I second the recommendation to upgrade your dimmer. Lutron makes a number of high quality wall box installable dimmers. I use 11 of their Diva Series units in my home. Even when they are all on, no hum. Other problematic items are diode (capslite) bulbs, anything with a high/low switch that uses a diode (will drive class b amps (usually subwoofer) crazy).
Another suggestions would be to use a different line to supply the audio system (or dimmer). Best would be a seperate dedicated audio line. Use a very low wattage bulb with no dimmer. Or if you want the ultimate no noise dimmer, replace the dimmer with a variac (variable autotransformer). They don't install cheap, but are silent.
Another suggestions would be to use a different line to supply the audio system (or dimmer). Best would be a seperate dedicated audio line. Use a very low wattage bulb with no dimmer. Or if you want the ultimate no noise dimmer, replace the dimmer with a variac (variable autotransformer). They don't install cheap, but are silent.