Joel, it's possible that your coworker, regardless of whether he's an "audiophile", isn't adequately informed on this topic. Audio equipment such as amplifiers have to have built-in provisions for power conditioning in their power supply section. The transformer, rectifier and filter capacitors take the AC from the wall outlet and convert it into clean DC for the amplifying section to work with. No additional conditioning is necessary with typical correctly designed units, although there're plenty of sellers out there who're happy to profit from the gullibility of some in this matter.
