After last week’s presentation of the new LL1545E we have received some questions on grounding issues and on how to connect the transformer.

The purpose of an input transformer is to provide unbalanced/balanced conversions, AND to provide galvanic isolation. If the incoming unbalanced cold is connected to the local ground (for instance to the chassis through an un-isolated RCA connector) the galvanic isolation is lost.

Below is a suggested schematic where the unbalanced input will give a +6 dB step-up compared to the balanced input. Note that we suggest that the ground from the source is not connected to local ground.