Comparing Ripple measured on Opple 3, of Emisar D2 (dual channel LiIon only), D3AA and KR1AA:
bottom right is KR1AA using almost full PWM at 1 lm on LiIon
Overall the D3AA has the lowest Ripple when using Eneloop, followed by the D2 on LiIon.
The D2 actually has slightly lower Ripple than the D3AA on LiIon.
The KR1AA has the worst Ripple, on both LiIon and Eneloop.
i had a feeling…guess my eyes do still work somewhat after all. Sunlight has been doing something similar for a little while now, but at a shallower PDM, and because it’s so darn bright and pervasive, plus atmo aberrations, it’s hard to see. But it’s there.
yes.. light sources do Flicker, or Ripple (the generic term PWM is sometimes used, but technically PWM is a very specific type of Flicker..)
I was noticing the Flicker on my KR1AA when I got up early this morning… I had LiIon in the light and was using a very low output.. Ive now changed it to Eneloop to reduce the visible Flicker..
yah lol…When I first got my D3aa, I noticed it right away, but it was more like novatac’s PDM, or a very shallow flicker. Most flicker/ripple has the same dulling effect to my eyes, it just feels like an unnatural kind of dim, almost like a nanoshimmer film or filter…it’s hard to spot with multiple apparent sources, like I mentioned with sunlight…every intense ray from every apparent transmutive “source” (i.e. frosted glass, diffusers, layered fog) makes it harder to detect. That plus all the refraction and diffraction…it’s like a veritible light blender.
agree.. there are a lot of variables that affect a source to cause Flicker.. often Im unsure if its really there, or my old eyes are playing tricks on me (both are true.. lol)
however, with an Opple it is really easy to quantify the changes in brightness.. and even to watch the lux change in real time.. light is not a constant intensity.. its more like waves that pulse at varying frequencies and amplitudes.
The KR1AA has noticeably more “stormy weather” than the D3AA..
Im having fun comparing them 
My second KR1AA is out for delivery today! It will give me a chance to compare the beam spread of an NTG50 to an SFT70…
Most people will understand the definition but not the concept…light is interdimensional in nature lol
How hard did you have to look to find this?
I just tested a KR1AA with li-ion and Eneloop, and I was able to see the flicker on li-ion at around 1 lm w/ a NTG 4200K LED, but the entire rest of the ramp was smooth. It looks like it only produces visible flicker in one specific, narrow part of the ramp (roughly 1 lm), and not at any other level, and only with li-ion as a power source.
Also, do you notice any zig-zag in the ramp when it changes “gears” in the middle? I see a mild zig on mine, and I’m not sure if it’s a fluke or if I should adjust the ramp. I’ll fix it on mine regardless, but I don’t have enough hardware to determine if it’s common.
both samples I had exhibited the gear change blip. it’s more pronounced on the NTG 4200k version, visually, it’s very noticeable. It’s more than a lumen’s worth of jump.
I, too, get the same little blip. SFT-70 3000K.
My KR1AA seems pretty well behaved. SFT-70, 3000K. I don’t notice any flicker. I can’t say it’s not there, just that I don’t notice it.
What it does have is small preflash, a dip in the middle of the ramp (similiar to to the older Anduril lights when they were switching from regulated to direct drive if my terminology is correct), and a post flash where the main LED turns off, then back on, then back off.
I was using ceiling bounce before dawn at about 0.5 lm on liion.. I was not looking for it intentionally it just was just noticeable to my waking eyes in a dark room.
The lux fluctuations also show on my Opple 3 when Im using it in light meter mode (to check CCT and CRI). Outputs tend to hunt around a few lux.. its a pretty small range of change.. just 2-4 lux variation. This happens with other lights also.
yes it has the normal blip when ramping up past about 15 lumens.. I tried a few times to stop the ramp when I see the blip and the light is at about 20 lumens after I let go of the switch. Im used to that blip.. it is normal for my D3AA also (its closer to 10 lm on that model).
The blip is just a normal “personality trait” of my thefreeman driver lights, that I have gotten used to and dont expect to change ;-). The blip just informs me when I ramp above 10-20 lumens.
In other flashy news:
Curiously, the KR1AA, PostFlashes when turning off at floor. AccurateJazz has a video showing it in this thread. (fwiw, the PostFlash seems to go away when I disable smooth steps). This KR1AA PostFlash is the opposite of the PreFlash the D3AA has when turning on near minimum floor.
These lights just have a “flashy personality” lol. I accept them with their “character traits” and overall enjoy them greatly. These are not things I expect to change.
Hmm. Sounds like the mid-ramp blip is common.
It happens due to slight mismatches between the expected gear ratio and the actual gear ratio. If it’s consistent, I can fix it in firmware. If it’s inconsistent, it’ll be random chance whether a particular light has a mid-ramp blip or not. Regardless, I’ll update the firmware to make that particular step a little bigger, so hopefully it won’t zig-zag. A zig-zag looks worse than a bump.
The current calibration produces a totally smooth ramp on my D3AA and DW3AA, but I see a zig-zag on KR1AA. Not sure if there’s a difference between the two drivers which causes it, or if newer production batches have slightly different parts, or if it’s just luck of the draw. It’s the sort of thing which needs many data points to really determine the range of variability.
As for pre-flash / post-flash, that’s a hardware-level thing that I can’t really do much about. However, I hear thefreeman has been working on it and came up with a solution. So we probably have that to look forward to on newer drivers at some point in the future.
Im not clear on the difference.. I can live with it as is..but open to reflashing
A ramp “bump” in this case is when one of the steps is too big. Like, when it changes “gears” halfway up, the visual brightness might go…
The sudden jump from 4 to 7 isn’t ideal, but it usually isn’t very eye-catching.
A ramp “zigzag” is when one of the steps goes in the wrong direction. The gear change would then look more like…
The repeated “3, 4, 3, 4” part usually will be very noticeable visually.
Ideally, of course, it should go “1, 2, 3, 4, 5, 6, 7, 8”. But if there is going to be random hardware variation in the gear ratios, a clean invisible gear change might not always be possible. So I try to err on the side of having a “bump” on some lights, instead of having a “zigzag”. It’s better for that step up to be too high instead of too low.
Given a choice between a +2 “bump” or a -2 “zigzag”, I’d rather have a “bump”.
bump preferred for sure. at least its progression and not regression…will link a video to the behavior on mine shortly.
You can see the blips visibly blow out the camera’s exposure for a split moment, lol…
