Interesting observation on the KL1

This may well be common knowledge, but I noticed that the KL1 head emits a faint buzz when it is on. Makes me imagine that in 10 seconds the whole thing will self destruct.

What causes the buzz?

braindoc

The buzz is caused by the electronics inside the KL1. Some A2's do the same thing, if you do a search there have been a few posts on this A2 "noise" over the last few years.

Also, some people's hearing seems to make it much easier for them to notice these sounds. Kind of like how some people can 'hear' when a TV is on and some can't.

When you pass a strong, high frequency signal through an electronic component, like an inductor, the current (or its associated high-frequency magnetic field) may jerk it around physically enough to produce a sound.

I used to have a modem (a modem? what's that? yes, a long time ago) that did NOT have a speaker or tiny piezoelectric transducer, but when a call came in at night, when it was very quiet, I could here the screaming answer tone and response noise. Some component on there was vibrating.

There's a word for it.. what is it? Is it "electrophonics" ? something like that?

L2 does it on low. HDSs do it too

It's a common Occurrence, amongst Flashlights with electronic boost/regulator circuits

I hear it on the Surefire L2 on low only.

Funny, my A2 is completely quiet (than again, my hearing isn't what it used to be). I remember one of the other technicians at an electronic repair shop where I used to work fixing a big stereo system. He would disconnect the speakers and turn the volume way up and you could hear the music actually come out of the amplifier transistors! He told me that if you kept it up like that for long that it would burn up the amplifier section. I believed him!

My L2 makes quite a loud buzzing sound. I can hear it even when the flashlight is a good 2-3 feet away from my ears.

The buzzing is absolutely normal operation. It should not happen at all with fresh batteries. It tends to get louder as the voltage/current drops to the point just before the light goes out of regulation. The buzzing should be loudest just before it drops out of regulation. The harder the boost circuit has to work to maintain regulation, the more the inductors in the boost circuit will buzz. When the light's voltage/current gets too low for the regulation to work and it drops out of regulation(or the selected level of output on the light is set below regulation level as with HDS lights or other multi-level lights), the buzzing goes away.

My E1L doesn't make a sound at all when it is turned on.

Galiphrey said:

When you pass a strong, high frequency signal through an electronic component, like an inductor, the current (or its associated high-frequency magnetic field) may jerk it around physically enough to produce a sound.

I used to have a modem (a modem? what's that? yes, a long time ago) that did NOT have a speaker or tiny piezoelectric transducer, but when a call came in at night, when it was very quiet, I could here the screaming answer tone and response noise. Some component on there was vibrating.

There's a word for it.. what is it? Is it "electrophonics" ? something like that?

Click to expand...

Galiphrey, "may jerk it around physically enough to produce a sound"
Can you simply epoxy or hotglue down the transistor, inductor, etc to make
it quiet?

TJZ said:

Galiphrey, "may jerk it around physically enough to produce a sound"
Can you simply epoxy or hotglue down the transistor, inductor, etc to make
it quiet?

Click to expand...

Yes. (unless it's something that _supposed_ to move, like a switch.)