I am going to buy a 400 Watt HPS, and I was wondering how loud the ballast will hum on a normal and how loud it will hum on a digital. Also, about how hot it will get for each model. Thanks!
It's not going to be extremely loud but you will be able to hear it if you're in the same room with it. Digital will be a good deal quieter. Coil and core (older style) gets pretty darn hot and digital put out very little. I don't have any exact numbers though.
I have the old style and the casing gets really hot, the noise isnt noticable over my fans but if they are off you can hear a slight buzz. Planning on switching to digital after I save some money.