A device that amplifies and/or balances signals to a line level suitable for transmission over long distances. Unbalanced audio signals cannot be reliably sent through long lengths of cable as they pick up too much interference along the way. Sometimes merely balancing the signal is enough to make it able to traverse longer distances, and there are many devices that do that, but in some cases the signal is either too low or too fragile to be able to reliably survive great distances (hundreds or thousands of feet). In these cases a line amp is employed. Line amps have very robust outputs capable of driving extremely long cable lengths into loads of varying impedance under adverse or high interference conditions.