Grow tent setup

Afternoon all.

I have been hearing alot of talk lately (last 2-3 months) about fan speed controllers and their ability to burnt out near new or burn you fan out. I have heard this from 2 different hydro shops and thru a mate last week aswell when discussing my new fan filter setup. Has any body else heard of this or are these isolated incidents probably. I was going to go fan speed controller on my new 500cfm fan but want a bit of feedback and also does anybody run no fan speed controller and or just silencers (is a fan spd cntrlr better for odour control,I mean when you turn fan speed down do you not lower its scrubbing qualities?) If no go on the fan speed controller I was thinking of 2 silencers for fan noise. a silencer after filter into fan then from back of fan another silencer then into ducting as I don't want noise or smell.

Thanks people

i have a variac speed controller and i think its great never had no problems with it or fan.you have to turn it up/down your self but i only turn it down when in bed. my friend has a sms twin fan controller which controls temps for him but does make slight humming when turning fan down but he like it.i have acoustic ducting also plus silencer.