On 25 Feb 2007 11:50:21 -0800, "Bendzh"
wrote:
I did think of the transformer, but wouldn't the sound be coming from
there rather than the head in that case? Or maybe the fluctuating
current induces buzzing in the head?


The current to the bulb is 12V AC (alternating current) so it is
capable of causing buzzing at 50Hz.