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

How much differences in throw would this have over sc31pro?

Probably very little, the reflectors can’t be very different in dimensions, the emitter is the exact same and is driven to basically the same level (maybe a bit less even).

Is this the same light?


The one and the same!

It looks like they’ll also be stocking it at Amazon eventually (non-aff link). I bought mine through Amazon; it shipped from China and arrived relatively quickly. Good pricing on the one directly from Sofirn’s website. When I buy stuff there, it usually arrives within a couple weeks - pretty fast for China shipping.

Dumb question, I am trying to learn all the terminology, what is the advantage of the buck driver (vs. which driver?)

More controlled/consistent output and, if implemented correctly, more efficient than some other styles. There’s an explanation thread here

Thanks, I will read more about it.

Does your SP35 beam look more like the one on the left or the right?

Left side beamshot is an “early batch” SP35, probably belonging to the 1st 100pcs.
Right side beamshot is a bit newer SP35.
(both shots taken at same camera setting: 1/10th second shutter speed, daylight white balance, ISO-800)

I’m guessing that, as a dealer early in the queue, and provided with a preview unit, Funtastic received one with the original reflector with the larger but inconsistent spill (“left”).

The beamshots in gchart’s review resemble the one of the right with the newer reflector, with a more clearly defined hot spot, less spill, and better uniformity.

It would be nice if Sofirn were to provide some official clarity on which version one would ship if ordering now. The sales figures on their stores (~150+ sold) would suggest that the early batch has been exhausted, but that would only apply if they don’t commingle the two versions in stock, with each shipment a random draw, and a lottery for the customer.

Something that hasn’t been mentioned here, but on TLF, are plans for a 35T, with a tail switch.

Based on the sp35?

No idea if they mixed them, good question.

Here they mention the SP35T so knew something was on its way

Yeah, definitely was the one on the left. Quite a shame as it makes the beamshots in my video review useless now.

Yes, mine looks like left too.

A little bummer really, if anybody knows if we can get replacement reflectors that would be neat :smiley:

What’s wrong with the one on the left? Just looks floodier to me.

With the old reflector the transition from spot to spill is not that smooth and looks rather unpleasant. Also you get a very noticeable green ring around the spot, which you can notice in the comparison shots above.

Here is mine at closer range:

At low to mid brightness the “corona/ring” surrounding the hotspot does look a bit greenish too on my early SP35 unit.

I suppose Sofirn can send updated reflector when requested.

I asked for a new reflector for SP31v2.0, since the ones I got had a ‘humid’ reflector (and reflectors can’t be wiped). Sofirn sent a new SP31v2.0 reflector after I requested (had to remind a few times)…

SP31v2.0 with “humid” reflector vs one that has been replaced with a newly sent reflector

Sofirn has the pocket SP35 pocket clip for sale standalone… Mentions it’s compatible with the SP35T as well. So it’s likely real and soon to be here. I just hope the tailcap can be purchased separately and work on the original. It’d be nice to have the option.

I think the driver would have to be modified to not use “soft power,” and illuminate/be “on” any time there is current available.

For example, the SP31 and SP32 are very similar, with the major difference the tail switch on the former.

But with the latter, while it will retain mode memory, the light will stay off after the circuit is broken by unscrewing the tail cap, then tightening it again. To turn it on again requires using the electronic switch.

Maybe they’ll also make other slight modifications with the T, like they did with those two.

I have installed SST40 5000K from Convoy and beam lopks much better. Hotspot and corona is now one color instead of bliish center and yellowish corona. Now i’m thinking to install Osram CULPM1.TG...

SP35 without stepdown version is availble on amazon.com now!

Grap a 10% off coupon to save money!


Does anyone have runtime graph for version with temp regulation?