Do you hear hum or noise in your audio setup with certain inputs? Most people would answer yes, and that's because in most installations the audio signals are not balanced. Professional equipment have balanced audio which uses a + and a - signal for each L/R side and therefore does not rely on ground. Any noise in the ground between the source of the Audio and what it is connected to is automatically ignored. On the other hand unbalanced signals, such as the one coming out of consumer equipment, have no reference other than building/AC ground. Line-level audio is a very tiny low-level signal, so any noise in AC ground, even as little as 0.004v, will be quite audible – yuck.
The unit is simply inserted in series with the audio and it literally eliminates the ground connection between the two sides, passes all the audio while filtering out any noise using high performance audio transformers.
In most cases the unit can be used in either direction, however it is designed so that the male RCA connectors on the molded cable are used as input and the female RCA connectors on the box are outputs. The input side incorporates DC blocking capacitors. Some audio source equipment may have a certain DC bias voltage on their audio output connectors. In order to isolate this Bias level from the transformer coils, DC blocking capacitors are employed by the GLI-RCA. The isolated output is automatically AC coupled and has no bias. Below is a picture of what is under the hood.
