And chances are you want to get rid of it, fast!
Buzz vs. Hum
Buzz and Hum are different.
They sound different, and they have different causes.
This means that fixing them may require different solutions.
Buzz is often a higher pitched noise that can even crackle at times. (Imagine the zzzzzzz and crackle in a bad AM radio station.)
Hum tends to sound lower pitched and it will likely have a tone signature that you can actually hum along with. (Imagine a low or mid-frequency mmmmmm.)
Finding & Fixing Buzz