# Cree XR-E in KL6 host



## CM (Oct 14, 2006)

I don't have much time to talk about this right now but I thought this might be of interest (KL6 courtesy of : )> though he doesn't know it at the time of this posting. Thanks Bill  ) :







This is a Cree XR-E in a KL6 host. Based on Cree's spec, the LED should put out about 140 lumens at 700mA. I can't get a good beamshot since this is a temporary mount and I need four hands to do the beam shot. The deep reflector does a decent job of managing the Cree's beam profile. The only drawback is that the hot spot is pretty small but the spill is quite wide. I can't get over how bright the Cree is, it just blows away U bin Lux III's at 700mA and the S bin Lux I's at 350-500mA. I won't even mention the K2's--they're not in the same league at all (unless you live up north and want some light with your heat :nana: )

Here's a comparison shot against a UWOJ lux III behind a IMS 27mm reflector 


Cree on the left, U bin behind a IMS27 reflector on right. Both LED's biased at 700mA. Lux reading of 6840 lux vs 9400 lux (don't get too caught up in the lux comparison since the KL6 has a different and bigger reflector)






Using a ceiling bounce test (a better measure of total output), the P2 bin Cree measures about 13% brighter. This is consistent with the Cree bin that I have which is mediocre. P4's should be a bit brighter and I expect some P4's in a week or so.

This is the measurement that confirms what my eye sees when switching back and forth between the U bin Lux III and the Cree.


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## Amonra (Oct 14, 2006)

did you recieve the XR-E from cutter ? does that mean that they started shipping ?


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## IsaacHayes (Oct 14, 2006)

Yeah where did you get it from?
Is it as much light as the LuxV?
Is the small hotspot bright with a lot of light, or the majority of the light unfocused?
We need a beamshot!!!


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## fnmag (Oct 14, 2006)

Patiently waiting to hear about availability of the Cree XR-E. Your results so far are impressive. Thanks.


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## evan9162 (Oct 14, 2006)

Are they using a conformal phosphor coating now rather than the coated lens? The picture you posted makes it appear that way.


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## IsaacHayes (Oct 14, 2006)

evan, yeah. And they still have the "global phosphur" (coated lens) which provides a little less color uniformity, but more efficiency. I'm not sure if you can order both P/N's yet.


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## monkeyboy (Oct 14, 2006)

Does the original KL6 converter board work with the cree? Have you measured the current to make sure it's not being overdriven?


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## Nitroz (Oct 14, 2006)

IsaacHayes,

I bought some of the XR Xlamp LEDs that had the coated lens. They put out a nice flood of light with a funky colored corona but overall were not that impressive. I would really like to try some of these new XE's with the clear dome.

Cm,

I know where I can buy them locally but would like to here some more results on these when you get a chance before I buy. I would like to test these against the k2 LEDs I have.


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## bombelman (Oct 14, 2006)

Interesting.....


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## havand (Oct 14, 2006)

Nice! I've got a couple on the way..Anyone have any reflector suggestions? I've herad MR-19 mentioned a few times.

CM: Did you mount it on a star or the bare emitter? If it was the bare emitter, how did you mount it?


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## Amonra (Oct 14, 2006)

BTW which lumen specific bin did you get ?


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## CM (Oct 14, 2006)

Amonra said:


> did you recieve the XR-E from cutter ? does that mean that they started shipping ?



No, these are not from Cutter. They're my own source who can only supply me a very limited number of samples. For everyone else, Cutter is your best bet.




IsaacHayes said:


> Is it as much light as the LuxV?
> Is the small hotspot bright with a lot of light, or the majority of the light unfocused?
> We need a beamshot!!!



From my eyes, it's not as much light as a W bin Lux V by any means. Bear in mind though that the sample I have is a P2. I expect P4's in a week or so. Also this is running at about half the power of a WXOT that I'm comparing with. For a low grade bin like I have, it's still impressive. It blows away my S bin Lux I's and my brightest U bin Lux III at 700mA. No question about it.

Beamshot? I'm working on it. I need four hands. Remember, the LED is just held in place behind the reflector. The KL6 is not mine so until I can get my own KL6 to play with....Someone needs to sell me a beat up KL6.




evan9162 said:


> Are they using a conformal phosphor coating now rather than the coated lens? The picture you posted makes it appear that way.


The samples I have use conformal coating. 



monkeyboy said:


> Does the original KL6 converter board work with the cree? Have you measured the current to make sure it's not being overdriven?



The Cree's are designed for 700mA though I wouldn't be reluctant to drive them much beyond that. The Cree's thermal characteristics are much better than Lumileds. And I've been overdriving those for years. The KL6 converter is a constant current buck so yes, no problem with the Crees.





havand said:


> ...CM: Did you mount it on a star or the bare emitter? If it was the bare emitter, how did you mount it?



Mine are mounted on stars. 

If you're going to DIY the mounting, you need reflow capability. I heard of someone using a toaster


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## evan9162 (Oct 14, 2006)

The Cree XL3-7090s that I've had didn't respond too well to overdriving. First, they had an exceptionally high Vf (4.5V at 700mA). Driving them at 1A resulted in a Vf of 5V, which started to slowly rise. The I/V curves from the XL3s I have are not at all like luxeons. With Luxeons, past 700mA, you only get small rises in Vf for larger changes in current - the I/V curve looks logarithmic. However, on the Crees, it looked linear. I don't know if the XR-Es would behave the same - it would be nice to see some I/V curves from these.


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## CM (Oct 15, 2006)

evan9162 said:


> The Cree XL3-7090s that I've had didn't respond too well to overdriving. First, they had an exceptionally high Vf (4.5V at 700mA). Driving them at 1A resulted in a Vf of 5V, which started to slowly rise. The I/V curves from the XL3s I have are not at all like luxeons. With Luxeons, past 700mA, you only get small rises in Vf for larger changes in current - the I/V curve looks logarithmic. However, on the Crees, it looked linear. I don't know if the XR-Es would behave the same - it would be nice to see some I/V curves from these.



I think you'll like these better:

Vf(V) ILed(A)
=========
2.7	0.01
2.75	0.02
2.8	0.04
2.85	0.05
2.9	0.07
2.95	0.09
3	0.11
3.05	0.14
3.1	0.16
3.15	0.2
3.2	0.22
3.25	0.24
3.3	0.27
3.35	0.29
3.4	0.33
3.45	0.39
3.5	0.45
3.55	0.52
3.6	0.59
3.65	0.64
3.7	0.7
3.75	0.8
3.8	0.88
3.85	0.95
3.9	1.03

Note, the only heatsink was the star so I ran this test *very* quickly. If you plot it, it will not look smooth but it is monotonic


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## CM (Oct 15, 2006)

Bump to add beam shots. Sorry, this is a white wall comparison only.


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## havand (Oct 15, 2006)

WOW, Look at the brightness of the sidespill. I recognize that the hotspot is 'smaller', but it also looks a fair bit more intense. Pretty impressive! Thanks for the shots!


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## 270winchester (Oct 15, 2006)

nice CM. 

BTW do you happen to have a shot of the Cree behind a KL1 or KL3 optic? Fro mwhat I have heard from the other Cree thread you mentioned that the beam profile of the Cree works decently with the TIR optic? I have been a fan of the KL1 optic for years now(you know what I'm talking about) and am very curious of what a KL1/P4 hybrid would do. For something in the 3-watt range I really consider many small reflectors to waste too much light to spill.


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## CM (Oct 15, 2006)

270winchester said:


> nice CM.
> 
> BTW do you happen to have a shot of the Cree behind a KL1 or KL3 optic? Fro mwhat I have heard from the other Cree thread you mentioned that the beam profile of the Cree works decently with the TIR optic? I have been a fan of the KL1 optic for years now(you know what I'm talking about) and am very curious of what a KL1/P4 hybrid would do. For something in the 3-watt range I really consider many small reflectors to waste too much light to spill.



Ask and ye shall receive. Note I have a small mis alignment of the optic and the LED. There's also a little sunset peeking through at the bottom of the pic 





Picture is slightly saturated. I drove the Cree at 350mA to get this but it's still too bright 
The mounting of the LED in the KL1 head is somewhat problematic. There is a channel that is designed to accept the Luxeon so this shot was taken holding the optic in front of the LED. Eyeballing the distances, I think that the plane of the die is compatible with the TIR optic if you can get the LED in the KL1 head. Some Dremel work will need to be done but I think it's worth it since you are going to get something brighter than a U bin.


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## IsaacHayes (Oct 15, 2006)

wow intense beam in the kl6 reflector, despite the led wanting to throw most its light forward. Guess the deepness of the relfectors is enough to get a good bright beam. I like that beam alot btw, nice tight intense beam, and bright sidespill!!! I'd for sure mod a KL6 to that!


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## Kryosphinx (Oct 15, 2006)

CM, is the beamshot of the KL1 optic using the rounded lens? From my experience, the lens does some funky things and changes the beamshot.


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## CM (Oct 15, 2006)

Kryosphinx said:


> CM, is the beamshot of the KL1 optic using the rounded lens? From my experience, the lens does some funky things and changes the beamshot.



The beamshot is with just the reflector, no rounded lens.


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## Tachyon (Oct 16, 2006)

Hi CM,

Are these LED's available in warm tints? Similar to the V1 and V0 tints?

Thanks
Tachy


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## trivergata (Oct 16, 2006)

I wonder how one of these would perform in a A19 head..............

I'd love to have one to try - what is the website that you guys are getting them from?

Josh


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## jtice (Oct 16, 2006)

looks great,
I am holind out bulding one of my A3 heads for one of these new Crees.
Will a Wiz2, Nexgen, DownBoy driver run these?

~John


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## bombelman (Oct 16, 2006)

trivergata said:


> I wonder how one of these would perform in a A19 head..............
> I'd love to have one to try - what is the website that you guys are getting them from?
> Josh


This is what I found:
http://www.cutter.com.au/proddetail.php?prod=cut651
Anyone correct me if I'm wrong...


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## CroMAGnet (Oct 16, 2006)

I was fortunate enough to see one of these in action last weekend and it was exactly as described in this thread. I got to compare it too and it was really impressive at 750mA. Bright, white, tight hotspot, lots of lumens!

It was in a slightly modified A19 Aleph with the reflector shaved down a bit to get the correct focal point.

I have one concern as I heard they don't come in the same mounted stars and therefore might need some creative heatsink mods. Has anyone else heard this?


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## Julian Holtz (Oct 16, 2006)

At Cutter, one can order them mounted on stars similar to the Luxeons.

If I wanted to attach them to a heatsink without a star underneath, I'd reflow solder the contacts to some thin tiffany copper tape and then glue the whole thing on the heatsink. The leads could be soldered to the copper tape then.


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## CM (Oct 16, 2006)

Tachyon said:


> Hi CM,
> 
> Are these LED's available in warm tints? Similar to the V1 and V0 tints?
> 
> ...



Cree bins by tint also. WD or WJ will yield the warm tint. Here's the binning info:

http://www.cree.com/products/pdf/XLamp7090XR-E_B&L.pdf




jtice said:


> ...Will a Wiz2, Nexgen, DownBoy driver run these?
> 
> ~John



Yes, any converter designed to run a LED like the Luxeon will drive these. 




CroMAGnet said:


> I was fortunate enough to see one of these in action last weekend and it was exactly as described in this thread. I got to compare it too and it was really impressive at 750mA. Bright, white, tight hotspot, lots of lumens!
> 
> It was in a slightly modified A19 Aleph with the reflector shaved down a bit to get the correct focal point.
> 
> I have one concern as I heard they don't come in the same mounted stars and therefore might need some creative heatsink mods. Has anyone else heard this?



It kicks arse at 350mA, and at 750mA it's very nice also. I prefer lower power drive myself (around 500mA) since I want practical runtime. 

I'm gonna pick up an Aleph 19 and make myself one. As far as mounting, they do require a special PCB or you can get them installed on a star. They're designed for reflow soldering so it's not as easy to diy but there are a lot of creative folks here on CPF--that problem will be overcome.


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## jdriller (Oct 16, 2006)

Thanks for the info, CM.


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## Nitroz (Oct 16, 2006)

CM said:


> It kicks arse at 350mA, and at 750mA it's very nice also. I prefer lower power drive myself (around 500mA) since I want practical runtime.



How does the Xlamp at 350 compare to the Lux III at 700?

I can't wait to see what the supplier I am using will get from Cree. I am ready to upgrade my QIII and KC-1 with these.


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## IsaacHayes (Oct 16, 2006)

Reflow soldering, but why couldn't one just use AA epoxy?


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## AlexGT (Oct 16, 2006)

Can you post a beamshot using a IMS-27 or McR-27 reflector? Brighter than a U bin!!! and a tight hotspot with lots of spill? OMG!!! I want one!!!, I would love to buy a premium bin of these with a WO or XO tint. to put inside a LH, Name the price! 

Thanks!
AlexGT


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## CM (Oct 16, 2006)

Nitroz said:


> How does the Xlamp at 350 compare to the Lux III at 700?
> 
> I can't wait to see what the supplier I am using will get from Cree. I am ready to upgrade my QIII and KC-1 with these.



P2 bin Cree is rated 67.2lm to 73.9lm at 350mA.
A T bin Lux III at 700mA is 67.2lm to 87.4lm at 700mA

A P4 Cree will do 80.6lm to 87.4lm at 350mA. That's upper T bin Lux III territory at half the current. Since Vf appears to be similar to Lumiled's, it's the same output as a Lux III at half the power.

Note that the Cree's binning structure is much tighter than Lumileds. So for a given bin, instead of a 30% range in luminous flux, it will be less than 10% variation.



IsaacHayes said:


> Reflow soldering, but why couldn't one just use AA epoxy?



Good question actually. I don't see why not as long as you can make the connection to the LED.



AlexGT said:


> Can you post a beamshot using a IMS-27 or McR-27 reflector? Brighter than a U bin!!! and a tight hotspot with lots of spill? OMG!!! I want one!!!, I would love to buy a premium bin of these with a WO or XO tint. to put inside a LH, Name the price!
> 
> Thanks!
> AlexGT



Tried the IMS-27 and the beam was, well, not good. In fact, tried with 17 and 20mm ones as well. I think the reflectors may need to be modified but haven't got around to trying that yet. The best reflectors will be very deep like the KL6 or the McR-19 which was designed for the Crees.


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## Nitroz (Oct 16, 2006)

WooHoo! I'm siked and ready to make a little screamer. 

I with you on powering these at 500mA on some single cell lights. Now when it come to the multicell lights I will have togo full throttle.

Thanks for the pictures and info CM. :twothumbs


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## Julian Holtz (Oct 17, 2006)

Ok IsaacHayes, for some strange reason my computer hates you. All of my browsers crashed multiple times when I wanted to post this answer. I had to rewrite it 3 (!!!) times 
It only worked when I removed the quote of you that goes like this:

"Reflow soldering, but why couldn't one just use AA epoxy?"

My answer:


I guess because it is not electrically conductive?



When the LED is mounted on a heatsink which is bigger than its base, one will have a difficult time to access the contacts.

Therefore, I thought up this solution:










It is theoretically, but I cannot think of a reason why it should not work.
One needs some adhesive tiffany copper tape that one sticks on a small piece of aluminium sheet metal. From the middle of the tape one removes a piece that is as broad as the distance of the LED contacts. After putting some solder paste on the copper tape, one can stick the LED on it. Alternatively, one can apply a thin layer of solder on the tape and the LED contacts using normal soldering wire.

The sheet metal is now put on a flat-iron pre-heated on maximum tenperature. Hopefully, the solder will melt and connect the LED contacts to the copper tape. 

After the sheet metal is removed and has cooled down, one can remove the LED soldered to the copper tape from it.

One can put insulating tape under the copper tape and then glue the LED to the heatsink. The cables for the LED are soldered to the copper tape.


From my point of view, this is a good method to keep the gap between the LED base and the heatsink to be filled with epoxy as small as possible.

Cheers,

Julez


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## CM (Oct 17, 2006)

Julez,

There are contacts at the top of the LED that you can access for connections also. The base has through holes that connect the contacts between the top and bottom of the LED. As long as making the connection doesn't get in the way of optics, this should work.


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## Julian Holtz (Oct 17, 2006)

Ok, thanks for this info!

Damn...and I put so much efford in this description 

Ok, at least I can hope that it is useful for someone who wants to use optics *that get* in the way


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## KDOG3 (Oct 17, 2006)

Whoa! Can this be put in a U2? I would love to see my U2 with one!


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## KDOG3 (Oct 17, 2006)

I'd also like to stick one of these in my L1..... one P4 please!


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## chimo (Oct 17, 2006)

On the older Cree emitters I have also ground off the bottom contacts with a dremmel when I was mounting them to a heatsink. I used Arctic Silver to attach it. Then I did not have to worry about them shorting. I used the top electrical contacts.

Paul


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## Gnufsh (Oct 17, 2006)

CM said:


> Julez,
> 
> There are contacts at the top of the LED that you can access for connections also. The base has through holes that connect the contacts between the top and bottom of the LED. As long as making the connection doesn't get in the way of optics, this should work.


Can you solder normally to the top connections? WHat's the best way to do this without frying the LED?


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## Kryosphinx (Oct 17, 2006)

If you're really concerned about it shorting, you can put the XR-E on a pedestal that is only large enough for the heatsinking part.


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## CM (Oct 17, 2006)

chimo said:


> On the older Cree emitters I have also ground off the bottom contacts with a dremmel when I was mounting them to a heatsink. I used Arctic Silver to attach it. Then I did not have to worry about them shorting. I used the top electrical contacts.
> 
> Paul



Thanks Paul. This is good to know. I have a dremmel and look for every excuse to use it


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## IsaacHayes (Oct 17, 2006)

Julian, yup should work the only thing I see is solder probably conducts heat better than aa epoxy, but you can't solder to aluminum anyways, you'd need a copper heatsink. BTW I used firefox browser and quotes never crash on me..


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## SuperTorch (Oct 18, 2006)

When is the clear dome one do out? Would they survive at 800ma-1000ma?


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## Julian Holtz (Oct 18, 2006)

Hi Isaac,

you are certainly right about the heat conductivity issue.
Actually, it is possiple to solder aluminium even with normal soldering wire, but it is fairly complicated. One has to cover the surface with oil, then grind it shiny to get rid of the oxide layer. The oil has to stay on to prevent any oxygen from acessing the surface. When you are done, one heats the aluminium from underneath with a flame or something, an with a really big soldering iron (~100W) one applys the solder from the top. This procedure is a little messy and I only tried it once as a proof-of-concept, but if this would be the last resort, it is worth a try.

I tried the normal internet explorer, Crazy Browser and Maxthon Browser, but it was rather difficult. Just doing a quote would work, doing a long text works too, but both combined --->crash.

Cheers,

Julez


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## NewBie (Oct 18, 2006)

This method works also:


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## havand (Oct 18, 2006)

You just soldered the wires to the sides and sit the edges on two pieces of tape?


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## CaLux (Oct 18, 2006)

if it's possible that I can order special bin code for low Vf like Luxeon J-Bin, forwarding voltage betweem 3.27-3.51V ?


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## havand (Oct 18, 2006)

Look at the bin sheet...The VF is decently low at 350ma and climbs as the current goes up. I don't have the datasheet infront of me though.


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## Julian Holtz (Oct 18, 2006)

havand said:


> You just soldered the wires to the sides and sit the edges on two pieces of tape?


 
I guess it was the other way round. With the cables putting mechanical force to the diode it would be difficult to perform a reflow- solder like process.

I think NewBie first put the tape on the copper (looks like the Kapton Tape I use for R/C plane pattery packs which can handle 400°C) an then soldered the led to it.
Soldering the cables on now would be easier than doing it in the first place.

Please correct me, NewBie, if I am writing nonsense


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## monkeyboy (Oct 18, 2006)

I thought luxeon IIIs were binned at 1000mA? Surely it's not a fair comparison in that case.


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## havand (Oct 18, 2006)

No. 750ma, i believe.

EDIT: Wait, you said BINNED at, not rated for. I don't know anything about the conditions under which they're binned.


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## monkeyboy (Oct 18, 2006)

I'm confused now. I can't find this information on any of the Luxeon datasheets.


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## havand (Oct 18, 2006)

Their rated lumens is at a drive current of 750ma...is that what you mean?


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## monkeyboy (Oct 18, 2006)

yes, that's what I mean by binned.


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## NewBie (Oct 18, 2006)

Julian Holtz said:


> I guess it was the other way round. With the cables putting mechanical force to the diode it would be difficult to perform a reflow- solder like process.
> 
> I think NewBie first put the tape on the copper (looks like the Kapton Tape I use for R/C plane pattery packs which can handle 400°C) an then soldered the led to it.
> Soldering the cables on now would be easier than doing it in the first place.
> ...




First I polish the copper until it gleams.

Then I put the Kapton (Polymide 33 I believe) on it, at a spacing that matches the thermal pad solder area.

Then I tin the copper up.

While things are still hot, I put the LED on, then heat on each side. 

Once things flow, remove the heat source immediately. I then forcefully cool the copper slab down.

If you are going to be *soldering* on your CREE LEDs, make sure that you have "dehumidified" (baked) them first, or they were stored with desiccant and the indicator still indicates things are dry. Failure to do so, will result in weird things to the gel and phosphor inside, and a dramatic loss in light output. It can also result in color shift in the output. This is not a problem if you are not soldering on them.

Might I suggest one orders some of the XR or normal XL LEDs to practice on first, if you are not skilled at soldering. I think the reds are the lowest cost.

Thats an old picture I took in 2005 to show the technique I used in 2004 for their LEDs.


Luxeon III is binned at 700mA.


.


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## CM (Oct 18, 2006)

NewBie said:


> First I polish the copper until it gleams.
> 
> Then I put the Kapton (Polymide 33 I believe) on it, at a spacing that matches the thermal pad solder area.
> 
> ...




Lotsa good info there (especially dehumidifying). Thanks for posting.


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## Kryosphinx (Oct 19, 2006)

How exactly do you bake them?


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## Mags (Oct 19, 2006)

Imagine a tri lux build with these things...


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## marxs (Oct 20, 2006)

if the McR-19 fits these leds how does the McR-20 do? id love to put this in a pd! im guessing around 100lumens out the windew at 580ma?


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## 270winchester (Oct 20, 2006)

Mags said:


> Imagine a tri lux build with these things...



screw that, imagine the Elektrolumen XR-E ELX-12(12 of them)...


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## photorob (Oct 20, 2006)

It wouldn't fit in a pd. The pd has only enough room to fit a round LED. This thing was square the last time I checked.


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## NewBie (Oct 21, 2006)

"If the LEDs have been exposed to greater than 45% relative humidity for more than 168 hours after opening the vacuum-sealed package, the exposed reels must be baked at 80°C for 24 hours. The reels should be removed from the plastic bag before baking. Exposure to temperatures higher than 80°C could result in damage to the tape and/or reel."

There are other good things to note in their soldering and handling guide:
http://www.cree.com/products/pdf/XLampSolderingandHandling.pdf


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## vacuum3d (Oct 21, 2006)

NewBie said:


> "If the LEDs have been exposed to greater than 45% relative humidity for more than 168 hours after opening the vacuum-sealed package, the exposed reels must be baked at 80°C for 24 hours. The reels should be removed from the plastic bag before baking. Exposure to temperatures higher than 80°C could result in damage to the tape and/or reel."
> 
> There are other good things to note in their soldering and handling guide:
> http://www.cree.com/products/pdf/XLampSolderingandHandling.pdf




NewBie, can you put this in a phrase that uneducated people can understand? Are they saying that if the leds get wet, we have to bake them to evaporate the moisture out of them? Obviously, most of the folks here are going get some loose leds probably cut from a reel. If we keep them in room temperature, do we have to worry about what they're talking about?

Thx,
ernest


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## NewBie (Oct 21, 2006)

vacuum3d said:


> NewBie, can you put this in a phrase that uneducated people can understand? Are they saying that if the leds get wet, we have to bake them to evaporate the moisture out of them? Obviously, most of the folks here are going get some loose leds probably cut from a reel. If we keep them in room temperature, do we have to worry about what they're talking about?
> 
> Thx,
> ernest




In many areas, yes, most definitely. Moisture is water in the air you breathe, known as humidity.

Remember, this is only if you are soldering them. It does not apply with use. The same type of thing also applies to Nichia, OSRAM, and the Royal Philips LumiLEDs Luxeon K2, and if you are going to solder the slug of the Royal Philips LumiLEDs Luxeon III or V, it is prolly a wise thing to do. It is extremely important if you plan on reflow soldering them, like on a hot plate, IR, or convected heat, or whatever. Also, if they are not in dry vaccum sealed packages with dessicant, you have no idea what they have been thru, so it is probably a good idea.

The heat speeds up the elimination of moisture, but if you don't plan on using them for awhile, toss a big bag of dessicant in a sealed bucket that doesn't pass moisture (most plastics pass moisture, glass with metal lid, or metal containers work well), and store them in there. When you get around to utilizing them in a month or two, they will be dry. If you have an old humidity indicator card, that helps, as you can look at it when you open it, to see what the humidity level inside was.


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## CM (Oct 21, 2006)

I'm glad I live in the desert. My environment IS my dessicant


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## NewBie (Oct 22, 2006)

So thats why everyone from Arizona always looks like a raisin or prune!


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## marcdilnutt (Oct 22, 2006)

I am thinking of one of these in an Orb Raw. Do you think it would work?
marc


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## CM (Oct 24, 2006)

NewBie said:


> So thats why everyone from Arizona always looks like a raisin or prune!



Well at least we're not suicidal.


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## chanamasala (Oct 24, 2006)

Are there any epoxies that are conductive that a not-reflow-soldering-adept human can use instead?


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## marcdilnutt (Oct 25, 2006)

chanamasala said:


> Are there any epoxies that are conductive that a not-reflow-soldering-adept human can use instead?


There are epoxies available that are both electrically conductive or thermally conductive but i dont know if either is suitable for this application.
Marc


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## McGizmo (Oct 25, 2006)

Hi guys,
I think I can make an on topic contribution here.












In both images, a stock L6 is on the left and a modified L6XR is on the right. In the mod, I inverted the original heat sink and slightly counter bored it to accept the XR-E mounted on MCPCB. I also removed about .100" from the rear of the reflector in the head. This puts the rear face of the reflector about even with the top surface of the metal dome retainer of the XR-E LED. I also replaced the stock converter with a DB917 driver. CM states that the stock driver should work and I dever to his expertise. I invaribly kill the stock converters when I power them from the bench supply.  It sems if you short the input leads while under power the magic smoke is let out. Interesting to note in the beam shot above, both LED's are being driven at ~ 900 mA but one is requiring around 7V and the other about 3.5V. The beam on the right takes about half the power to produce as the one on the left. 

I have a bunch of other test lights and reflectors in the works and hope to do somemore comprehensive beam shots and photos later on.

I agree with CM that the L6 is a good selection as host for the XR-E. :thumbsup:

Some time ago I came to the conclusion that the stock L6 was closest in beam pattern and distribution to a XR-E behind a McR19 and in fact, driving the XR-E at 525 mA, the beams are very similar!


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## CM (Oct 26, 2006)

Yowsa Don, thanks for getting us back on track. 

What do you think about shaving the bottom of the MCPCB? The KL6 heat sink is pretty thin as it is. Also I'm wondering if we all have the same MCPCB. Mine is 2 mm in thickness. Thinning it down and aportioning part of the remaining thickness to the host may be a good compromise.


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## stoven (Oct 26, 2006)

Does anyone know the z axis location of the point source for the XR-E? Knowing this would help a lot with getting a reflector to work.


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## monkeyboy (Oct 26, 2006)

CM, 

Did you have to grind down the reflector of the L6 for your beamshot? Seems a bit strange how both yours and McGizmos focus correctly with different z-axis locations.


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## McGizmo (Oct 26, 2006)

CM,
I only had to counterbore the back side of the heat sink to a depth of about .020" as I recall (could have been asmuch as .040") but this served as a centering feature as well. THere is still much more mass "inboard" and the path of thermal relief to the head, via the flange of the sink where it mates to the head is unchanged. There is a net gain of thermal mass in the sink and we are tasking the sink with transporting possibly less than half of the heat compared to the stock configuration? I used thermal grease and two threaded fasteners to bolt the MCPCB to the sink plate. My MCPCB is 2 mm thick and it is a part that Wayne and I came up with and are using for various applications. THe plane of thermal transfer from MCPCB to sink plate is still above the plane of transfer to the head but closer to it by keeping the MCPCB at full thickness. :shrug:

I took about .100" from the rear of the reflector but this was more than necessary for actual clearance requirements.


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## CM (Oct 26, 2006)

monkeyboy said:


> CM,
> 
> Did you have to grind down the reflector of the L6 for your beamshot? Seems a bit strange how both yours and McGizmos focus correctly with different z-axis locations.



The LED was held in place by hand (the KL6 was not mine) 



McGizmo said:


> CM,
> I only had to counterbore the back side of the heat sink to a depth of about .020" as I recall (could have been asmuch as .040") but this served as a centering feature as well. THere is still much more mass "inboard" and the path of thermal relief to the head, via the flange of the sink where it mates to the head is unchanged. There is a net gain of thermal mass in the sink and we are tasking the sink with transporting possibly less than half of the heat compared to the stock configuration? I used thermal grease and two threaded fasteners to bolt the MCPCB to the sink plate. My MCPCB is 2 mm thick and it is a part that Wayne and I came up with and are using for various applications. THe plane of thermal transfer from MCPCB to sink plate is still above the plane of transfer to the head but closer to it by keeping the MCPCB at full thickness. :shrug:
> 
> I took about .100" from the rear of the reflector but this was more than necessary for actual clearance requirements.



So you guys are using a custom MCPCB? Mine is what came with the part--interesting they're both 2mm thickness. I like that you are using an MCPCB in your applications since they are better suited to modders. I tried working with these as emitters and turned out to be disasters (destroyed two very nice UV 7090's and a nice XR-E). I can't wait to see what you come up with in larger form factors for the Cree though the Aleph is growing very quickly on me :naughty:


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## IsaacHayes (Oct 26, 2006)

Yeah, a HD45 sized reflector tuned for the cree would be an awesome thrower!

CM: could you please post more info or a beamshot of the cree in the mag reflector? I need to know if I should gather materials and build me a replacement for my U-bin mag.. as it's my thrower light...


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## monkeyboy (Oct 26, 2006)

CM said:


> destroyed two very nice UV 7090's and a nice XR-E


 
Oh dear. Were they destroyed by soldering?

Has anyone tried using electrically conductive epoxy instead of solder on LEDs? I have seen silver electrically conductive epoxy with a low resistivity of 0.001 ohm/cm. This is nowhere near as good as solder but surely the resistance of the bond would still be negligible?


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## Anglepoise (Oct 26, 2006)

How about this. On the flat heat sink part of the flashlight the Cree will mount to, you drill a couple of counter bored holes with small springs in the recess. 
The positive + voltage side would have to be in a Teflon slug pressed in and then drilled. The Cree is epoxied to the flat area as per a Lux 111 emitter and held in while it sets. The two little springs make the contact to the underside of the Cree and connect electrically to the driver No soldering at all. 
Obviously there would be experimenting and fooling around to get this to work
.....,might work.


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## IsaacHayes (Oct 26, 2006)

guys, it's easy, just solder wires to the top pads for electrical connection. Paint or file off the connections on the bottom if you're worried about shorts. Then use arctic alumina epoxy to set the led on the heatsink. The slug is neutral. The re-flow soldering is only for assembly line stuff, and that it's the best way to transfer heat (metal solder conducts better than thermal epoxy). Ideally, you'd solder them to a copper heatsink, and that'd have the ultimate heatsinking. Then the copper would go into an aluminum light.

Springs are a silly idea. No offense. But that's way too much work and un-reliable stuff there. It's easier than that. Let's not get too complex in our creativity!


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## Loomy (Oct 27, 2006)

I thought everyone would be getting XREs on the little PCB. According to the PDF it is electrically insulated on the bottom and has +/- contacts on the top. Soldering to those shouldn't be a big deal, it's nothing you can't learn to do with some practice on an old scrap PCB.


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## 270winchester (Oct 27, 2006)

McGizmo said:


> In both images, a stock L6 is on the left and a modified L6XR is on the right. In the mod, I inverted the original heat sink and slightly counter bored it to accept the XR-E mounted on MCPCB. I also removed about .100" from the rear of the reflector in the head. This puts the rear face of the reflector about even with the top surface of the metal dome retainer of the XR-E LED. I also replaced the stock converter with a DB917 driver. CM states that the stock driver should work and I dever to his expertise. I invaribly kill the stock converters when I power them from the bench supply.  It sems if you short the input leads while under power the magic smoke is let out. Interesting to note in the beam shot above, both LED's are being driven at ~ 900 mA but one is requiring around 7V and the other about 3.5V. The beam on the right takes about half the power to produce as the one on the left.
> 
> I have a bunch of other test lights and reflectors in the works and hope to do somemore comprehensive beam shots and photos later on.
> 
> ...



Nice pic Don. Looks like I'll be getting a second PD after all...


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## CM (Oct 27, 2006)

IsaacHayes said:


> guys, it's easy, just solder wires to the top pads for electrical connection. Paint or file off the connections on the bottom if you're worried about shorts. Then use arctic alumina epoxy to set the led on the heatsink. The slug is neutral. The re-flow soldering is only for assembly line stuff, and that it's the best way to transfer heat (metal solder conducts better than thermal epoxy). Ideally, you'd solder them to a copper heatsink, and that'd have the ultimate heatsinking. Then the copper would go into an aluminum light.
> 
> Springs are a silly idea. No offense. But that's way too much work and un-reliable stuff there. It's easier than that. Let's not get too complex in our creativity!



That's exactly how I did my Aleph build. The KL6 heatsink is anodized so I think the same idea will work. Just epoxy to the heatsink and solder wires to the top.


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## Pinter (Oct 27, 2006)

I used Arctic Silver Thermal Adhesive under the whole emitter (there was no Arctic Alumina at home). Attached on an anodized aluminium heatsink.

Description on http://www.arcticsilver.com/arctic_silver_thermal_adhesive.htm states that it has negligible electrical conductivity: "Arctic Silver Thermal Adhesive was formulated to conduct heat, not electricity. NOTE: Even though Arctic Silver Thermal Adhesive is specifically engineered for high electrical resistance, it should be keep away from electrical traces, pins, and leads. The cured adhesive is slightly capacitive and could potentially cause 
problems if it bridged two close-proximityelectrical paths."

I don't know if I will have problems regarding its capacitive property, but it works for me.


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## NewBie (Oct 27, 2006)

McGizmo said:


> Hi guys,
> I think I can make an on topic contribution here.
> 
> 
> ...


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## Christexan (Oct 27, 2006)

No need to worry about Arctic silver capacitance in this usage, it would only be enough to potentially damage very ESD sensitive devices (sensitive microchips, power controllers are protected already against such surges), and it only applies if very close traces are bridged, then build a charge which is discharged upon the circuit opening. We are talking milli/micro discharge levels here, well below any problem levels in our types of circuits (and the only typical "capacitance bridge" location in this case would be the interface from heatsink (typically neutral/not part of the circuit) to slug (again, neutral or not usually designed as part of the circuit path), so a non-issue. The only potential capacitance bridge that would be "in-circuit" would be from the + to - contacts on the Cree, and they are spaced so far apart, it would take a lot of power to create an electrostatic field over that spacing in a "slightly capacitive" substance. (Your LED and related circuits would be dead long before that issue arose).


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## Anglepoise (Oct 27, 2006)

So if we embed the XR-E in Arctic Silver, and solder on the upper edges, do we still have this 'moisture problem' that requires baking at 80° for 24 hours?
Or is that only if 're flow' equipment is used?


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## Gnufsh (Oct 27, 2006)

Anglepoise said:


> So if we embed the XR-E in Arctic Silver, and solder on the upper edges, do we still have this 'moisture problem' that requires baking at 80° for 24 hours?
> Or is that only if 're flow' equipment is used?



I'm wondering this as well.


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## CM (Oct 27, 2006)

NewBie said:


> Running half the power to get the same output, yowsers!...
> 
> BTW, for some reason, these CREE XR-E LEDs make me feel like a kid in a candy store!




The Cree has gotten me all excited about LED's again. Someone finally broke past the "incremental improvements" that Lumileds have been making over the last four years. The K2 was (is) a big disappointment and then Cree came out and said "that's not a LED, THIS IS A LED" :nana: 

Still looking for someone to sell me a KL6--cheap


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## Amonra (Oct 28, 2006)

A method i have used to stick cree leds is to use a short copper rod the diameter of the led slug and refolw solder or AA the led on top of it, you then drill a shallow hole the diameter of the rod in the heatsink and aa the rod with the led on top inside the hole and leave the led a millimeter above the heatsink, this insulates the bottom contacts from the heatsink and increases the surface area for heat transfer with the heatsink. you then solder the wires to the top of the led.


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## IsaacHayes (Oct 28, 2006)

Amonra: yeah I had that idea too, reflow it to a small copper tower, and then AA epoxy it to a larger aluminum HS. That way the heat is pulled fast to the copper since it's soldered, and there is more surface area for the less efficient thermal epoxy to spread the heat into the main aluminum HS.

I have some old elektrolumens flat 1/4" thick aluminum heatsinks. If I were to get some copper rod, I could easily make a pretty good heatsink for a mag.. Hmmmm!


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## McGizmo (Oct 28, 2006)

On topic, below is a beam shot with a stock L6 on top and a L6-XR-917 on bottom:


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## NewBie (Oct 29, 2006)

McGizmo!!!


That is Simply Amazing!


Oooh, my wallet aches...looks like you turned the CREE into a throw monster!



Very nicely done.


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## KDOG3 (Oct 29, 2006)

Holy crap. I just GOTTA get one of these!


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## McGizmo (Oct 29, 2006)

Hi guys,

The L6 mod is not a difficult mod as mods go and if in fact the existing driver will work with the XR-E LED, one could design and make a simple heat sink replacement where the modder would just swap out sink and LED. You will have to remove some of the rear of the reflector though to allow the XR-E ingress as well as isolation of its leads.

I personally can't get too excited about going after this mod because I have what I consider to be a easier solution in the McR-27XR reflector and an E-series (Aleph) head as well as some stand alone x2 converter solutions like the 27XR proto:






The L6XR above and 27XR below; both with DB917 converters. 

I would agree that there are some L6's out there that might benefit from a rework though!


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## digitaleos (Oct 29, 2006)

Chris


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## KDOG3 (Oct 29, 2006)

How much work would need to be done to get a Cree in the L1 head? I have one of the new LXK2-PW14-U00: bin UW0K K2 emitters from PhotonFanatic which should put out around 50-ish lumens from the L1 on high. Through the optic, that will be a stunner. I'm wonder what the Cree would do...


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## NewBie (Oct 29, 2006)

Son of a Gun McGizmo.

I'm having problems just keeping up with the new stuff you are showing, yet you keep posting more mods, each of which took you a lot longer to do, than it takes me to look at your excellent work.

I took and modified your photo a bit, so I could see the flood better, and noticed a HID looking shaft comming out of the front of the XR-E lights:






Are you certain you didn't get your pictures mixed up with another secret McGizmo skunkworks project?


.


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## McGizmo (Oct 29, 2006)

Newbie,
I first noticed that "shaft" in a beam shot of my Ti proto A19XR with GD700:







I think you guys are also going to see some illusions on white walls with thes XR-E's. Ihave mentioned it elsewhere but I think a particular ring of what looks like dark is an illusion and not an area of less intensity. I think these LED's have enough flux to overwhelm the eye even in reflected beam return at close distances.


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## NewBie (Oct 29, 2006)

I took your PD photo and A19 XR-E photos and made an animation out of them, enjoy!






(Who turned on the lights???)


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## Archangel (Oct 29, 2006)

McGizmo said:


> I think you guys are also going to see some illusions on white walls with thes XR-E's. Ihave mentioned it elsewhere but I think a particular ring of what looks like dark is an illusion and not an area of less intensity. I think these LED's have enough flux to overwhelm the eye even in reflected beam return at close distances.


XR-Es aren't the only ones that can do that. (smirk) It's nice to read that someone else has noticed the affect as well. I don't think it's an illusion, though.


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## IsaacHayes (Oct 29, 2006)

Jar, hey that's a great idea, that's really good at comparing them, it's like fliping lenses for an eye exam back and forth. "this, or this".. lol


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## NewBie (Oct 30, 2006)

Thanks Issac.


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## Kiessling (Oct 30, 2006)

Cool gif there, thanx! 
But the clouds do not match ... :nana:


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## BigHonu (Oct 30, 2006)

NewBie said:


> I took your PD photo and A19 XR-E photos and made an animation out of them, enjoy!
> 
> 
> 
> ...




nice!


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## NewBie (Oct 31, 2006)

I'm glad to see others are starting to use the techinque already.


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## wquiles (Oct 31, 2006)

NewBie said:


> I took your PD photo and A19 XR-E photos and made an animation out of them, enjoy!
> 
> 
> 
> ...


NewBie,

How do you actually create this type of animated image? I want to learn 

Will


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## matrixshaman (Oct 31, 2006)

Paint Shop Pro has an animation shop and I think most major Paint/Photo/Image manipulation programs probably do also.


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## NewBie (Oct 31, 2006)

wquiles said:


> NewBie,
> 
> How do you actually create this type of animated image? I want to learn
> 
> Will




There are a bazillion tools to do it:

http://www.google.com/search?num=100&hl=en&lr=&q=animated+.gif+tool


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## jch79 (Nov 1, 2006)

Photoshop coupled with ImageReady works really nice as well.


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## marxs (Nov 1, 2006)

man i cant wait for the cree PD! that cree just over-fluxes the current PD. btw, am i right to guess that the UYAJ PD was on high?


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## wquiles (Nov 1, 2006)

NewBie said:


> There are a bazillion tools to do it:
> 
> http://www.google.com/search?num=100&hl=en&lr=&q=animated+.gif+tool


Thank you NewBie and others - I am off to read/learn about this ... 

Will


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## UKSFighter (Nov 3, 2006)

Awesome mods and pics. This new technology has me really excited.


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## CM (Nov 5, 2006)

Well we strayed a bit off the beaten path here. I just completed a real KL6 mod with the Cree, I'm not just holding the LED behind the reflector like I was here. For the results click here:

KL6 Cree vs. U2


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## milkyspit (Nov 8, 2006)

CM, your PM inbox is full. Answer is YES. Could you clear out some space so I can send you the full response?

Everyone else: show's over! Move along.


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## CM (Nov 8, 2006)

Send me email. My PM box fills up pretty quickly.


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