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Acceptable Level Ground/Earth Noise

Hi Everyone
I have a dedicated earth for my audio system.  I was digging a bore for water and lost the rod so decided to dedicate that bore for Earth.  It is about 100 feet deep an is in water.  The line runs straight to my dedicated audio room and is shared among the various audio components.  
I am running a Clearaudio DC preformence through an Avid Phallus phone stage hooked up to a ML No.  38s pre.  The cartridge is a clear audio virtuoso MM.  The ML volume level goes to 92 and the hum appears at 60. Previously when the earth was shared the hum was almost unbearable at 60 but now is significantly reduced. 
My question is that is the hum just part of the analogue experience or should it be absolutely quite? 
srafi
srafi OP
17 posts
 
Guys sorry did not mention I am not based in USA and laws are not the same and not as well enforced. How ever if this is a safety issue I could easily connect the new earth to the existing setup. 
My question remains. Is some level of hum part of an analogue setup or should it be absolutely quite?
Thanks for all the advice so far. 
jbny
37 posts
 
I don't think you should have any hum, on my analog inputs even with a tube preamp I have only a slight hiss at very high levels.
jea48
2,944 posts
 

I am assuming the OP’s "dedicated earth" is not connected to any other grounding system in his house. Though he really didn’t say how the ground is connected to his audio equipment. Is the ground connected to the equipment ground terminal on the duplex receptacle/s that feed his audio equipment? Did he disconnect the branch circuit equipment grounding conductor from the receptacle/s? Or did he leave the branch circuit equipment grounding conductor connected to the receptacle/s and connect his "dedicated earth" directly to the chassis of the audio equipment? If he defeated the branch circuit equipment grounding conductor and replaced it with his "dedicated earth" connection it is surprising to me he has not lost any equipment due to lightning. (Lightning would/will flash over from his "dedicated earth" over to the neutral, " The Grounded Conductor", in his audio equipment as well as travel through the in wall branch circuit neutral conductor back to the electrical panel service neutral to earth again.)

Also if the branch circuit equipment grounding conductor was defeated the OP has eliminated the low resistive path of the branch circuit equipment grounding to carry ground fault current back to the source in the event of a hot to chassis fault in his audio equipment. In the event of a fault the ground fault current path will be his "dedicated earth" connection. Works great for hunting fish warms. Sucks for providing a low resistive path back to the source, the grounded service entrance neutral conductor.

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Even if the OP connected his dedicated earth connection (?) to the branch circuit/s equipment grounding conductor, making it an "Auxiliary Grounding Electrode", I would not recommend it... Even if it would/does meet NEC Code 250.54 Auxiliary Grounding Electrodes. It would only add a path for lightning to enter his house and fry who knows what besides his audio equipment.

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Mother Earth does not possess some magical mystical power that sucks nasties from an audio system.

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jea48
2,944 posts
 
Guys sorry did not mention I am not based in USA and laws are not the same and not as well enforced.

Ground is ground world round.


 How ever if this is a safety issue I could easily connect the new earth to the existing setup.

Not sure what you mean. Please explain in detail. Per electrical safety code/s where you live it may be a violation to add a dedicated earth ground to your audio system, or to the grounding system of your electrical service of your home. I have read some parts of Europe the utility power company's transformer neutral conductor is connected to earth at the transformer only. An equipment grounding conductor is ran from the transformer/distribution box along with the power lines that feed the dwelling unit.  

My question remains. Is some level of hum part of an analogue setup or should it be absolutely quite?

Mine is dead quiet, and I do not have a dedicated earth ground.

For a test disconnect your "dedicated earth" connection from your audio system and then listen for the hum. Post back your results.

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srafi OP
17 posts
 
Here goes. I live in Pakistan and the earth supplied by our utility is useless. All houses have there own grounding sunk about 12-18 feet into the earth into a copper plate with bare copper wire coming out of the ground and providing earthing to the main distribution of the house from where this is run throughout the house. I have simply taken another connection point that is sunk further into the ground and which is not shared by the rest of the house. I do have a lightning rod connected to the main earthing system. What I have done may be harmful in some way that I am not aware of and would connect to the existing one.  
At the moment what I have done is takes the separate earth and connected it to the earth wire that is supplying the various resecptales that are being used in my set up. I have also taken another wire and connected it to a copper bus bar to which the analogue equipment is grounded through individual wires such as the earth wire attached to the RCA wire plug the earth plug at the bottom of the table as well as the earth on the phono stage. All the 3 pin sockets are also grounded in the sockets as they would be normally. 
This portion of the house is a new addition so it was easy enough to isolate the various wires to do this. 
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