So I just received my second SWM C22C after gifting the first one (under much duress) to my Wife.
The first was from Banggood, received in May and is absolutely perfect.
The new one is from Gearbest, ordered in June after their stock issues, received on Monday, and is terrible!
The flashlight emits a very high pitched whine (constant frequency) when it is switched on.
You need speaker volume (and probably young hearing!) to hear the video:
In the video you will also hear my dog growl in the background when the noise happens. As the light was intended for use when taking him out for a walk (due to the round floor-focused emitter), it is pretty darn useless. He won’t come anywhere near when the light is on! I don't blame him - it even hurts my ears and gives me a head ache.
Front emitter causes the sound when in middle mode - 2 away from brightest.
Side emitter causes the sound when in brightest mode (loud) and second from brightest (less loud).
Both emitters on at the same time might cause all my windows to shatter simultaneously.
Didn't catch it in the video but just realised that Strobe mode makes it sound like disco too!
It is definitely not normal to be this loud and noticeable, even from a distance. My other one of the same model light is competely silent, even when placed up close to the ear.
Seems like it’s PWM noise used to dim the LED while on modes other than high at around 5kHz. I might be that you got a lemon with poor soldering with a bad connection that can cause the switching noise.
You might try requesting a replacement, but you’ll probably have to eat the return shipping costs. It’s interesting how much your dog hates the sound.
Mine has that noise too, getting the driver out is a piece of cake, just unscrew the back and thats it, what components should I put what in? glue silicon, potting compound, what?
Hmm this seems to be a common issue but I’m glad it’s easy to access the driver.
I’m not sure what exact component makes the high pitched whine, but I did notice that loose solder joints and connections exacerbate the noise. I’d double check for cold solder joints and then maybe pot the driver with a potting compound. That would make future modding and repairs pretty hard though.
I can assure everyone that I have already taken the torch to pieces before posting here...
Checked all the connections, no dry solder, no loose joints, no misplaced contacts, checked over both emitters, switch, driver, etc:
To me this is just as useless as if the actual LED lights didn't work at all. Seriously; not even the ambient outdoor noise masks the squealing sound, even at a full arms length. So annoying...and then the dog starts barking at it.
It does give me an idea for a double-tactical flashlight though that can assault both senses at the same time when in strobe mode
I moved the coil higher, checked all the joints, repositioned some of the fine copper coil-wrap, and isolated it with electrical tap away from making contact with the driver board or inside head/body. It didn't seem to make much difference.
Ho-o-o-o-owever here is something that seems to have helped A LITTLE...
I noticed some brown solder residue across the top of the MCPCB; tracing from the surface of the +'ve terminal (near the emitter), under the red wire, towards the host casing and under the PCB. It seems this was making some contact with the body.
The position is indicated in the photo, but this was taken AFTER I removed most of it. Sorry I didn't think of taking a photo before.
With a steady hand I scratched all the crust/solder residue (looked and felt a little like rust) off with a x-acto blade, being careful not to remove the PCB surface. Then I re-assembled and presto...
Noise is now VERY much reduced. It is still present if you listen carefully and close, but nowhere near as audible as it was.
Put it this way - the strobe no longer sounds like a beeping personal rape-alarm. And even better, the dog no longer growls when I change modes!
I hope this can help others who may also be experiencing similar. Do let us know.
I opened mine up and the led solder points were ok, I did tighten the MPCB to the board a little more and and closed it up, I then proceeded to open the driver and put GC Electronics Type 44 Heat Sink Compound on the coil as CRX sugested, and re assembled, I don’t hear the noise anymore. Solved! Thanks CRX!
Edit, there is still some noise in the driver but is barely audible, I can only hear it if I hold the light against my ear
My C22C has another problem. The turbo mode is actually lower than high mode on the front XM-L2 led. When switching modes it does only a small flicker when jump from turbo to high but I can barely see difference in output. And high is higher a tiny little bit than turbo. My amp draw was 2,75A in turbo when I got it but after two days it is 1,1A and high is 1,25A. Any idea?
I found that as battery dra8ns your lower modes are same level at full battery but higher modes get lower and lower. All C22C does this. Bad design that is all.
That is normal behaviour of linear and buck drivers. At some point and downwards the input voltage from the battery isn't enough to meet the emitter voltage at the given current for the higher modes; as the battery depletes lower and lower modes get affected, too.
