Noise susceptibility (or the lack thereof) in audio systems is a function of two principal factors: shielding, and the “pin-1 problem.” The endless conversations concerning this matter inevitably involve earth “grounding,” a subject which has been around for so long (200+ years) that it has devolved into a sea of confusion, misinformation, and mythology, even though it is completely dictated by easily understandable basic physics.
Conventional grounding mythology would have one believe that electronic systems of all kinds must be robustly connected to earth ground in order to properly function – audio signal processing systems in particular. The grounding reality is that airplanes, motor vehicles, laptop computers, blasters, etc. seem to work just fine without connections to earth ground. Nevertheless, A/V systems of all kinds are considered exempt.
According to the conventional mythologists, “noise in audio systems must have something to do with grounding, what else could it be?” The bad news is that the short answer to this question would fill up this entire issue many times over. The good news is that on the Professional Sound website www.professional-sound.com, a long list of reference material will be found. In addition, the June 1995 issue of the Journal of the Audio Engineering Society, entitled “Shields and Grounds,” includes seven papers which directly address this matter. Go to www.aes.org, and look up “Special Publications.” It’s available as freeware to anyone for $15 US, less if you’re an AES Member … it may also be downloadable. It won’t take you long to realize that the conventional mythologitsts just might be wrong!
Neil Muncy has been around since the days when recorded sound was analog mono and vacuum tubes ruled the audio landscape. He has been a consultant in the audio field for many years, and can be contacted by email at: firstname.lastname@example.org.