Audio Power Industries Table of Contents


Making Your Selection

The Ultra Series
The Ultra Series

Power Wedge® 1118
Power Wedge® 1118

Power Pack Power Conditioners

Power Link Power Cords


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Making your selection
The Ultra Series
Power Wedge® 1118
Power Pack Power Conditioners
Power Link Power Cords
FAQ
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Ground hum
A 60 Hertz hum audible through the speakers is most often the result of a ground loop somewhere in the system. If a system has a ground loop, adding a Power Wedge Ultra will not necessarily eliminate it. Unlike some power conditioners, Audio Power products do not float the ground.

The Ultra Wedges have a unique AC ground reference configuration switch for each isolated outlet. The best AC reference for each individual component can be selected using this switch. The optimal position in most cases is the "Reference" position which delivers perfectly balanced AC to the component. There are some components that anticipate the neutral being directly ground referenced, and the "Normal" position of the switch will provide that configuration. In other cases, the "Float" position may work best, providing no direct reference for the AC allowing it to float, similar to the output of the older Power Wedges. It is important to note that the safety ground is always present on the third pin ground of each outlet. The switch only controls the AC reference for the hot and neutral legs. Sometimes, simply moving a switch to an alternate position can eliminate a ground loop hum.

In some cases adding an Ultra Wedge will seem to create a ground loop. This can occur for several reasons. In some cases, components have been plugged into a wall outlet or power strip in ways that did not establish proper electrical grounds for them. Plugging them into an Ultra Wedge allows them to achieve a ground which can cause an interaction between components. The Ultra Wedge is not causing the ground loop. In all cases the Ultra Wedge passes on the ground present at the wall outlet.

Another possibility is the separate ground that is provided by an incoming cable television line. When a television is combine with an audio system to form a home theater system there are often two different ground potentials: the AC power ground and the cable ground. If this is a problem, there are a number of products available that will eliminate the ground hum by isolating the cable ground.

In some cases, the only way to resolve a grounding problem will be to float the ground on one or more pieces of equipment. Since many components require a ground for proper operation we strongly encourage you to contact the manufacture of the equipment before you float the equipment ground. In some cases, using equipment without a proper ground will void the manufacturer's warranty.



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