Rerurn to Romy the Cat's Site
In the Forum: Audio Discussions
In the Thread: It’s mad, mad, mad... electricity.
Post Subject: "Ground" vs. "Ground"Posted by Paul S on: 11/8/2020
On any USA electrical wiring system, ALL circuits are referenced to and mechanically connected directly to a common ground at all times via the "neutral" wire, which ultimately connects to the grounded bus in the service box. And all UL electronics are also connected to the house ground via their internal neutral wire. What is commonly referred to as the "ground wire" is a safety wire that safely drains away stray voltage from an appliance or circuit. When there is current passing between the neutral wire and the ground wire, there is a "ground loop", and when this happens in a gain circuit, there is vibration, heat and/or noise. The problems we have with noise in hi-fi are so myriad that covering the subject could fill a very confusing book. Basically, the Star Ground we talk about is a theoretical ideal and reference point, and it's not something that happens very often in a typical hi-fi system. In my own system I have everything tied back to the amps via RCA jacks, and all safety grounds are lifted, leaving the neutral wire alone to ground the circuitry. I also have to "bleed" stray current from my phono stage via a dedicated ground rod that is "not tied" to the main service ground bus or UFER. I put that in quotes because the component chasses are always electrically joined if all the components are designed around a star ground to begin with.
Don't I remember that the PP dirtied the neutral and the ground wire, as well? This would suggest an all-or-nothing scenario, creating a need to plug everything hi-fi that draws electricity into the PP. It might also mean the PP is "quietest" when its own safety ground is lifted, at least if it's built around a star ground. I can use a battery to power my DAC without a loop, but, again, it is yet referenced and tied to ground via the ICs. I absolutely need "correct" IC shielding between my SUT and my phono stage. For reasons I still don't understand, I once grounded this IC shield to my phono bleeder with good results. But now, my Placette-made ICs that do that link now apparently have "integral shielding" that grounds to the outer RCA connectors at both ends.
The Big Issue with the phono stage is the combination of wide-band sensitivity and high gain. If there is stray current in that loop, whether voltage or EMF, it will be amplified, and you're gonna hear it.
Best regards,
Paul SRerurn to Romy the Cat's Site