I got a response email right after my request that it would be shipped 'soon', that was 9 days ago. Nothing on the doormat yet.
Well I know nothing about this company but in general, “large companies” are plenty well equipt to look out for themselves, and while it is true the the first unit of anything mass produced (fully burdened, assuming that indirect costs are applied tothe first unit as direct) is unbelievably expensive. #2 is not so bad.
Also consider that they are making a sales list of prospects, I am sure they dont assume to know the name of every eingineer who is developing a potential product for them to supply components for. “samples” are typicaly accounted for as a sales expense.
Also they probily allready have them packedged in sets of 10 and it may “cost” more for them to open a package and remove parts reseal the package and then have loose ones around. Where with the package request Shipping might be the first folks to actually “handel” the package.
$.01 worth
I got 5 XHP50 and 5 XHP70 Sinkpads in the mail today. :bigsmile:
That’s what I ordered, 5 and 5, and got an email response from them right after I ordered. They will be shipped to my old business which is a Restoration company.
They probably came today, I will check tomorrow.
Ok I jumped the gun a bit, the sinkpad samples arrived today. Great stuff! 
I got 6xhp70 coppers, 1xhp70 alu and the rest a mix of copper and alu xhp50 stars.
—
First impressions:
I don’t like the tiny traces they used to accommodate the 6v/12v configuration on these stars. They’re really wimpy and even in the 6v config much longer than they should be.
As we’ll likely never need to run these LEDs at anything other than the 6v config in a flashlight, that makes these traces an unnecessary complication.
Shorting the LED pads out with copper strips soldered across and running 10Amps through in the 6v Config I measured a 0.124v drop across the traces!
That works out to a resistance of 0.0124Ohm, really not great. We wouldn’t touch a DD mosfet with that high of a resistance for example.
at 15A it’s 194mv
at 20A it’s 285mv (you know someone will run 20amps through one of these suckers soon enough! 
)
Based on this, I’d say stick with the MKR variant sinkpads (only 6v compatible) or wait for a 6v optimized noctigon with beefy traces.
Cheers
Linus
This is off topic, but this is why even with the best of meters and short heavy gauge test leads, it is impossible to get accurate current reading of the draw on these high amp lights. Those meters use a 0.01 ohm shunt resistor. Much voltage is dropped across it and effecting greatly the actual current draw during the reading. These LEDs are greatly affected by that slight voltage drop and why I posted about that 0.001 ohm external current shunt.
Yes good point, standard multimeters really shouldn’t be used to measure high current accurately. Best thing you can do is measure current and output at the same time, then just output in the assembled light. If there are any differences in the measured output then that would show a false current reading.
I use a Turnigy 100A watt meter that has a 0.001ohm internal shunt and beefy 6mm bullet connectors but even then I still have to take it’s influence into account.
Received mine today, mere 10 days after ordering. Regular envelope, 3xXHP70, 1xXHP50; $3.23 to Germany.
Took some macros:
http://i.imgur.com/WrsF2Ek.jpg
http://i.imgur.com/NN5DEyE.jpg
http://i.imgur.com/I1BhEaY.jpg
http://i.imgur.com/aZdKBcF.jpg
http://i.imgur.com/UfjzkyA.jpg
http://i.imgur.com/a5NqADI.jpg
http://i.imgur.com/R091DBp.jpg
http://i.imgur.com/Cmv8WdO.jpg
Did you pay for them?
The thermal pad cutout looks ruff? How is te level difference between electrical and thermal pads?
These are not punched on the back like the old sinkpads, so there is quite a cavity that needs to be filled with solder on the thermal pad.
It’s basically like when we scrape the dielectric layer off cheap copper pcbs and have a hole to fill underneath the emitter.
They claim there’s very little difference in performance but I think there’s more of a chance to mess up a reflow for us by not applying enough solder to fill the gap. I dunno if that’s really a problem in practice, but I don’t like it.
Has anyone considered using a piece of Cu foil to fill the divot instead of a pool of solder?
Also even easier would be to use 96% silver solder, that should be even better than Cu foil since there’s only two material transitions then (LED to silver solder, silver solder to Cu MCPCB). With a piece of Cu foil there would be four (led to solder, solder to Cu foil, foil to solder, solder to MCPCB). Even if you had the foil pressed against one of the two (LED or MCPCB) there would still be those 2 additional transitions. Seams like silver solder will be the best method for dealing with MCPCB’s manufactured like this (or cheap ones we scrape).
From looking at the recommended solder pads for XM vs XPH50 it looks like you could just use an XM Noctogon or SinkPad with a Zener mod driver for 6V use. I’m thinking of trying this out since I never loaded the XM pill for last years contest light due to lack of a potent enough 2-cell driver. Would love to get one in an F4.
I also don’t like the new style pads from the picture, maybe I have to order one to check it out with my own eyes maybe it’s not so bad like it looks…
Doesnt the xhp70 in 6 V application fit on a mtg footprint too?
Put simply no. The MTG has a lot larger footprint. I have a XHP70 on an MTG copper star but it was a bit of work to make it happen.
Edit. The XHP70 is the same footprint as the MKR.
Does the 50 have the same hole in the beam as the 70?
No, they’re free samples.
I think it’s sintered. Looks smooth to the bare eye, unlike the base; although both feel smooth. The gap is quite big as in quite visible without magnification, not an optimal design. I don’t have any tools to measure its exact depth.
I don’t know what you mean by beam. If you mean the cutout, it seems like it’s a bit more shallow on the XHP50 version.
If you mean the +/- pad for the LED, this one is for XHP50 http://i.imgur.com/I1BhEaY.jpg and this one of the XPH70 variant http://i.imgur.com/Cmv8WdO.jpg.
yes, and it makes sense because the gap between the dies is the same.
Actually thought that only small companies would receive free samples, so I signed up - just because - why not …
Just received 10 sinkpads. Five copper XHP70 and five copper XHP50.
I feel a bit embarrassed, and obliged to start modding … :shy:
Sooooo … - I might just have to start a thread on suggestions/tips for which parts to buy :-p
…
Might even make a random.org giveaway on six of the sinkpads, as a thanks for the good reception here on BLF.
I also received a few 70 and 50 sinkpads. But I think they are not that good, while reflowing the coating turns brown very fast even if you keep the temperature low. Also the coating starts to get little cracks and the + and - pads are very easy to pull off.
Not so impressed 