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Heat Buildup and Your AV Components

by Bo Dragsdahl April 14, 2007
Heat Buildup in Components

Heat Buildup in Components

If you want to ensure that your expensive electronic components enjoy a long and full product life cycle, you must make sure to keep them operating at a comfortable, cool temperature. The number one factor that kills electronic components is overheating. Even short of an outright meltdown, excessive heat causes electronic components to function less reliably and reduces their overall life span.

Stay below 85 Degrees F

To achieve optimum performance and optimum equipment life, it is recommended that you keep your system operating at a standard temperature below 85 degrees F. Most studies show that every 10 degree increase over 85 degrees F leads to a whopping 40% reduction in your equipment’s life span.

Computer microprocessors are more sensitive to heat than traditional A/V equipment. All microprocessors have a maximum allowable temperature, beyond which they burn out. With the increasing use of microprocessors in A/V components, sound system owners nowadays have to contend with the same heat sensitivity problems that computer owners have for decades.

Where does the heat come from?

Ironically, the heat that threatens to kill your components is produced by the components themselves. As you use your entertainment system to watch movies or play music, most of the components convert much of the power they consume into heat. The more high-powered your components, the more heat they generate.

The possible exception is your amplifier. The heat output of amplifiers depends on a range of factors relating to their design and use. Traditionally, amplifiers have always been the great heat producers in any sound system. But microprocessors, which are becoming integral to most components, are not only the most sensitive to heat; they are also great heat producers themselves. The faster they are, the more power they consume and the more heat they produce. This means that amplifiers are being joined by more and more components that generate large amounts of heat.

Heat building factors

How fast heat builds up in your sound system, and how high temperatures it will reach, depends on a variety of interrelated factors.

  • The wattage of your electronics. The amount of power your system consumes directly determines how much heat it generates.
  • The size of the cabinet that houses your system.
  • The amount of airflow and air turbulence in the cabinet.
  • The density of electronics in the cabinet (i.e., how much free air is left between components and shelves)

Airflow is the key

As long as the heat can dissipate, your equipment is safe. Heat buildup has never been a problem with the traditional open stereo rack. However, audio/video cabinet enclosures, such as StudioTech’s Ultra cabinets, are becoming increasingly popular. The risk of placing equipment in an enclosure is that hot air may get trapped if it cannot escape fast enough, which will result in a continuous increase in temperature.

The key element to keeping your components cool in a cabinet-based system is airflow. A steady inbound flow of cool air and outbound flow of warm air is the key to keeping component temperature down.

Relying on Natural Airflow: Passive Ventilation

Overheating is prevented when there is sufficient cool air flowing through the cabinet to carry away any excessive heat.

In the absence of any air motion, hot air will build up in a pocket around each heat producing component in a cabinet. If this is allowed to happen, the temperature will keep rising until the system has fried itself. What prevents overheating is movement in the air. More specifically, it is the movement that allows cool air to flow in and replace the warm air.

When a stream of cooler air meets a pocket of warmer air, the warm air is caused to rise toward the top of the cabinet. A steady flow of cool air into a hot component system thus creates an ongoing, upward stream of warm air. This process is called convection.

Passive ventilation

Natural convection, as the name indicates, is the process of air replacement that takes place due to natural turbulence in the air. If your component cabinet has sufficient openings for cool air to flow in and hot air to escape, then your components will be cooled to some extent just due to the fact that the air is set in motion by any movement in the room. Whenever the air is stirred up, cool air will make its way into the cabinet and cause a flow of hot air out of the cabinet. This process is also known as “passive ventilation” – “passive,” because it takes place without any effort to facilitate it.

StudioTech’s Ultra cabinets are designed to facilitate such a process of passive ventilation. The mesh screen door, side vents, and generous rear openings jointly make possible a substantial flow of air right through the cabinet.

Creating an effective airflow

To achieve the most effective passive ventilation you must try to create a “chimney effect” by leaving an unobstructed vertical column of air where hot air can freely rise and escape. Ultra U-48 and U-60 cabinets are designed to create such an effect. Rather than reaching all the way to the sides or rear of the cabinet, the shelves inside are situated in the space between four corner pillars. This design leaves narrow “chimneys” on both sides and at the rear. However, the relatively narrow design of the cabinets places some limitation on the effect.

To ensure that heat can freely escape each component, leave some space between shelves. If you pack the interior of the cabinet densely, airflow is restricted and pockets of hot air will more easily form around your components.

The upward motion of warm air is created by the temperature differences (called “gradients”) between cool and warm air. To create the most effective airflow, you should strive to place the hotter components at the top of the cabinet. This way you create the greatest temperature contrast, and keep the warmest air closest to the exit.

Also make sure to keep the surrounding room temperature down. In order for cool air to flow into the cabinet, there must be cool air in the surroundings. And in order for hot air to rise out of the cabinet and escape, the outside surroundings must be cooler than the escaping air. To maintain the maximum operating temperature of your components at 85 degrees F it is recommended that you keep the air in the surrounding room at 75 degrees F.

Special thanks to StudioTech for this information. To read the rest of this article please visit StudioTech.com.