Home studio mains/earthing questions.

[ni-cad]

Hello.

I have some concerns about the mains supply in my house specifically the earth networks running to my home studio which consists of various types of mixing & recording equipment, I'm looking for possible routs in to my recording systems that may either pick up or cause unwanted noise and this is where I need advice. Depending on what you guys think, I may hire an electrician to help me isolate some important units like my desk and monitors but I don't know at this stage exactly what I'm dealing with and until I can replicate for myself some examples of similar interference I'm a little reluctant to call someone in.

Firstly how likely is it for an audio signal to travel across a household earth network or be picked up by another piece of equipment further along on that same mains system by say speakers or a mixing board being used elsewhere in the house? Could an audio signal be deliberately routed via a household earth network in this way? I really don't know the first thing about this kind of stuff so please forgive my ignorance on this subject, I am assuming an earth wire could act exactly like a speaker wire does and carry audio signals just as well, please feel free to tell me if I'm making assumptions.

My other worry is that an earth system running the expanse of an entire house could act like a giant radio antenna, channeling unwanted noise and chatter directly to any equipment also using that same earth, considering this it would be interesting to find a way to monitor the earth wiring somehow to check for different types of interference, one way perhaps being to use an old speaker deliberately wired in to the mains earth? This got me thinking if a speaker could be wired directly to a wall sockets earth by literally fitting a plug to the end of the speaker cable and plugging it in, could I not then also connect a low powered amp to a different socket sharing that same earth so sending audio along the earth to the speaker? Forgive me if this sounds a little out there but I need to know.

Please feel free to give me your thoughts.

 

[BradtheRad]

* Earth ground is a bad bet for carrying signals (as either the send or return path). Best to use shielded cables for all signals.

* Balanced is better than unbalanced.

* Maintain more than an inch distance between wires which carry signals, and wires which carry house current.

* It's possible, but too risky, to use the neutral wire of the house AC for carrying audio or video (either to send or return). It also violates the preceding item.

* Ground loops are one thing you want to avoid. These cause hum in equipment. There are safeguards you can use to get around them. Nevertheless the more complex your setup, the more likely they are to pop up.

* A long wire does indeed become an antenna for radio signals. Then somewhere a diode can act as a detector. It's not unknown for a local AM station to be heard through a guitar amplifier.

* A long wire also links inductively to any local lightning bolt traveling in parallel. This can induce a massive current surge which may knock out equipment.

 

[FvM]

- all studio wall sockets should be supplied form the same switchboard, all PE wires should be star connected to this switchboard

- with correctly designed equipment, there's no earthing problem

 

[thannara123]

can you post a photo of your studio .