Virtually all dimmers are build around SCRs and Triacs and what they do, in effect, is turn the switch on and off really, really fast. Since conventional incandescent lights have a filament that doesn't respond that fast, the filament sort of averages the actual power its getting.
But, some other lights, like flourescents and halogens, don't like being switched on and off like that. I had a set of LV halogens on a dimmer in my dining room that made a huge racket when the dimmer was used. I replaced that dimmer with one meant to control halogens, and its been fine.
But, be aware that switching things on and off like that really fast really messes with the AC in your house. Most audiofools won't have a dimmer in the same circuit (even the same house) as a decent stereo. While newer dimmers may control noise coming from the switch somewhat, just be aware they are still (unless things have undergone some radical redesign I wasn't aware of) going to create ugly noise on your AC lines. You will hear that on your stereo.
Besides, dimmers don't work well with compact flourescents. You have changed to cheaper, more eco-friendly CFLs, right?
