Palmer PMAIN Passive 2-Channel Line MergerSometimes it is necessary to send two stereo signals to one device, for example, when two mixing consoles have to drive a stereo power amplifier. In practice, this is rarely possible without ground loops occurring. The Palmer main solves this type of problem. It mixes two stereo input signals via a resistor matrix, whereby the input pair A is galvanically isolated by a transformer in order to avoid ground loops. The Palmer main works purely passively.