MH light buzz

[Constantin]

I am setting up a new system with 3x400w SE XM 10k powered by PFO HQI ballasts. One singe and one dual ballast.
I purchased the ballasts used, but all the bulbs are new, when I first set up the lights, there was no problem, however, a few hours later, there is buzz coming from just one of the bulbs - the one powered by the single ballast, what does that indicate? when testing out the bulbs with ballasts, I did not get the buzz, any idea?

Help is greatly appreciated!
Thanks!

 

[125G Reefer]

Metal Halides buzz. Nature of the beast. Not very loud mind you, but they will buzz some.

 

[floridareefer18]

just the juice there sucking, and your money. ahaha

 

[Constantin]

they dont buzz normally, i am talking about the actual light, not the ballast... the buzz i was talking about was VERY loud, however it seems to have gone away now, but i want to know what it was, because it still sometimes comes back, but on just one of the lights

 

[Fsurocks99]

I have the same problem w/ my 150w MH. Before I replaced the light, there was no buzz, but now there is and it too buzzes on and off. And the buzz also comes from the light and not the ballast.

 

[c2300]

I have the same situation when I use the bulb with the small black initiation inside. And the buzz sound is on and off.