Hello folks! Welcome back to The Corner. This week we’re going to discuss a source of noise that not everyone is aware of, dirty power. Dirty power basically refers to line noise coming from older wiring and improperly wired AC circuits found in older homes and some small venues. Dirty power can cause major noise issues and can drive a lot of people insane troubleshooting their rig when the problem is actually not in their rig at all!
So what is line noise? To put it as simply as possible, line noise is random fluctuations and electrical impulses carried along with the standard AC current. This can be caused by fluorescent lights, large appliances, nearby large transmitters (radio stations), and older AC circuits that haven’t been updated to current electrical standards. Line noise can translate directly from the wall into your guitar rig causing many people to pull their hair out trying to find the source of the noise. Unfortunately, there are limited options but there are a few things you can do to be prepared for any sort of noisy power.
Knowledge is Power
The first step in fighting this annoying source of noise is knowledge. First, have a basic understanding of a ground loop, what it is and how to avoid one. When you set up your gear, make sure your rig is ground loop free. This may not protect you from ground loops elsewhere like at a club but it will at least make sure your rig is set up properly to avoid any troubleshooting in that area.
Second, know what else is on the circuit. If you’re at home, check the breaker box for the plug you use and see what else is hooked up to it. If you kill the breaker that you plug your amp into and the refrigerator turns off, then you should probably use a different outlet for your guitar. Appliances, water heaters, fluorescent lights, fish tanks, and even some HDTVs can induce noise in the line. Make sure your audio equipment uses a plug that only shares power in that room, this way you know exactly what else is on when you play.
Since it’s not possible to control which circuit you’re on when you’re gigging, the next step is to be prepared. I’ve played countless clubs that shared stage power with the lighting. The worst is dimmer switches; they seem to induce more and more noise as the lights are dimmed. There are a few things you can do when gigging that will minimize the effects of line noise.
First, know your venue. Most places that have live music night after night will have the stage power isolated from the lighting rigs. This may not always guarantee a complete lack of noise in the lines but it will drastically reduce the likelihood of getting dirty power. If you’re playing at a venue for the first time, ask them about the power. If the booker/owner can’t tell you, ask the sound man. Show up early and ask about lighting and power and have them show you where you’re going to plug in. Let them know that if they have any lights on a dimmer, you would prefer they do not use them during your set. Most venues will accommodate the artist as long as your requests are reasonable.
Second, have a power conditioner. I cannot stress this enough, please spend the money on a nice power conditioner that has line filtering and surge protection. Not only will the unit protect your gear in case of a surge or brownout but most of these units have built in filtering that removes or reduces line noise. The specifications will list a dB rating at a specific frequency. The higher the dB rating the more filtering that is available and the quieter the unit will be.
What to Use
When looking for a unit to reduce line noise, you want to consider your situation. Obviously you don’t want to spend hundreds of dollars on a line conditioner with 8 outlets if you only plug in your amp and pedal board power supply. Also, if you never play out and only play at home, one of these units may not be the best investment. In this case, check out a unit like the Ebtech Hum X or the Audio Prism Quietline. These are individual units that filter one plug at a time and are perfect for home and studio use. They do work for gigs as well but if you’re a gigging electric guitarist then you likely have a band and for a band there is a better solution in my opinion.
The band situation is where you will want to consider a more expensive power solution. In this case that eight outlet power conditioner that costs several hundred dollars might be the way to go. Think about it this way, that one unit can protect not only you but your other guitarist and bass player from noise and power damage as well. Instead of hauling around a few small Ebtech units (which do not protect against power surges) you might as well have one master unit for the entire band’s gear. This way you only need one outlet on the stage and the larger cost of the unit can be defrayed by each band member pitching in. Make sure the unit is rated for the power you require and that the gear you’re plugging in isn’t going to draw excessive amounts of current and this solution will work just fine. It also prevents ground loops in your stage setup. Companies like Furman, Tripp-Lite, and Monster make high quality, filtered power conditioners that will eliminate noise and stabilize incoming line voltage.
The one thing you do not want to do when faced with noise is use a ground lift. Those little “three-to-two” prong doodads that the kid at Radio Shack is always quick to suggest are a bad idea. They can lead to injury or death and that goes for your gear as well so just don’t do it.
Well there we go folks. Unfortunately, unless you’re a qualified electrician there’s not much you can do to eliminate dirty power but there are steps you can take to be prepared to fend it off and protect your gear. A small investment can save a lifetime worth of frustration, especially when you’re on the road or on your own dime. Thanks for reading folks. We’ll see you next time, in The Corner.