[Technical discussions] Sofirn SP35 - SST40, 21700 size, buck driver

They’ll want to exhaust their current batch before they make the next batch

The ATR version is listed as pre-order status on the site, so it probably hasn’t been released yet.

The non-ATR version was low stock as of 18-Feb, and replaced with the aforementioned around 20-Feb, directing those who still desired it to AMZ US and DE, then changed again at some point to US only.

Personally, I had one on order at sofirnlight.com, that was still “awaiting shipping,” but after notice that AMZ US had received stock of the non-ATR version (their orders had been shipping from CN), I hedged my bets, cancelled that order, re-ordered from AMZ, and received it a day later. At that time, AMZ had limited stock as well, which added a sense of urgency, but it appears that has been replenished.

I wanted to ensure acquisition of the non-ATR version, and that was the best, and now, seemingly only remaining way to do so, albeit at a slightly higher cost with a smaller discount and sales tax added. Whatever remaining stock of the non-ATR version exists appears to be in AMZ’s possession.

I was also expecting to receive the 4000mAh cell, but pleasantly surprised that the kit contained the 5000mAh cell. It also has the revised reflector.

In informal usage, running on high mode does cause the head to heat up noticeably, but still tolerably to hold with bare hands, so I have no regrets.

Hi
We now have a new version of SP35 with ATR, which is different from the previous SP35. Are you interested in testing these two flashlights and compare the differences between the two. This test is free. Please contact me if you are interested.

I’m reviewing the new model with ATR, hopefully that’ll be sent this week from my contact.

Sofirn, if you installed an Osram CULPM1 in the SP35 it would make an excellent pocket thrower

...or maybe Luminus SFT-40 as a nice compromise between Boost HX and SST-40.

or that, yes. I see Convoy will be using it soon

Hi
We now have a new version of SP35 with ATR, which is different from the previous SP35. Are you interested in testing these two flashlights now and compare the differences between the two. We can send you one from an independent station and send it for free .

SFT-40 or HX both sound good here for throw. Wish there was a HiCRI SxT40.

I’m interested in trying out the SP35 with ATR.

So far, I have the first batch SP35 (with a more floody beam pattern), without ATR.
I also have the next batch SP35 (with a more focused beam pattern), also without ATR.
Would love to try out the new SP35, with the ATR…

I don’t have an SP35 yet, but would like to compare the ATR with a SP33 V3 which had extreme output oscillations. And a full review, of course.

I see it only comes in 6000-6500K. How’s it look? White or blueish?

Mine is white, and quite clearly closer to 6000K, compared to my 6500K SC31B, which has a blue cast.

I’d like to see an OP version of the current reflector to bolster the short range a bit. Intermediate is this light’s strong suit.

For a thrower, maybe they’ll repeat the past with

flooder : thrower :: SP32 : SP31 :: SP35 : SP35T

I think Luminus SFT-40 could be a great emitter for SP35T, especially if it was available in 5000K CCT. It is basically the SST-40 without dome. It probably gets you a bit more peak intensity compared to SST-40. As an alternative (more lumens, less intensity) they could incorporate Luminus SST-70 (6V) into that light but then it takes to use a boost- or buck/boostdriver, like their SD05 diving light.

Thanks

Does anybody know if there are any plans for Sofirn to make this light in 4000k or 5000k?

They could easily offer a 5000K version but I suppose SST40 5000K is very limited right now. They have probably used them up for SC31 Pro and SP36 Pro.

SST40 4000K does not exist. XHP50.2 3V (as alternative) is not available in anything warmer than 5000K and even these are prone to greenish tintshift.

I’m really liking this updated sp35 with ATR working,looking forward for the reviews,seems like a good balance for lumens/battery duration and with thermal control you can give it to uneducated userà.

Meanwhile, I have received my new Sofirn SP35 (with ATR) from AliExpress, purchased a couple of weeks ago. Today, I have run a detailed analysis regarding runtime and temperature. Below you find the results:

Conclusion

In general, Sofirn did a great job with their new model SP35 as you get a decent price/performance ratio for a small budget. The initial version without ATR (sold out) received a lot of good feedback in forums like BLF and TLF and revealed how good a buckdriver with constant current regulation can be. Many customers appreciate the option to manually step down their lights with regard to proper safety precautions.

Now, with their new ("revised") version with ATR I feel a bit displeased. On a positive side I can confirm that ATR works effectively, i.e. the flashlight remains within its thermal limits of about 55°C. Overheating will be prevented successfully. On a negative side I discovered a way too aggressive regulation which cannot provide a steady continuous output. Quite the contrary, the output always fluctuates between 28% and 63% of its initial ANSI output. This is such a big difference that you can even notice it with your bare eyes. For some of you this "sawtooth" profile will remind you of Sofirn's SP33 V3 which has also received some negative feedback for its mediocre thermal regulation.

Sofirn shows how it can be much better with their SF47T model. There you will get a much smoother regulated output with fluctuations of only 8%. I include the runtime chart of SF47T for comparison below. I hope that Sofirn will be able to do some tweaking on SP35's thermal regulation. Apart from that there is not much to not like about this flashlight. If they were to offer more neutralwhite/warmwhite tints as well as a logarithmic ramping curve, it could become one of the most recommended budget flashlights.

My SP35 with ATR should arrive in the next few days to a week. I was very hopeful after seeing your SF47T test… Sofirn finally stepped up their ATR game! But alas, it looks like that better version didn’t make it into the SP35. What a shame. :frowning: