Strange earthing needed

[appspark]

Hey all, i'm asking this for a friend who is building his own studio. This is not a uk install but finland.
Basically he's got/getting a 3 phase supply. Earth loops wreak havoc obviously with all the audio gear causing hums and other issues(offset of wafeforms another). His plan is to run all the audio gear from a single phase and keep that phase clear of all lighting and hvac. The 'holy grail' of studio wiring is to wire it in a star system so that all the audio earths are brought back to a single earthing point. his plan is to drive a spike into the ground and use this as the earth.
I suggested an isolating transformer off the top of my head a while ago and he looked into it but apparently eddy currents mess everything up.
So i'm wondering if this would work? Also what are our regs on spacing and placement of rods. We're trying to find the relevant regs in finland but language is hindering us a bit. If we find our regs we have a better chance of finding the relevant regs over there.
Thanks fr any help anyones got, i know its a bit of a specialised area.

 

[Darkwood]

What are you trying to achieve ... reduced interference, humming buzzing etc through the speakers...

Best bet is to go onto Audio sites and like into many devices that exist to reduce this interference like hum lifters, line filters etc ... the audio equipment has an habit of just picking up natural mains frequency when say you get a guitars pick up close to other electrical equipment - the pick-ups can become an antenna, harmonics are also an issue too, these give more of a buzz as you pick up multiple waveforms..

 

[UKMeterman]

Hi,
Clean earths are a bit of a myth, to reduce earth loops, you need to get the current down in the screen of any audio equipment, the best way to do this is provide a decent parrell path. The best hum reduction is actually decent screened cable, and the used of ballanced audio connections, have a chat with these people and don't skimp on the cable or connectors. Also keep any mains cables at least 30cm away from audio cable and double that distance for big transformers and so on. As well as the mains safety earth if anything hums try running a 4mm2 wire along side the cable run that is suspecting of causing the hum. Some more information here EMC Information Centre





As for where to buy kit and have some guidance have a look at Canford - Professional audio, video and broadcast equipment

 

[appspark]

He's just trying to stop any interference in the signal chain. It's actually an analogue mastering studio so no recording happening with instruments, just running through different outboard processors so any difference in earth really messes it up.
He's had a good look through all the forums but says most people seem a bit up their own backside and its hard to see the wood for the trees if you like.
Regarding cable and connectors it will only be VDC calbe and Neutrik connectors.
Also as a side bit of info, before my life as a (trainee)spark i was a live sound engineer, definitely know the need for a good screened cables, and trying to stick mic cables and power apart and only crossing at 90's etc.

 

[UKMeterman]

Hi,
Well in that case have a look at the EMC information center and follow the notes, and remember to provide an alternative path for any currents in the screen of any cable, and the screens need to be connected at both ends. If you have anything with a 2 pin plug then make provison if required to connect the case to case of the the next item in the chain.

 

[appspark]

Cheers ukmeterman. im sure he'l be running an earth round all his gear, this pro stuff usually comes with a separate lug for earthing, though its all going to be in 19 inch racks and that will have an earth aswell.
I'm really looking forward to seeing him finish(no pun intended) as he's built it slowly himself over the last 2/3 years, most of it in several feet of snow.
He's even found old PCB drawings for old out of commission gear that he liked the sound of and built the boards himself with only the best components.

 

[UKMeterman]

Also be aware of the leakage current from all the mains filters, each one can leak up to 3.5mA to earth, 3.5mA hurts, more than 10mA can be leathal, so need twin earth conductors to the supply earth from most 19" racks

 

[Lucien Nunes]

The choice of what to connect the star point to might not be as critical as you expect, because systems operating throughout at 0dBm line level are pretty tolerant. I have spent many years designing and installing analogue audio gear and IMO if you get the interconnect grounds right and avoid nasty loops and RF pickup hazards, it remains quiet even if your reference is not quite as clean as one would like.

Most of the problems I've encountered in the field stem from incorrect connection of balanced and unbalanced sources and destinations, high impedance outboard gear not properly matched into the system, and common-or-garden ground loops that could have been seen coming. Vintage tube gear is harder, you will encounter C/T transformer balancing, very high impedance unbalanced I/O and audio busses grounded in multiple locations, special care is required!