Acceptable Level Ground/Earth Noise
I have a dedicated earth for my audio system ... 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...If this ground isn't connected to your house ground, that's a violation of the NEC and potentially hazardous. Avid makes a phono stage called the Phallus? That's just plain weird. |
Dedicated earth ground? As not connected to the main grounding system of the electrical service of your house? If that is the case you have two earth connections that are not electrically connected together and therefore are not of equal ground potential. Not only is it dangerous it can cause 60 Hz hum. // "From Henry W. Ott’s big new book "Electromagnetic Compatibility Engineering" |
@cleeds is absolutely right. You cannot just arbitrarily make a new ground. It's in violation of local and national codes, dangerous and wont' really get you much. It must be appropriately bonded to the house ground, which must be bonded to the neutral at the service entrance. From that point however you may run as many grounds as you'd like. |
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. |
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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. |
I have tried to disconnect the earth to worse results. The reason I have put in this separate earth is so that the audio equipment would be isolated from the rest of the house. It gets pretty hot here so we pretty much use AC year round and the load in the house is pretty high. I did forget to mention it gets louder when I touch the tone arm so could be something else. Genuinely looking for help not trying to invent a new system or any thing. I may have done things wrong and any help would be appreciated I wish I could post pics to give a better idea. |
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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....What I would suggest trying, if you already haven’t, is disconnecting everything in the system from the copper bus bar, and connecting the earth terminal on the bottom of the turntable directly to the earth terminal on the phono stage. With that connection between the turntable ground and the phono stage ground being as short and direct as possible, and in particular not routed anywhere near your power amplifiers. Also, if the power supply of what I presume is the Avid Pulsus phono stage (I’m guessing that your auto-correct software changed "Pulsus" to "Phallus") is located right next to the phono stage unit itself try moving them a foot or two apart. And make sure that all power cords are separated from the cable carrying the phono signals by at least several inches, and preferably more. If a power cord and the phono cable must cross at some point, have them cross at right angles. If those things don’t resolve the problem, as an experiment try putting a cheater plug (a three-prong to two-prong adapter) on the AC power plug of the phono stage's power supply, to temporarily defeat its safety ground connection. Let us know the results if you do that. Jim (Jea48), thanks for posting the Henry Ott writeup. I’ve seen that before and I always get a chuckle out of it, especially no. 8. For others who may not be aware, Mr. Ott is one of the world’s leading authorities on grounding and various other aspects of electronic design that often tend to be mysterious even to trained EEs. Regards, -- Al |
Connect that ground to where the house ground and lightning ground are connected thereby creating a star ground. This way the voltages across the ground rods will be the same in the event of a lightning strike. As a bonus, the (somewhat) equal voltages will deter stray currents into the neutral and lower that hum even more. |
Srafi, you should follow local laws. If they are not enforced, you still should bond any ground to your service ground. Otherwise you defeat the purpose. As for humming, start a new topic, but depends on your equipment, and if you have DC on the line. DC can be caused by dimmer switches. Here, the usual source of hum and ground loops is external TV like Cable or an antenna, and PC's. In both cases the best solution is a ground loop isolator. Best, Erik |
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@srafi Your utility pole does not provide a ground, it provides a neutral. It’s up to the service entrance to provide a suitable ground. You MUST bond ALL grounds together, and bond that to the neutral coming off the pole. Having said that, you may use as many ground rods as you’d like. :) What you cannot do is arbitrarily use one rod for one room and another for the rest. The reason for this is that is prevents the safety ground from working correctly. If a short develops to a case, and this independent ground rod is 10 feet from the house ground rod it can be many volts different than your neutral now. 10s to hundreds. It’s worse with dry soil. The safety ground should guarantee that the case of your electronics is 0 volts, but if it's at some other, random point, it could be quite higher than 0. That's where you loose your life. :) |
Hi Al, I think Ott hit the nail on the head with #4.
AL, I agree with your post above about disconnecting all that earth grounding that srafi has added, connected, to his audio system. It does nothing for the SQ of his audio. If anything it adds noise. The only ground he should have connected to his audio system is the safety equipment ground.
To me that sounds like the tone arm is not grounded to the signal ground of the phono preamp. LOL, I’m almost hesitant to use the word grounded. Some take the word as meaning mother earth ground. If the TT has a ground wire and srafi has it connected to the chassis of the phono preamp it could be the ground wire connection is open/broken. If that is the case there is a good chance it would be inside the TT. For a simple test he could connect a wire at the phono preamp chassis and then touch the other end of the wire to the tone arm or to the tone arm support tower. If the hum stops he has found his hum/buzz problem. I would also check the cartridge phono wires to make the connections are good. Jim . |
@srafi, I was searching for some information on your turntable. I ran across the owner manual and found this note.
It doesn't say were to connect the other end of the cable/wire. I would think it should connect to the phono preamp chassis ground lug/terminal. Do you have this ground wire connected to the turntable? If so where do you have the other end connected? Another question. What is the arm you are using on the table? What material is it made of? Clearaudio Performance DC Turntable owners manual. http://clearaudio.de/_assets/_pdf/manuals/turntables/CA_Performance%20DC_E.pdf . |
I did forget to mention it gets louder when I touch the tone arm so could be something else.Most definitely! The tone arm tube should have continuity to the chassis of your phono preamp. If it does not, hum is a likely result. Is some level of hum part of an analogue setup or should it be absolutely quite?Hum is not part of the analog experience. You might get hiss but hum is an indication of a problem somewhere. |
