how to adjust fan voltage/speed micro grow

Hi I am currantly making a growbox out of an old tube amp i had kicking around my room. i have some computer fans for exaust and intake and a cell phone battery charger, but i would like to rig up my fans so i can adjust the speed and set it to the right speed so it is as quiet as needed. i have been exparimenting with different voltage battery chargers with my pc fans and what i have decided i needed is something so i canchange speed easily. i have some pots (like knobs that you turn on amp) and i was wondering if i rigged it up to that if it would work?

can anyone please help me?

The only way i would see is go get a multivoltage transformer from radio shack, the ones you can do 1.5v, 3v, 4.5v etc. Otherwise you have to get a 120 fan and speed controller. You do not want to try to lower the voltage to the transformer though, you will ruin it, just the voltage to the fan.

i tried hooking it up onto the volume pot controller already on the amp and it works perfectly! all i did was hook up the negative wire on the fan to the negative wire on the 9volt cell phone charger, and the postive wire on the charger and the fan to prongs on the pots and plugged it in. now from turning the volume on the amp i can controlle my fan speed im so happy

That was good thinking, surprised the controller is that sensitive, but if it works awesome, and you have done it "properly" in my book, shouldn't wear out anything.