Buzz in my electronics
Can you isolate the problem to any specific lights? Of course, obvious question, but if all the lights are off does it go away? Does the buzzing get louder as you turn more lights on? 

It's possible that this is caused by older magnetic ballasts (which themselves typically buzz). You could try replacing just the ballasts with electronic ballasts, just be sure they are equivalent and pay attention to the difference in wiring. It may also mean that you need new bulbs, as you may not be able to find an electronic ballast with the same characteristics, but that's not maybe not terrible since T8 bulbs (1" diameter) are supposed to be better and more readily-available than T12 bulbs (1.5" diameter).