converter I should address the run time question. I did a runtime test in my integrating sphere with one of these and I used a Duracell alkaline AAA battery for the test:
I left the test run overnight having started it at about 10 AM and the next day, 22 hours later, the LED was still lit but at about .2 lumens or so. The important consideration was that the converter did not shut off but allowed the LED to carry on as best it could. You can see with the sample tested, the IS measured 5 lumens out the front. I don't know how accurate the IS is in testing the Sapphire but I am confident that the results are well with the realm of the population of these lights.