Originally Posted by goose134
Are you saying that the dimmer is buzzing or the lamps?
Goose asks an excellent question here.
The usual complaint is that the lights themselves buzz or ring, the noise being amplified as the lamp is made dimmer. As the dimmer is adjusted to provide less than full brightness, a triac inside is chopping portions of the AC cycles (for ease of understanding, you can think of the triac as an electrically-controlled switch). Essentially, a portion of each 1/2 cycle is removed which effectively changes the amount of power delivered to the bulb; the greater the amount removed from each, the dimmer the bulb. Unfortunately, chopping the cycle can cause the filament to vibrate.
That being said, better dimmers typically have chokes to smooth out the current during each partial half-cycle and minimize the buzzing/ringing of the filaments. If your noise is coming from the bulb, I'd recommend replacement of the dimmer. On the other hand, all incandescent bulbs are not equal. Subtle differences in the physical construction/support of the filaments (quality) among even standard-duty bulbs can be a factor. However, I would simply vote for replacement of the dimmer itself.
Now, understanding that there is a choke in the dimmer, it can be possible for the coil to vibrate and generate noise. Usually the wires of the choke are covered in a shellac which prevents movement and the choke itself is often potted in the switch to prevent this. This isn't nearly as common as the filament in the bulb creating the noise but I have seen at least two instances where the switch was actually making all the racket. Again, if this is the problem, replace the switch.
I have had great success over the years with Lutron dimmers. I find them to be reasonably priced and readily available. 2-cents, for whatever it's worth!