DAC/Amp Basics

Unbalanced RCA (Cinch):

Can be found on almost every consumer DAC or Amplifier. An unbalanced cable consists of two connectors with two conductors each, connected by two wires inside the cable—a signal wire and a ground wire. Inside the cable itself, the signal wire is typically in the center of the cable with the ground wire surrounding it. The ground wire serves two functions—it carries part of the audio signal and serves to shield the main signal wire to some degree from outside interference from noise such as the hum from lights and transformers, as well as RF (radio frequency) interference that comes from TV and radio transmissions. It does a decent job of rejecting noise, but unfortunately, the wire itself also acts like an antenna and picks up noise.

Balanced 3pin XLR:

A balanced cable, by contrast, has three conductors in the connector and three wires in the cable. Two signals wires plus a separate ground wire. As in the unbalanced cable, the ground wire still surrounds the signal wires and is used as a shield against interference. The signal wires both carry a copy of the signal, but the two copies are sent with their polarity reversed. If you sum two signals that are identical but are reversed in polarity, the signals cancel out, leaving you with silence.

The receiving gear will flip the inverted signal back into its original orientation. But because both copies of the signal picked up the same noise as they traveled along the cable—and that noise is identical on the two wires in the cable—flipping the polarity of what arrives at the receiving gear will produce the original signal intact and noise which now has reversed polarity.

Summing that gives you a welcome result: signal that’s preserved and noise that’s canceled.