Noise from within

*Chapter 20 of my upcoming novel, Resurrection, is posted here. When we think of guarding our systems from the scourge of radiated noise we almost always assume it comes through our powerlines from outside: cell phones, televisions, our neighbors. Yet, the noise levels on power lines are actually not much to worry about. Perhaps the noisiest equipment in our homes comes from our stereo equipment and support products themselves. Here, just the act of converting AC to DC inside our audio products spews radiated noise at far higher levels than what's found in our walls. And then there's digital audio, switch-mode power supplies, small wall wart AC adapters for our phones—all sources of noise we would rather not have contaminating the pristine audio path we depend upon. Properly shielded power cables help, but few are "proper". The correct way to shield a power cable is when the manufacturer ties only one end of the outer shield to ground. A standard shielded cable acts more of an antenna than a shield. If you're unsure, ask the designer. If it's a stock power cable, no need. It's wrong. One thing I do is keep anything with a switch-mode supply as far away from the rest of the gear as possible. For example, in Music Room Two we depend on an iPad to access Qobuz and Tidal. The charger for that device is always plugged in and radiating. We do not think much about it, yet it's all the while spewing noise. The solution is simple. Just move it a foot or so away and you're good. Take care of invisible radiation coming from your equipment and the ancillary products associated with it. You'll be happier with your music.