weird noise with mh conversion bulb

i am installing the lights in my first grow room. i have a 600w hps digital ballast running a growbright 600w mh conversion bulb in an air cooled easycool reflector. i notice a high pitched whine coming from the bulb itself that isn't present with the hps bulb. the mh bulb also seems to run much hotter than the hps bulb. the little i have found in my brief search points to a bad bulb, and this bulb is brand new, not even an hour on it. any ideas? i thought i might not have seated the bulb fully, but i turned it until i was concerned about breaking the bulb itself and it seemed to seat like the hps bulb in that it got harder to turn about 1/4 to 1/2 turn before it seemed to stop turning at all. i didn't attempt to reseat it because i let the bulb warm up thinking it might go away, and the bulb itself is rather warm. any help i can get would be appreciated.

Get ahold of the place you bought your light at.I have not used a conversion bulb,but i have never heard anyone complain of one whining.OPH