[GB ended,discussion only] CRI > 80+ NICHIA 2000K-6500K [E21A/219B/219C/319A/144A/757GT-F1(Optisolis)]

I’ve seen that, but no 1*sm303 + 1*sm403 + 1*sm503 + 1*sm653 configuration :slight_smile:

:person_facepalming: how could I see only 403 and 503 in your post?
Anyway, CCT mixing can be predicted by simple mathematics. But you have to put output into the equation too. In an ideal case where all the emitters have exactly the same output and forward voltage, the resulting CCT would be very close to the average number. But unfortunately in your combo, each have different output. Sm303(D200), sm403(D200), sm503(D220), sm653(D240). Average them first then use the 200:200:220:240 ratio to approximate the resulting CCT

- Clemence

Thank you. So 3000*200/860+4000*200/860+5000*220/860+6500*240/860=4721K. Ideal :slight_smile: Order 10146 :wink:

Hi Damian,

Please specify the configuration as well. Use the LED config diagram in the product image
For example:
-LED1=303
-LED2=653
-LED3=403
-LED4=503

Wiring:
3V/6V/9V/12V

Thanks,
Clemence

Wiring would be 3V for both boards. About the led config… I don’t know, your example looks good enough. For the second - all 503. Thanks.

Got the 3K 4K and 5K nichias premounted on the quad boards. Had just a bit of time to light one of each, and definitely need more time because I am a bit confused about what I observe.

Just a quick question: Clemence what solder did you use on the contact plates? I had spent half an hour trying to solder wires to these plates and only half of them were eventually soldered securely enough. The rest just keep snaping off. The generic solder I’d used for years just would not adhere to the plates, I am really confused.

Are you using a high-wattage soldering iron with wide tip? The low thermal resistance of the dialectric means that the pcb is soaking up most of the heat from your soldering iron.

Correct, you have to apply a LOT of heat to mcpcb’s to get them to solder properly in most cases.

I usually solder around 380c but for mcpcb’s I crank it up to 450-500c depending on how large the mcpcb is.

I meant this specifcally for this pcb. Soldering the wires to it is much more difficult compared to normal DTP PCBs.

yeah, I was too, although it depends on which mcpcb you are talking about. The GT mcpcb is a special kind of difficult to solder wires to lol.

This is the first thing that came to my mind. I use a regulated iron which I set at 300C and when I kept it attached to the PCB for some time, the blob of solder did attach to the plate and looked like a normal blob. But then it just snapped off as if there was dirt underneath. Which was not since I used soldering acid that had worked every time before that.

I am not sure what wattage is this iron, but I used it with an attached aluminum plate for reflowing an LED on another board and it did it easily.

But OK, I’ll try higher temp. I think the iron can go up to 450C.

So far I am very happy with that single 3K. It does have some tint shift, but for a warm tint this is irrelevant.

The specific 5K I tried was a benchmark mule emitter. On par with my trusty 083 but with the potential for a much higher output. Just need to confirm the observation with the other three 5K LEDs on the board.

The one 4K I tried (out of four on the board) had bad tint shift, that nasty green corona which I hate in 219B/C. Not that much of it, but still unacceptable. This was so strikingly different from the 5K that I was really puzzled. But it looked like the tint shift was different in different directions, which may have to do with the remaining three unlit LEDs, reprocessing the light of the lit LED.

Regardless of the tint shift, the on-axis tint was excellent in all the CCTs. No green, no magenta, but I’ll need to double check this in a well illuminated ambient light conditions. My little workshop was not like that today.

So next thing will be to test the consistency of the tint shift patterns across the samples.

Yep, loads and loads of heat is needed. I even bought a new tip for my 80W iron especially for these virence boards.

Heh, Clemence you really ought to enclose an appropriate iron with every shipment :smiley:

Why dont you use fan? Nevertheless cheapest bekon 950d work good with this mcpcb

I’ve got a lot of CRI measurements from the E21As Clemence sent me here for those interested:

The results are very good. Super neutral on small currents, rosier on higher. CCT isn’t really affected.

These are all on-axis measurements for both bare leds and with a reflector, right?

What I find interesting is that with the reflector, the LEDs up to 4K keep their CCT while for the 5K and 6.5K LEDs the spot is ~500K cooler than the spill, which means that the tint shift in cooler LEDs is different from that of the warmer ones.

EDIT: what kind of sensor do you use? I have an x-bright i1, that came as part of my display calibration bundle, do you think is it the right tool for your kind of measurements?

Yep.

It’s an x-rite i1pro. You can measure tint (cct and duv, xy coordinates) with the i1 display (pro) colorimeter, but not the CRI, which requires spectral data from a spectrometer. I recommend using the Argyll tools, especially spotread.exe.

Thank you!

Taken from VR16S1 product page

NOTE:

  • For manual reflow we strongly suggest Pb63Sn37 solder paste. Poorer wetting of leadfree solder paste requires precise dispensing and LEDs placement.
  • The ultra thin solder mask/solder resist is somewhat fragile, especially in hot temperature during reflow process. Avoid any hard and sharp objects on it.
  • Solder mask is rated to survive multiple reflows up to 300°C only for a brief moment (< 30 seconds). Prolonged high temperature exposure above 240°C will make it less white while still functional
  • Soldering LED wire can be difficult because the board is very thermally conductive.
  • Fixes: Use more powerful solder iron with as big as possible tip, pre-heat the base (or the case/host), use intermediate wire (solder a short slave wire to the pad first).

Note: I successfuly solder all the boards using 30 watt solder iron with board temperature of 150C or...

200 watt solder iron at base temp of 100C. I use cheap Dekko 30 - 200 watt iron with big pointy (blunt) tip. My more expensive 20 - 130 watt Hakko Presto is too weak after I modified it to finer tip.

- Clemence

Thanks Maukka, I updated the product pictures using your charts. I hope at higher current the result would not differ by much.

- Clemence