PHONIC MM1202A
Manual de Usuario

UNBALANCED & BALANCED

UNBALANCED & BALANCED
Most of the mistakes in audio installations are due to incorrect and/or defective audio connections. In order to perfectly complete your installation, please pay special attention to the following section unless you are already familiar with balanced/unbalanced operations.

Because of the common mode interference immunity of a balanced system, the ground conductor does not need to carry any electrical current, which means the ground of the two connected units has an identical ground level which is vital to an interference free system. Let us look back at the unbalanced system. The signal electrical current goes from the signal conductor to the ground conductor. The ground level of the two connected units are not identical. This means the system is more easily inclined to noise interference. Running long cables is easy for a balanced system but difficult for an unbalanced one. A Lower noise level is a characteristic of a balanced system. Because a balanced system needs two conductors for the signal and one conductor for the ground, a

WHAT IS AN UNBALANCED LINE? You can find this kind of system in most of home audio-video systems. They have one conductor to carry signal, and another conductor for a ground. Normally, for lower level signals, the ground conductor shields the signal conductor.

WHAT IS A BALANCED LINE? A balanced system transmits signal via two conductors plus one ground shielding conductor. The two signal conductors carry the same signal but out of phase. For the balanced input stage, the amplifier will boost the difference between the two signal conductors and remove the identical part (known as common mode signal) of the two signals. Because the real signal is carried by the two conductors out of phase, so it is perfectly carried to the input. At the same time, interference that occurs during transmission will be identical (common mode). Because the signal conductors are run together, there is no chance they can be different, and all the interference will be removed by the balanced input amplifier.

minimum of three conductors are needed for wiring a balanced system. Therefore, a dedicated system separates the ground and shields the two conductors. Please read following section to properly wire for balanced and unbalanced systems:

THE CORRECT WIRING FOR BALANCED OPERATION Always connect the main power with three plugs. Make sure the power system ground is working properly. Do not use a ground insulator plug adapter without properly connecting the ground individually. This is vital to making a successful audio system connection. Always connect the ground pin (PIN 1 in XLR) to

THE DIFFERENCE BETWEEN TWO OPERATIONS

the source unit, and disconnect this pin on the destination unit. This connection topology is to avoid creating a grounding loop between the signal and power ground. Utilize only the power ground, be-

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MM1002a/1202a USER�S MANUAL

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