Balanced Cable Line Out

In balanced signal paths there is a second signal conductor referred to as the cold line.

Balanced cable line out.

For an unamplified telephone line a twisted pair cable could only manage a maximum distance of 30 km. The signal wires pass an identical audio signal through each wire while the surrounding ground wire works the same as in unbalanced cables shielding the signal wires from external electronic interference. As in the unbalanced cable the ground wire still surrounds the signal wires and is used as a shield against interference. Two signals wires plus a separate ground wire.

A balanced cable by contrast has three conductors in the connector and three wires in the cable. As the signal voltage in the hot line increases the cold line s signal voltage decreases precisely mirroring the hot signal in reverse. But what makes a balanced cable special is the way the gear utilizes that. The cable construction used for balanced telephone cables was twisted pair.

Balanced cables have three wires inside the plastic casing. However this did not become widespread until repeater amplifiers became available. The hot and cold lines transmit identical signals that are 180 degrees out of phase with each other. In both cases one jack is normally used for each audio channel left and right.

Unbalanced line level connections are usually implemented with rca jacks for audio while balanced line level connections typically utilize dual 3 pin xlr jacks for both the input and output. However if you re out to save money then unbalanced cables might be your best choice especially if you re just using really short ones.