Tech Tip:Electrical Power And Distribution

Editorial note: This week's tech tip features Casey Zygmont of Furman Sound, Inc., addressing issues of electrical power and distribution, and how Furman products can help.

How's your AC power? Before you plug that new piece of equipment straight into the wall or straight into a cheap power strip, ask yourself these questions: What is the quality of your AC power? How does it impact the overall performance of your equipment? There are several factors to consider.

AC Line Noise And What It Means To You And Your System
Wherever you're located in the United States (or the world for that matter), the quality of the AC power delivered by your local power utility is far from ideal for today's sensitive audio equipment, computers, and digital components. AC line noise invariably ends up in the audio path and adds to the noise floor on your audio signal and has a noticeably negative effect on the quality of your audio or video.

Over the last 10 years the amount of AC line noise has increased 100-fold and promises to become worse! On top of this there has also been an increase in the overall bandwidth of this noise, spreading it further across the audible audio spectrum.

Today's power grid, as proven by the recent massive failures in the eastern U.S., is overtaxed and obsolete. This means what you're getting, no matter where you live, is contaminated, dirty, noisy AC power.

In fact, typical AC power coming directly from the wall can add as much as 24dB or more to your audio noise floor (remember your ear can notice changes in volume in increments as low as 3dB). This represents a significant and very audible increase of noise added to your audio. This noise impacts the clarity, resolution, and performance of your audio components and the audio they reproduce.

Voltage And How Fluctuations In Voltage Affect Equipment Performance
Is your electrical service delivering a constant, clean, stable 120 volts? In the vast majority of cases the answer is no. Voltage swings and fluctuations are extremely commonplace. Demands on the local power grid and individual service in buildings cause significant variances in voltage. At 9:00 AM the voltage may be fine, but check it at 2:00 in the afternoon when every building in your grid is up and running. You'll find it's probably considerably less than the standard 120 volts. At the nightclub where you're playing, it may be fine when you're doing your sound check at 4:00 PM but what is the situation when the club is in full swing with all those power amps and instruments pulling AC off the same electrical service? Have you ever noticed the lights dim or flicker when a certain appliance kicks in? There are many things that commonly happen to affect AC line voltage and none of them are good.

Both under and over voltage delivered to your equipment has a noticeable impact on the audio performance of your system. For example, if you compare the sound of a typical vacuum tube guitar amp receiving 110 volts versus one receiving a full 120 volts, you would be astounded by the difference in the sound.

Specific electrical components perform far below par when not fed the specified full 120 volts. Amplifiers deliver a fraction of their potential power to the speakers when they do not receive sufficient voltage. Computers can lose data and experience myriad other problems.

Furthermore, the lifespan of specific components such as switching power supplies are compromised when fed insufficient voltage. If you value your equipment, feed it a steady diet of clean conditioned, regulated AC power.

Furman makes a full line of voltage regulators designed to deliver clean constant voltage at varying amperage (15, 20 and 30 amp versions are available). And, as in all Furman products, your AC power is also filtered to reduce AC line noise as well as protected by Furman's proven electrical surge and spike protection.

Electrical Surges And Spikes
Whether you know it or not, your equipment is subject to hundreds of electrical surges and spikes every day. Some originate from your power company. Others are caused by nearby appliances or just the power demand on the local power grid or individual electrical service. While the vast majority of them go completely unnoticed, they do have a long-term impact, shortening the lifespan of components inside your equipment. It may take a year or two to experience this effect (after your product warranty has ended) but these failures are not in the least uncommon.

There is always the chance of experiencing a very large surge or spike that can be devastating and destroy your equipment. Furman techs have heard countless stories from our customers about how the effects of devastating events (such as a lightning strike or power outages like those that just happened on the East Coast) were avoided by using Furman Power Conditioners.

When this kind of catastrophic event occurs, you want that power conditioner to sacrifice its protection circuitry. Typically, MOVs (Metal Oxide Varistor - this is the component designed to burn up instead of your equipment) are the components sacrificed within the power conditioner and are replaceable at very low cost. Compare this to the cost of replacing all your equipment.

What can be done to reduce or eliminate AC line noise from your system?

Furman AC Power Conditioners
Even using a simple, low-cost power conditioner will improve your audio quality by lowering AC line noise. It's important to note that AC power conditioners are not all equal. The level and amount of noise filtering can vary significantly. The type of filters used as well as the bandwidth of these filters has a big impact on the amount of noise filtered out. All Furman Power Conditioners are optimized for reducing AC line noise across the audible audio spectrum (20Hz-20kHz). The amount of surge and spike protection also can vary. For example, many simple power strips claiming this protection offer only a single MOV. This is far from sufficient to protect your equipment from a substantial surge or spike.

Balanced Power
Balanced power represents the absolute cleanest, noise-free AC power available today. This circuit works in a manner similar to a balanced audio signal employed to eliminate noise. Two lines of opposite polarity eliminate virtually all noise present on the AC line.

If you care about feeding your equipment the cleanest possible AC power, balanced power is the way to go. And whether you're a full-blown recording studio, DAW owner, or mobile DJ with a rack full of high-powered amplifiers, Furman Sound has the perfect balanced power unit for your application.

Voltage Regulators
As their name implies, they regulate voltage and ensure a constant clean 120 volts at all times. These units actually compensate for voltage fluctuations by stepping up or stepping down the AC line voltage.

Furthermore, as with all Furman AC products, your AC is filtered, significantly reducing the noise referred to earlier. All Furman's products also offer Furman's proven surge and spike protection to safeguard your investment and equipment.

Furman offers a complete line of 120-volt AC line regulators, available in 15-, 20-, and 30-amp versions for whatever your application demands.

Planning on a world tour? Check out the Furman AR-PRO. It will deliver a clean constant 120 volts from any power source anywhere in the world.

Power Conditioners
Single-rackspace power conditioners perform two primary functions. First, they reduce much of the AC line noise by filtering it out before it reaches the audio signal. Second, electrical surge protectors are designed to protect and, in extreme cases, sacrifice themselves instead of your more valuable components.

Furman Sound has a complete line of AC power conditioners (model numbers include all products beginning with PL or PM). There are several models to choose from in both 15- and 20-amp versions to suit virtually any application.

Whatever your A/C power management needs, Furman Sound has the solution.

Casey Zygmont
Furman Sound, Inc.