Is it possible to get dimmer switches that don't buzz? We had these in our old house (fitted by qualified electrican). Now in new house and all teh dimmer switches buzz too. Is this usual or bad workmanship or bad switches? Also I have a one part (with dimmer) of a 2 way switch right by my head when I lay in bed which buzzes loudly. I was pretty thick to start with - do you think sleeping near the buzz is frying my brain too? This is a serious question!