Analog interconnect
Overview
The term "Analog interconnect" is used to describe an electrical cable used to connect audio equipment. This can include coaxial cables with RCA connectors, shielded twisted-pair cable with XLR connectors, twisted-pair or coaxial cables with 1/4" "phone" connectors, and an adapter cable with different connectors on each end.
Basics
Analog interconnects basically fall into two sub-categories:
- Balanced
- Unbalanced
For more information see Balanced and Unbalanced
Balanced interconnects
Balanced interconnects typically take the form of shielded twisted-pair cable with XLR or 1/4" T.R.S. connectors on one or both ends. Most cables have the same type of connector on both ends; but an Adapter cable can be used to make a balanced connection between equipment that has an XLR connector and equipment that has a T.R.S. connector. Cables of this type typically carry +4dBu professional level signals or low level microphone signals. The twisted-pair of conductors carries the balanced audio signals. Twisting the conductors together works with the balanced input to reject electromagnetic interference, and connecting the shield to ground provides protection from electrostatic interference.
Unbalanced interconnects
There are two types of unbalanced interconnects commonly used in audio:
- RCA cables
- 1/4" T.S. cables
(1) "RCA" cables are most commonly used in HiFi stereo systems and are constructed with coaxial cable. Most connections of this type carry -10dBV line level signals; although the similar cables are be used for lower level vinyl phono level signals.
(2) 1/4" T.S. cables are most commonly used in home recording systems to interconnect equipment such as desktop mixers and outboard gear. Music instruments also use this type of interconnect; for example, a "guitar cable." Both of these types of interconnects are typically constructed using coaxial two-conductor cable. The center conductor carries the signal voltage, and the outer “shield” conductor carries the signal return current as well as serving as an electrostatic shield.