This article describes a method for safely connecting the output of a Nexia, Audia, or Tesira to another device with phantom power enabled on its input side.
Audia, Nexia, and Tesira mic/line outputs are not phantom-power tolerant. In order to safely connect them to a phantom-powered input the solution is to capacitively-couple the Audia/Nexia/Tesira output to the device.
Schematic and parts
For applications with 12-volt phantom power we suggest using Nichicon UVP1V102MHD capacitors. The Nichicon UVP1V102MHD are Digikey part number V102MHD-ND and are available from Digikey in piece quantities.
Note, please, that if the Phantom Power voltage is the full 48-volt, then the capacitors will require a higher rating. We recommend Panasonic ECE-A1HN471U which is DigiKey part number P1287-ND, 470uF @ 50V. These are also available in piece quantities.
The diagrams below show how to connect the capacitors in both the 12-volt and 48-volt case.
One may very well ask why Biamp does not make its outputs phantom-power tolerant.
The answer is that doing so would necessarily degrade audio performance. The capacitor solution suggested above will – albeit very slightly – degrade performance. The vast majority of users don’t need outputs that are tolerant of phantom power, so we prefer to not include it and, instead, to maximize our audio performance.