519A, Try Slicing!

Flashlight Modding and DIY Parts
1

I have several 519A emitters in various CCTs, all R9080.

I’ve tried them domed: They are OK. I prefer my sliced 351Ds in most cases. With the dome they are very close to neutral duv. I prefer a negative duv (but not too negative!) There is some spectral shift over angle in a reflector. Not bad, but not anything special either.

With the domed removed (very easy to do), I find the duv too low for my taste. The CCTs also drop too much as I prefer the 3500k to 5000k range (depending on flashlight type and usage).

Since I’ve had a lot of practice slicing 351Ds, I thought I would give that a shot. I also call it shaving, in case I use that term. With slicing, I get a good amount of duv reduction, and you can almost dial in the CCT!

For example, here is some data taken with an Opple LM Pro, in Wurkkos WK01 hosts. The Opple results may be off some, but the relative numbers match what I see. The WK01 is a AAA host, so drive currents are low. The slice thickness is the washer used, which represents mounted LED height after slice. For example, a 0.85mm slice is pretty much the height of the glass over the phosphor.

Data is formated:
Emitter, CCT measured, duv measured

519A 4500k domed, 4211k, 0.0002
519A 4500k 1.4mm slice, 4033k, –0.0023
519A 4500k 1.2mm slice, 3822k, –0.0021
519A 4500k 1.0mm slice, 3499k, –0.0028
519A 4500k dedomed, 3250k, –0.0045

519A 5000k domed, 4696k, –0.0008
519A 5000k 1.4mm slice, 4614k, –0.0042
519A 5000k 1.2mm slice, 4244k, –0.0040
519A 5000k 1.0mm slice, 4074k, –0.0038
519A 5000k dedomed, 3654k, –0.0057

519A 5700k domed, 5281k, –0.0024
519A 5700k 1.4mm slice, 5178k, –0.0056
519A 5700k 1.2mm slice, 4714k, –0.0048
519A 5700k 1.0mm slice, 4348k, –0.0037
519A 5700k dedomed, 3969k, –0.0053

There is some variation in the Opple numbers if you measure them several times, but the variation is smaller than the duv deltas I measure from domed to sliced, and sliced to dedomed.
The CCT changes also match what I see when compared to other emitters.

I see a similar trend with the other CCTs also (2700k, 3000k, 3500k, and 4000k), but don’t have the detailed data on them.
As a bonus, the CCT shift over angle is much better with any amount of slicing, especially once you get most of the round part of the dome off (~1.2mm slice).

I’ll be slicing most of my 519As.
Give it a try!

FB

4 Thanks
2

Good info, I’m interested to see the output difference between domed, different slicing height and dedomed.

3

I saw a hit with the first slice… about 15% (measured with ceiling bounce).
But not much further reduction, even with the dome completely removed.
This surprised me because it doesn’t match what I see with other emitters. These may act different because of the glass layer. It is another interface that impacts dispersed and reflected light.

The duv also doesn’t change much with slice thickness. It stays about the same (within Opple capability and my eyes). You get a reduction with the first slice, and another reduction with all silicone removed down to the glass.

Only the CCT changes significantly with slice thickness. You can dial in the CCT you desire w/o much impact to duv or output.
I really like the amount of duv reduction w/o much CCT drop, with a thick shave. The increase in throw and beam evenness is also a bonus.

I didn’t find them hard to slice either. But, I’ve been practicing on 351Ds for a while now.

I also experimented with “adding” silicone. I used a normal clear silicone caulk thinned with mineral spirits. I place a thin layer on the glass and let it cure. I got an increase in CCT of ~200k and a very small increase in duv (<0.0010). This was a 4500k emitter from Convoy. This result matches what I saw with the slicing tests, but is hard to control the thickness. I might try to add a little to some of the LEDs I sliced to 1.0mm to bring them back up in CCT a little.

FB

1 Thank
4

thanks for the data
seems my Opple reads about 7-12 higher duv than yours (suprisingly close imo):
our CCT values are very close on both domed and dedomed, (except the stock 5700K)

> 519A 4500k domed, 4211k, 0.0002
sliderOpple: 4250K, 0.0008

> 519A 4500k dedomed, 3250k, –0.0045
sliderOpple: 3400K –00036

> 519A 5700k domed, 5281k, –0.0024
sliderOpple: 5800K, –0.0012

> 519A 5700k dedomed, 3969k, –0.0053
sliderOpple: 4100K, –0.0042

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5

I’ve always suspected that my Opple reads low on CCT, especially above 5000k.

I haven’t dedomed or sliced other CCTs, but with dome on I get:

519A 2700k domed, 2660k, 0.0007

519A 3000k domed, 2993k, –0.0003

519A 3500k domed, 3423k, 0.0004

519A 4000k domed, 3779, 0.0009

FB

1 Thank
6

Hi FB. Thanks for the tests results. It looks like 519A has significantly tint shift over the angle. How do you think they compare to other emitters, like 219C, 219B,LH351D regarding tint shift?

7

I don’t have any numbers for angular tint shift on the emitters you mentioned.

I will say that I usually prefer reflectors (to TIRs) and tint shift is something I really dislike. Eyes can adjust to CCT and duv, but not if those things change within the same beam! This explains why the XPL HI is my favorite Cree emitter.

For angular shift, I would say the 519A is similar to the 219C and LH351D. It is not as good as the 219B.
The angular shift is better on the low CCTs and gets worse on the higher CCTs (like most emitters).

Shaving or dedoming the 519A gets rid of most of the angular shift (again, like it does with other emitters like the 351D), and will be my preference. I really recommend trying to shave (or slice) the 519A. A thick 1.2 - 1.4mm washer and sharp razor blade is all you need. This gives a good duv drop, a minimal CCT drop, and improved angular shift.

FB

1 Thank
8

Very good info FBsLights!

It’s amazing how transformable these 519As are.

9

Thanks. I’m considering replacing 219C 5700K for 519A 5700K. I do like 219C tint, but tint shift is particularly bad with the TIR I’m using. So I would also need to shave the 519A.
I already shaved lh351d. I’m wondering if it’s worth to order 519A to do it.
For measuring tint shift,I think you can take one measurement on hotspot and another one on spill.

10

Eh, I don’t think you need to get 519A LEDs if you’ve already got domeless/dedomed LEDs.

Side emitting enhancement silicone, especially domed ones, amplify by their nature any imperfect nature, and depending on the quality of the silicone used itself, it might cause further problems just by its addition.

11

I’ve done measurements in hotspot, corona, and spill. To my eyes, changes in CCT and duv both look bad. Especially if all three (hotspot, corona, spill) are significantly different.
The reflector/optic used can also make a big difference.

I just measured: 4000k 219c, 4000k 219b, LH351 5000k shaved, 519A domed and 519A shaved.

The domed 519A looked and measured the worst (not bad, but it is in good company).
The 219c and shaved LH351D were in the middle. These look good to me, even being picky on a white wall.
The best were the 219b and 519A shaved. These have very even CCT and duv.

FB

12

Thank you FB.

13

Like thefreeman’s LH351D slicing study, you just wrote the definitive guide to 519A slicing. This is a tremendous resource and one I’ve been hoping to see for a very long time.

14

What washer is needed for slicing?

15

Any type of metal washers should work. Ideally one that fits closely around the LED. And the washer should be smooth on the top so it shaves the dome off smoothly.

You can also sand the washer to make it smooth and to the thickness you want.

Here’s a custom one I made to shave down some SST-20 LEDs to just under 1mm:

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16

@NeutralFan, would you be willing to make some of these custom washers and sell them?

17

I appreciate the suggestion BlueSwordM, but my efforts was to meet a specific need that I had. I have lots of washers and parts, but not really for selling.

Probably the best option would be to visit your local hardware store.

Here’s a pic of some of my parts I used to modify a rock tumbler for my son:

1 Thank
18

Ah I see. Thanks for the response.

Could you measure the thickness of your washer at the point that is the closest to the LED? It’d be nice if I could source some similar washers to make some high CRI superthrowers :smiley:

19

Feeler gauges are much easier than washers.

20

Huh, I didn’t even know these kind of things existed.

Thank Bob_McBob.