Thank You for the excellent info, and spectrum data!
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Alright everyone, after many times of saying my KR1AAs haven’t had real issues, it caught up to me.
My KR1AA V1 is acting different, I believe the driver is on the way out. Moonlight/floor from levels/steps 1-16 have visible PWM now, and what is likely coil whine.
Factory Anduril steps 1-4 out of 7 make audible noise, each step has a different pitch, 2 being the loudest.
Step 1 sounds just like the low electrical hum of a sodium street lamp, with the worst PWM. It’s visible even without moving the light or your eyes.
Step 2 is quite loud, sounds like really bad squealing serpentine belt or almost like bad brakes. Screaming banshee type of thing.
Step 3 is very similar to 1, but higher pitch.
Step 4 is faint, but sounds like radio static to me.
Candle mode sounds like something possessed and currently resisting being exorcised.
My KR1AA V3 does not have any noticeable noise at all except on strobe, but that’s entirely normal AFAIK. The V3 also has absolutely zero detectible PWM.
I’ve been carrying my V1 KR1AA almost every day for the past week, only one day I carried the KR3 which also makes no audible noise.
This really started today as far as I can tell. I used it a lot yesterday and think I would’ve heard it more, but possibly it just wasn’t as loud as it is now. I use it on moonlight very often and definitely would’ve noticed this PWM. It’s a little worse than a TS10 V1 on moonlight.
I’ve taken some videos of the noise, but I don’t know where to post them here.
Is the inductor coil going out? New driver time?
sorry to hear that
first thing I would do is clean out all the old dirty lube..
then apply minimal new lube mainly on the O rings, and wipe off the ends of the body tubes and keeping the contact rings wiped clean
did cleaning make any difference?
Does the behavior change when using a battery charged to a different voltage?
The boost regulator changes its behavior depending on the input power and desired output power. Most of the time it’s pretty quiet and steady, but on some settings it can be loud and pulse-y… and the behavior depends on analog signals.
Cleaning the contacts may also change the behavior somewhat.
I’ve noticed some noise on almost every Lume-based driver I’ve tried, but it’s different on each individual light. Usually the easiest way I’ve found to hear it is to go to somewhere around level 30/150, then go to “smooth beacon” mode and put the light by my ear. It’ll usually click or chirp somewhere along its automatic ramp-up ramp-down cycle.
I don’t normally hear it during regular use, because the sound of clicking the button hides the sound of the regulator as it slides past a noisy level. But smooth beacon mode goes through those same levels without pressing the button, so it’s easier to hear.
Can’t say I’ve noticed it on a thefreeman driver like the kr1aa uses, but the regulator is similar so I’d expect similar behavior.
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You’ll need to put them on a third party host like YouTube.
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There’s a small zone of instability on the upper part of the lower ranges with MP343x based drivers (basically all boost drivers), if it’s too instable then it can generate audible noise, not visible flicker though cause it’s around 3~10kHz .
It is indeed affected by the input voltage (lower = more stable), outout voltage, the amount of output capacitance, and the value of the OpAmp compensation capacitor. The later being very effective at dealing with this instability but if it’s too high it makes the range/gear change more visible so there’s a compromise there.
On the D3AA i used a comp value that should be high enough to never cause audible noise. But while the KR1AA driver is based on my D3AA driver design, I didn’t make it, thus the value probably wasn’t tweaked for the different output voltage, so I don’t know if it’s good or not.
That said @Tankolai ’s driver is most definitely dying.
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The battery in it was a button top 2023 H10, around 3.8V. I tested the noise with a few different batteries and charge levels.
With 1.5V AA, I only hear the noise on level 2, and it’s more of a regular mid-high pitch electrical whine like on my TS22.
With 1.2V NiMH, I can just barely make out a slight noise with the light in my ear basically, same as level 2 Alkaline but almost not audible to me.
With a charged 4.19V Wurkkos 14500, noise is the same as the Vapcell H10 originally.
Skilhunt 800mAh at 3.6-7V protected 14500 changes it a can only hear levels 2 and 3. 2 sounds like the original post but with added TV static fuzziness, level 3 is really high pitch just like a CRT TV whine. I can only hear this from my right ear, the left I hear nothing which I’m interesting and unfortunate.
With another H10 but flat top at 3.3V, I can also only hear level 1 and 2, and they’re slightly different sounding yet again. Step 1 sounds like street light hum again, but with an even more fuzzy static noise. It is much quieter than the original H10.
Also, all of the same batteries tested in my V3 KR1AA with no sound audible to me except the slight clicking in strobe. No PWM I could tell.
Cleaning did not make a noticeable difference.
I did notice that the visible flickering on low level only happens on stepped mode. In smooth ramping it doesn’t do it.
It just started doing this: 1H from off goes to floor/moon, but within 1 second the emitter is not lighting up visibly. It is still on, since 1C from this and the AUX turns back on.
However if I 1H long enough to get to step 2, then go back down to step 1, it works properly. I did another factory reset after noticing this, and now the visible flickering is gone no matter what the floor level is set at.
Besides this and the noise the light works properly.
This light has been dropped a lot so maybe some component has come loose or something. I’ll try to get some spare drivers next time I order, I usually like to keep at least one spare on hand even though I can’t say I’ve ever had a Hank driver go out, only Acebeam, Wurkkos, and Convoy, however the convoy drivers were my fault cause noob soldering with a cheap iron, I’ve improved since.
Thanks all,
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