DT, you are not quite clear to me: Generally a dedicated line starts from the grid of your home directly to your listening area and is used for nothing else, but your gear. It also has separate fuses, best those old fashioned ones, which need replacement, once they have blown. These lines take their ground generally from the grid and in many countries the electrician is bound by regulations and law how to do this.
If I were in your shoes, I would start with this setup, plug in the gear according to the manufacturer's instructions ( generally grounded ) and just listen. If there is hum, you have a ground loop somewhere. To combat this, you have to experiment. Sometimes you have to remove the grounding from a specific piece of equipment ( but careful, sometimes the manufacturer insists, that the unit be grounded ), sometimes you have to run a piece of grounding wire, say between a recordplayer and your preamp. There are no fast and ready rules, its a matter of trial and error. Sometimes you have to use a cheater plug, to reverse neutral and hot. If you are not familiar with tweaking powerlines and plugs, I would let a knowledgeable person do this. (Shock and fire hazard, brown outs )
Star grounding means, I think, that you ground one appliance in your system, generally the preamp/linestage, let the rest of the system "float", which means that your remove their individual grounding by say cheater plugs and in a last step, connect that equipment via grounding wires to your preamp, which you did not float. In other words, all of your gear is grounded at just one point. In theory this is easy, the practice is difficult, the benefits not always as expected. Besides, if you have a dedicated line and you plug in your gear just in there, there is a common ground to all of them anyway.
I am not a technical person, I'm talking out of experience so please wait for more knowledgeable posts on this topic. When I ran my dedicated lines, I took the grounding from the main grid and listened happily ever after.
Good luck DT!
What you could discuss with your electrician is the quality of your existing ground. He will know, that there are different ways of gounding withing the existing regulations:
Grounding from the grid, grounding to the heating (risky, because these days plumbing is only partly metal, often plastic and hence useless, grounding in running a dedicated copper rod deep into the earth. Sonic differences are slight if at all, using the normal gound from the grid is probably your best bet. |
I ran a dedicated line to the audioroom and separated it into 4 circuits. I ran a 220V and stepped it down with a toroidal transformer. If you are going to run a dedicated line--I recommend this. It gives you two live wires out of phase (both at 55v). As for the ground I used a dedicated true earth ground nearest the subpanel (located adjacent to the audioroom). There was the concern of hum with different grounds, but I was fortunate and didn't have that problem. Definitely one of the most cost effective upgrades I have ever done. |
If you tell a qualified electrician to run a "DEDICATED" circuit with "ISOLATED" ground to each receptacle, what you will have is the following: A separate Hot, neutral, and ground wire from the receptacle back to your panel. The ground wires will be electrically isolated from any other ground or neutral wires in your system.
To be "DEDICATED" each receptacle would be on a separate circuit breaker (or fuse). Normally, the neutral and ground would be landed on the same neutral bar in your panel, and from there a main ground conductor would run to your main house grounding point. Usually a ground rod driven into undisturbed earth).
To be truly "ISOLATED", a separate grounding bar which is electrically isolated from the electric panel enclosure is installed in the electric panel. The main ground wire from your main grounding electrode (rod) would be attached to this bar, and all the circuit ground wires would be attached to this "ISOLATED ground bar" If your system is old, this may be difficult thing to do.
However, a separate ground (not isolated) from each receptacle back to the panel will likely suffice for your needs. Occasionally, the separate grounds are taken all the way back to the main grounding point, but if this is not done correctly, and a ground wire becomes loose and somehow creates another path to ground, the results could be dangerous. This is also true of any gound conductor, anywhere in the system.
Bottom line: If you consult with a qualified electrician, and tell him exactly what you are wanting, he/she should be able to provide a code approved installation.
Hope this helps. |
Addendum to my previous post, please note: It is necessary that ALL ground wires are ultimately grounded at one, and only one, main grounding electrode. Due to the difference in electrical potiential of the two grounding points, failure to do this could result in damaged equipment, or even electrocution. This is a code required life safety issue! |
Hi, I just installed a dedicated power supply. From main breaker box from a 50 amp breaker I ran 6 awg romex to sub main box.Sub main box (8 breaker type) I used 4 20 amp breaker that were connected to same phase at this box which is important for best results.I ran seperate ground wire to sub main box to 10 foot ground rod (make sure electrician installs this seperate ground rod & doesn't tie into existing ground rod because this really lowers the noise.Note the 6 awg 3 wire romex between main & sub box the ground wire is connected from sub box to main box & seperate ground to outside rod is connected to sub box.I then installed 4 seperate dual gang (2 outlet) outlets. This made a big difference with quieter background, better bass and no annoying pops when ac unit or refrigerator cycles.Also I have great results using a Chang Lightspeed CLS 9600 ISO power conditioner everthing except amp is plugged direct to outlet for best results. Hope this helps it worked great for my ststem. |
Although I agree that a separate ground wire and grounding rod to the sub-main box MAY lower noise, electrical code strictly prohibits this for the aforementioned safety reasons. You won't pass inspection if you do this. It doesn't sound like the original poster has the understanding to do some post-inspection reworking. Stay within code and just have the electrician upgrade your current main ground. |
Thanks Metaphysics, for helping me make that point again. It seems some (well meaning no doubt) audiophiles just do not have a good understanding of the dangers involved with multiple grounding points. And as you've stated (and I as well), it is against National Electrical Code to do so.
DIYer's beware, your quest for better sound could cost you more than a few bucks. BTW, for reference, I am a licensed electrician and commercial contractor.
I just don't want to see anyone fry their gear, or themselves! |
I'm using a single 20 amp circuit that uses an isolated ground outlet (ugly orange) and 12-3 BX back to main panel. Grounded to main buss bar. Got great (no noise) results and pretty cost effective. Red wire wrapped in green tape to designate ground. Maybe Gbeard can comment as to whether BX or conduit is over kill compared to romex (will certainly increase cost) and add a simple definition of "Star Ground".
Some schools of thought recommend monoblock amps be connected on opposite sides of main (common noise cancellation). General consensus in non-monoblock situations is to keep all lines on same side of main. May also be some benefit to locating potentially noisy house lines (those with motors, dimmers, computers, etc) on the opposite side of the main. My computer for example has it's own 15A (14-3)iso grd circuit on opposite mains side.
If you still have noise issues after a code compliant install look for the source by switching off suspect items. Deal with not generating the noise rather than floating the ground and risk floating to heaven. |
I don't really think that BX, AC, MC cables, or conduit are probably any better than romex of reasonable gauge wire. #12 or #10 should be sufficient for most applications. Especially since the terminals for a 20 amp duplex receptacle are not designed to accept a conductor larger than #10. However, when entering the galaxy of the audiophile, anything is possible--as long as it is safe.
I don't really understand your comments about circuits being placed ahead of the "main". It must be a different definition of the word than what is common in the electrical industry. Nothing should be tapped ahead of the main circuit breaker (or fuse), unless it has its own main circ. breaker (or fuse) within the code approved distance per the tap rule. I am sure I am not discussing the same situation you are refering to.
I am not an expert on star grounding, but I believe it is a method of grounding electronic systems--audio, video, computers, etc.--that begins at one point in the system, and branches out to each piece of equipment in a star configuration. It can be very technical, and I am not well versed in its design criteria. However, I do know that the grounding point at where the "star" begins is itself grounded to the main grounding electrode (or mat in larger systems).
I hope this helps. |
Alexander,
After re-reading your post, I think I totally misunderstood.
You must be refering to balancing the load by placing mono-blocks on opposite phases (A or B) of a 120/240volt system.
I don't really know about an improvement in sound--I've never owned mono-blocks! ;?) |
The ground point for my house is a clamp around the copper water pipe that enters the house. I found that paint had covered the pipe. I removed the clamp and sanded the pipe down to the copper and sanded the paint off the ground cable. With regard to separate lines, I have two lines that share the same ground but if I use both outlets there still seems to exist a difference in ground potential. Hum is least when everything is connected to only one circuit. |
I would recommend hiring an electrician to handle this type of work, lest you become a famous conducter. |
Hi,
Thanks for all your helps. I'll call an electrician next week and print all the posts to him to see what he suggets.
Thanks again
DT |
My best advise, Hire a Licensed Electrical Contractor and make use He or She pulls a permit for the Job from your local Building Dept. This will cover your ass with your insurance company if some jerk burns down your house. |
