Alright, I promised a overview on grounding our equipment. If you finish reading this, you will either have nothing better to do, or are very thirsty for arcane knowledge.
I first encountered grounding issues when I began building outdoor shortwave antennas several years ago. I had no idea how important the entire process of grounding played in all things electrical. There is a simple principal, however, quite ancient, that governs all things, and I feel obligated to explain it, in part, before I continue any farther in this discussion.
As a musician, rather one who toys with sound, I was granted the opportunity to experiment with a fundamental, universal manifestation known hereafter as the Law of Three. In effect, it dictates that all material and non-material things, in order to exist, must exhibit three definite properties: an active, passive and neutralising force. The neutralising force is normally unseen or ignored, but it is always present and vital. I will illustrate how the law works in one instance so that the reader may prove the existence of this anomaly to him or herself. If one takes any single tone of a definite pitch, such as that produced by a sine wave generator, a test tone CD or an electronic keyboard, this will represent the first force. Now, assuming most people can whistle the chosen note, begin to whistle the same note. This will represent the second force. Begin to slowly drop or raise the pitch of the whistled note. This will set up tension between the two notes. You will hear a third tone produced out of thin air which serves to relieve the tension between the first two tones. It will correspondingly raise or lower in opposition to the note which you are whistling, and it will almost seem as if the third note is manifesting in your head. This is what is known as the neutralising force. This Law of Three has been with us in all things since the dawn of time. Though beyond our range of hearing, it must then follow that the first note was, in reality, three separate vibrations within itself. And most of us, as instrumentalists, realise that any note on our instrument of choice exhibits harmonics. We may “chime” our guitar strings in three dominant places or over-blow our wind instruments in three steps. All three of these vibrations are within the fundamental note.
Electricity also, being a physical manifestation, works on the basis of the Law of Three using these qualities: Resistance, Inductance and Capacitance. Our recording equipment uses AC electricity and is thus at the mercy of all three manifestations. The third force is represented in our world by hum. And this hum (50 or 60 cycles, depending on where you live) which is produced by the pulling and pushing qualities of the AC current is the relieving of tension through the production of noise. If this noise is not “bled off”, it runs around in circles through our circuitry creating hum. I have truly over-simplified the entire process, but I am attempting to explain the practical use of grounding, in that we introduce it as our new neutralising force.
A grounded outlet has three (heh, heh) female receptacles or jacks. One is the active (seriously) or “hot” lead, the other is the passive or “common” lead and the third is our neutralising or “ground” lead. Depending on what part of the world you live in, you either have 117 volt current or 230 volts. If your home wiring doesn’t have the proper ground, hum will be impossible to get rid of and will be something that must be remedied. Any hardware store carries a nice and cheap little plug in circuit tester which will tell you if everything is wired properly by simply plugging it in and checking which LEDs light up. If the outlet isn’t grounded, or if it is the old two prong variety, it will need to be grounded or replaced. For those of you who understand the fundamentals of electricity, grounding an outlet will be something that you will probably be able to take care of yourself. For those with no electrical know-how, there is only one fundamental: Electricity can kill you. Therein lies my disclaimer if anyone gets broiled. I might also add that there are over 15 different types of electrical connectors throughout the world. Many in Europe, Asia, Africa, Argentina and Australia are the older two prong varieties. For some of you, it may be a simpler task to simply ground the central piece of equipment and forgo the grounded outlet option. After the ground is established, it is merely a matter of running a grounding wire from a screw of the equipment chassis to the ground.
For those of you in the former group, all you have to do is switch off the power at the main breaker. A plug-in circuit tester will let you know when you have found the proper breaker or fuse. If you are not able to absolutely ascertain which breaker or fuse feeds the circuit, turn off the power to the whole structure. Better safe than sorry, for sure. Next, remove the wall plate surrounding the outlet and remove the screws which secure the outlet to the box. You will have to replace this older two prong outlet with a three prong type. Or, your outlet may already the three prong variety but you’ve discovered that you have a floating ground. You will need to prepare a ground in either instance.
The best ground is an iron or copper cold water pipe. If there is no water supply line within relative close proximity to your outlet, the next best thing is a six foot copper grounding rod which must be pounded into the ground. This brings up all sorts of issues, usually. An insulated stranded copper wire of 8 or 10 gauge makes an excellent ground wire, and the shorter the wire, the better. Since a ground wire is not shielded, it is capable of picking up extraneous noise (much like an antenna) and can actually become another source of noise, so it is easy to see the importance of this matter. If a ground rod must be installed, it will obviously have to be installed outdoors. The rod is simply (or not so simply) hammered into the earth until only fifteen centimetres or so remain above ground. A clamp must then be installed that one end of the ground wire is secured to. The wire must then be run as directly as possible to the outlet where the other end is secured to the ground screw of the outlet. This is usually located on the body of the outlet, separate from the power connection screws. It is sometimes a green colored screw or is otherwise notated on the outlet body. The power wires must be connected correctly as well to their respective terminals and then the whole thing can be re-installed into the box. After everything is together, re-energise the outlet and plug the circuit tester in to make certain that everything is copasetic. Now all you’ll need to do is plug a power strip* into this outlet and there will be enough ground to go around. And one big noise headache will be eliminated!
If your studio is not on a ground floor, you are already up against a major problem and there are no quick fixes. If you cannot drill a small hole into the corner of the floor to access a cold water pipe or if the logistics begin to look harrowing in any case, again I suggest that you call an electrician.
* Power strips come with breakers, noise filters and other options. These are extremely useful when running computer equipment as well. If you have rack mounted equipment, I strongly suggest a power conditioner such as those manufactured by Furman. These devices will save your equipment from voltage spikes or anything else short of a direct lightning hit and are well worth the investment. During thunderstorms, I immediately unplug all of my equipment!
Johnny Nowhere is not a licensed or qualified electrician. That didn’t interfere with his learning, firsthand, how to do all of this work, nonetheless.