SF U2 question

Well, I just received my U2 today and am quite happy

but.. when playing with it, I notice that, apart from the distance between about 0.5.-1 ft., the beam has a big fat donut hole at any other distance! :scowl:

I thought SF was supposed to be redesigning their reflectors? Is anyone else experiencing this with new U2 shipments, or is mine just a dud? Just wanna know whether it's worth the trouble to go back to SF, or if this is a 'feature' of the new reflectors =P

Edit: looking at the pamphlet, my light seems to be a "Revision A 11-1-2004", and output is stated as 2-100 lumens. Though I have no way of verifying this, it is pretty durn bright... its donut hole can blow a donut hole in both my SF A2s (one on half-used and one on new batts) and my Pila GL4 (which admittedly is on batteries that're about on their last legs at the moment, but still...!) at close range.

thanks in advance for any help =)

cheers =)

Will let you know once I get my U2 in my hands. Hope that some greek postman didn't take a liking to my package...:sweat:

would appreciate your feedback when you get your light Flashgreenie keeping my fingers crossed for ya =)

luckily or unluckily, I had a cheapo light stolen by my mailman just a bit before I placed these orders, so I've gone on a strict registered/signature-delivery only regime since! Costs a bit more but for these expensive lights, it's really not that much.... plus I get to get my lights faster too... that's what I tell myself! :shrug:

The donut is fixable.

nice =) thanks for the info GR =)

i'm already halfway in bed and my attempt just now resulted in nothing except greasing my hand with silicone lubricant =P so... it's gonna have to wait till tomorrow. but when tomorrow comes....! :devil:

Warning!
That will void your warrenty if you take it apart.

If you can bare to be without your U2 for a couple weeks,
Surefire will fix/replace it for you.
Just call them up.

My U2 is great,
But I had to send in my L5,
its much better now.

No matter what, it will have alittle bit of a "hole".
Not really a hole, just dimmer in the middle.

~John

How low is the U2's low?

Is there a comparable flashlight, like maybe a SureFire L4 with McGizmo tailswitch?

Scott

beezaur said:

How low is the U2's low?

Click to expand...

I can only compare it to the SF L2 because that's the only other LED I've owned. The U2's low is defintely lower than the L2's (which was quite bright, actually). Subjectively speaking, I would say you need to get to about level 3 or so on the U2 to equal the L2's low. So the U2's low is about 2 levels lower than that. But it still seems a bit bright for some applications (e.g., stumbling around the room in the dark without waking your wife, etc.). Just my inexperienced observations...ymmv.

beezaur said:

How low is the U2's low?

Is there a comparable flashlight, like maybe a SureFire L4 with McGizmo tailswitch?

Scott

Click to expand...

the u2's low is still a bit brighter than a 22 ohm pcb in a L4 McE2S. I have both and wished the u2 would go a bit dimmer. A 15 ohm may be closer. I currently use the McE2S/60 ohm pcb in my l4 and really like the setting for late night walking in the inside of my house and works well for reading.

The donut on my early U2 isnt really a void. It apears so until you look close on a colored wall (mine are tan). What you would notice is that the void is whiter than the outside but appears as a void on a light wall due to the outsides tint. IF it were a true void my throw wouldnt be as good as my Gladius, but it is and lights up about 3-4times the area of the Gladius at 30yrds or so. If you have a supposed void, you might need to look at it on a nonwhite wall.

On my U2 Id say the donut effect is the result of the phosphor distribution density(and the artifacts of the cross caused by the 3 dies on the emitter), not a poor focus

well, the donut hole in mine isn't a void, but it isn't a differene in tint either... it's more a slight dimming in the middle. i just sent off a quick e-mail to SF asking about it, and if they say it's ok, then i'm ok =) it's plenty bright as is, and throw seems to be pretty good.... on that note, this weekend looks to be another beamshot taking weekend :huh:

Somy Nex said: "...the beam has a big fat donut hole at any other distance!..."

My 1st U2 #A07416 had a VERY pronounced doughnut pattern. It looked like a smoke ring at any brightness at any distance > 1 meter. It also had a flickering problem.

I returned it to Surefire and received replacement #A08480. It has a less obvious doughnut pattern. Still visible but not as pronounced. More obvious on low output than high. No flickering.

Output is superb -- well over 100 lumens based on lux meter reflection tests and comparing to my HDS EDC U60 which is calibrated to 60 lumens.

Tint is pure white. Based on the tremendous output and perfect tint, I'll live with a modest doughnut beam pattern.

Surefire's description says "perfect beam...no dark spots", so they'll replace anything you don't like. However it can take several weeks.

It seems very frequent and almost the norm for U2s to have a doughnut beam pattern. The question is to what degree and does it bother you. Considering the essentially ring-shaped Lux V emitter design it seems logical an in-focus beam pattern would be doughnut shaped.

Ivanhoe said:

the u2's low is still a bit brighter than a 22 ohm pcb in a L4 McE2S. I have both and wished the u2 would go a bit dimmer. A 15 ohm may be closer. I currently use the McE2S/60 ohm pcb in my l4 and really like the setting for late night walking in the inside of my house and works well for reading.

Click to expand...

That's odd my L5 with 22 ohm Mc2ES switch equals the U2's output on level 3.:thinking:

RJM

Well a small update...

I'm taking Jtice's advice and not unscrewing the bezel until I hear from SF. On the 222nd review, the beam really isn't that bad and I believe can live with it =)

Joema, fwiw, the serial on my U2 is A05367... it would seem to be from an earlier batch? but I really don't know how the serial numbers are done, so I won't try to guess. again will wait for SF's response =) the main reason is that shipping anything back to the US and waiting for it to come back here is prohibitive in terms of time and costs, so it'll have to be something that really annoys me before I work the warranty. sad fact of life, but that's how it goes =( but... is all good. i got my U2 and i'm gonna enjoy it for now

woohoo, got my U2 mine is #04925. Only manage to do a quick check in the office, didn't notice any doughnut. The only thing I notice is that in the middle of the beam has a slightly darker area than the outer area. Also notice quite a few scratches around the clip area. Is this normal???
Also a slight color mismatch between the bezel and the head. Bezel has a purplelish tinge.

My friend just got his U2 the other day from SureFire, and, well, it has a very small doughnut hole in its beam, too. Other than that, the beam on his is very white and SUPER bright! We did a white wall shootout in my garage the other day and it totally killed my PR-T in overall brightness and in beam tint. The tint on his made mine look ultra baby blue, with the U2 being a near perfect white with what looked like no tint whatsoever.... perhaps he won the Luxeon Lottery, who knows? *shrug*

I told him if he ever decides to sell it, to let me have first dibs at buying that little white light-emitting blowtorch! I hate to say it, but I'm jealous... :green:

Flashgreenie, good to hear your got your U2 :thumbsup: My donut hole isn't exactly a void in the middle but a dimmer area in the middle, surrounded by a ring. but i figure it really isn't that bad, and won't be a problem in practical use (might see it sometimes, but seriously... it won't be a problem), so i'm gonna live with it. i had 3 nicks that went through to the bare al on my bezel, all on the middle part. i don't like that they have those nicks, but i plan to throw this light around anyway so they'll probably eventually get those nicks. if i were to buy them to collect or keep (as a shelf queen, which i soemtimes do) then i'd be more concerned, but not with this particular unit

The tint on mine is pretty white, although quite a warm white. alone it's definitely white, but if i compare it to my peak or fenix, then it looks slightly yellower. but not a problem there. it's definitely a bright light, and still some great offers on it Schuey

overall quite happy with the U2, and i can probably live with the minor shortcomings for now.

Finally manage to get home in one piece with all this rain here in Athens.:sweat: Some comments on the U2. Comparing it with the HDS U60 I have at the moment, the U2 beams is white with a hint of yellow(guess that would make it warm). THe U60 had a blueish tint to its beam. The U2 beam is also much tighter compare to the U60. U60 has a lot more side spill. The lowest setting on the U2 is definately too bright for me for reading. THe U60 lowest setting is much better.
I can also confirm the slightly darker solid disc in the middle of the beam. No really noticeable doughnut. I don't really notice the slightly darker disc unless I am pointing at a completely blank wall.
Overall quite happy with the U2:thumbsup:
Only thing now is that I love the clicky tailcap of the U2 and now must upgrade my M3T with a clicky tailcap too...:sweat::mecry::sweat:

you guys seen this thread???
http://candlepowerforums.com/vb/showthread.php?t=99132&goto=newpost

yea, saw it =) made a small reply there =) no insert in mine, though it is of the newer design...:thinking: :shrug: