Floating Unbalanced Line

A quasi-balanced output stage consisting of an unbalanced output connected to the tip of a 1U4″ TRS (tip-ring-sleeve) jack through an output resistor (typically in the 50-300 ohms range). An equal valued resistor is used to tie the ring terminal to signal ground. The sleeve connection is left open or “floating.” Thus, from the receiver’s viewpoint, what is “seen” are two lines of equal impedance, used to transfer the signal. In this sense, the line is “balanced,” even though only one line is actually being driven. Leaving the sleeve open guarantees that only one end of the shield (the receiving end) will be grounded; basically a telescoping shield – a practice that often significantly improves ground loop problems in balanced systems. For trouble-free interconnections, balanced lines are generally the preferred choice.