There are no moving parts in EvoPrimer. Some coils can actualy produce sound, but EvoPrimer won't supply them with high enough power or low enough frequency to produce audible noise. So the only possible source of "buzzing" is audio subsystem. Have you tried switching the loudspeaker off (in Config->Interface), turning baseboard on without plug-in board? Maybe you can plug/unplug headphones, move around the house/city - in case of some kind of interference.
I experienced a "strange voices" and "hum" with Primer2. Turned out it was interference from one of AM radio stations. In Russia and east Ukraine it's a common problem.
