JBL P R X 5 1 8 S Stereo Amplifier User Manual

Balanced vs. Unbalanced Lines
Your PRX500 series can accept either type of input. There are two basic types of audio system interconnections
for audio signals: Balanced and Unbalanced.
Balanced Lines
In audio, a balanced line is a three-conductor system in which the two signal wires carry an equal, but opposite
voltage with respect to the ground wire. The ground wire acts only as a shield and does not carry any audio
signal current. Outside interference (such as RFI - Radio Frequency Interference) is either shielded from the
internal signal conductor, or if it gets into the cable is cancelled out by the opposite signals at the receiving
end. Balanced connections are preferred for any longer cable runs.
Unbalanced Lines
Unbalanced cable is a two-wire system where the shield (ground wire) acts as one of the current carrying signal
conductors. The center conductor enclosed by the shield is commonly known as the “hot” conductor. Unbalanced
audio cables do not reject noise as well as balanced lines. Unbalanced lines are typical in home hi-fi type
systems and on the outputs of electronic musical instruments. These work well if the distance between the
components is short, the signal level is relatively high and all of the electronics used in the system are plugged
into the same AC service.