Esprit Celesta XLR ES Link Interconnect

The ES-Link signal path behaves like that of a single ended connection (RCA) with two of the leads carrying the same information, resulting in higher gain.   It also negates the typical advantages of an XLR cable, making it more susceptible to outside interference and therefore requiring (or suggesting) the cable be shielded.

Historically, ES-Link (also referred to as ESL-A) ran exclusively between an Esoteric source component output stage and the input stage of an Esoteric preamp stage included either on an integrated amplifier or a stand-alone preamplifier outfitted with ES-Link connectivity.

In the latest generation of products, the ES-Link signal path was extended; now running from the output stage of a preamplifier into the input stage of a power amplifier.

Because there will be those customers using an amplifier from a source other than Esoteric, the engineers purposely reversed the male and female XLR connection points in order to prevent accidentally connections to the wrong signal path.

Found here below are two illustrations.   The first is a block diagram of the signal path  The second is a written illustration of how ES-Link works.   It is a lot of information, but perhaps a better explanation.

ES-Link Analog – Esoteric’s unique current transmission
ES-Link Analog is Esoteric’s proprietary current transmission method. By connecting devices that support this method, it is possible to reproduce the sound as if it were being played directly from an analog console in a recording studio. The sonic signature of ES-Link Analog is powerful, live and dimensional.