Does your LionHeart Hum?

Does your LionHeart Hum?

Mine does. On levels 2-3-4, I hear a hum, guessing about 800-1000Hz.
It must be in a very quiet environment and with the light near my ears. (if I set it on my vanity it is quite loud. resonant freq./Q?)
Might be the IC used to PWM the current.
/ubbthreads/images/graemlins/thinking.gif
Seriously...it does..I am not losing it! /ubbthreads/images/graemlins/icon3.gif

The Eternlight EliteMax (regulated) hums at certain output levels too. I think it's the coils in a small transformer that are flexing slightly in sync with the current passing through them. It's a magnetic effect. I think the term is magnetostriction or something like that.

It's normal. I think /ubbthreads/images/graemlins/thinking.gif
Gotta be the switcher circuit.

I havent noticed mine making any noises but i rarely use it.

Shane

I use both of mine nightly and didn't notice any noise. However, mine are usually on at almost minimum levels, so that maybe the difference.

Yep, I noticed the humming at a fairly dim setting.(maybe 20% brightness). Probably a resonance frequency as it was louder set on a hard surface in candle mode.

The tail end coil spring magnifies it...resonates at about 750Hz, in fact - "The Lion *roars*..."

Mine "roars" louder with the washer than the spring. /ubbthreads/images/graemlins/grin.gif
Thanks for confirming that I am not completly insane! /ubbthreads/images/graemlins/naughty.gif

Magnetostriction:

http://www.google.com/search?hl=en&q=define%3Amagnetostriction

Slight changes in the dimensions of iron or steel components resulting from changes in the magnetic fields acting on these components.

www.vibrationandshock.com/glossary.htm

Change in dimension by certain materials when magnetized

www.aimglobal.org/technologies/card/msglossary.htm

1. The phenomenon wherein ferromagnetic materials experience an elastic strain when subjected to an external magnetic field.

http://ctd.grc.nasa.gov/dictionary/m.html

(noun) A physical phenomena in which ferromagnetic materials are affected by a magnetic field. A magnetostrictive transducer has a magnetostrictive core material surrounded by an electrical coil. When current is caused to pass through the electrical coil a magnetic field is created and the core magnetostrictive material changes shape. Has been infrequently used as a stimulating element for ink jet systems.

www.trident-itw.com/resource-center/glossary.html

I'm guessing that this energy would easily find it's way into a nearby AM radio. Sometimes I use an AM radio as a quick check to see if an oscillator is, well, oscillating.