quark mini hissing sound

[yellow]

... I know there once has been a thread on this, but was not able to find it ...

I have a warm white 1*AA mini and just recently noticed a very slightly hissing in low and medium (with LSD cell).
Just read about use of 14500 (not recommended) and tried one. The hiss is now very obvious. In low but especially in medium really noticeable.

with the Ni-Mh I thought about the current needed to ramp up the power, but with the 14500?
And why no sound at all in high?
:thinking:

Has there any solution been found to stop the hiss?

 

[DigMe]

I think it's a form of inductor whine. I could be wrong. I've noticed a similar sound a couple of times from my Preon.

brad

 

[AnAppleSnail]

... I know there once has been a thread on this, but was not able to find it ...

I have a warm white 1*AA mini and just recently noticed a very slightly hissing in low and medium (with LSD cell).
Just read about use of 14500 (not recommended) and tried one. The hiss is now very obvious. In low but especially in medium really noticeable.

with the Ni-Mh I thought about the current needed to ramp up the power, but with the 14500?
And why no sound at all in high?
:thinking:

Has there any solution been found to stop the hiss?

I'm pretty sure that the hiss is from PWM, not the voltage boost. I think 4sevens replaces ones with ugly hisses.

 

[effulgentOne]

Yeah, that's inductor whine, and it is related to the PWM dimming. My EX10 does the same thing, with the frequency changing as you ramp up/down in brightness. I have also observer that it's silent on high, and that it varies based on battery type (and how low the battery is).

Some inductors whine when switching back and forth between low and high power states (only necessary when dimming) but I am not enough on an EE to give a detailed description of why this is. It is also much more noticeable to young ears, as people lose their sensitivity to very high frequency noise as they age.