revoltec 3,5" controller strange noise
 

hi!

i just got a new revoltec 3,5" fan controller. i plugged it in and i think there is a small problem with it.

(a little intro here)
i have 4 fans in my case (gpu 60 mm - a zalman clone called pentagram, front - kama bay 120 mm, rear - an 80 mm arctic cooling, and an 80 mm coolink front bottom to blow over hdd and into nb heatsink). the gpu fan and rear fan were controlled with fan controllers in the back of the case (one controller per one fan). these old controllers allow to feed 5 - 12 v and work perfectly fine all this voltage range, but make me dive under my desk each time i want to up or down the speed (up when gaming, down when idle). the front kama bay and coolink are v low speed and i didn't need to slow them more.

so, after a lot of searching i found this blue (matches my white/blue case) revoltec controller with four knobs highlighted with red LEDs, bought it, got it today and immediatelly installed.

when i connected my 4 fans to it, they all started to make irritating sound when i lowered their rpm just a little below max. actually, only when on max rpm (12 v) they don't make the strange and annoying sound (sth like high pitch buzzing, like a fly or a bee). i've never heard this sound before from any fan on any speed. and it certainly didn't happen with my old back-mounted controllers. the sound ceases only when the knobs are set to max. when turned down just a wee bit - it starts again. when at minimum, just the same. i tried plugging the fans in different configurations, all at once, one by one and so on.

also, the red LEDs are supposed to fade when the voltage is set to low - but they don't. maybe that's supposed to means sth? ( i don't care about the LEDs, i don't need them, but they seem OOO as well).

oh, the revoltec thing supplies 7 - 12 v (not 5 - 12v!)

once again - the fans are ok, perfect when working just pluged to the mobo or with the back controllers.

has any one of you had this kind of problem before? have you heard about it?

or maybe you know what causes it because you deal w electronics and such? (i'm no good with electronics, don't even have a soldering iron)

thank you for any advice that you could have for me!