Please start by turning off your dome and unplugging it. 

Next you will need to remove the lower rear panel, which can be done by loosening and removing the four nuts that hold it in place, which you’ll see circled in red in the image below.

After that you will see the current black audio booster box with a brand name “Donner” on it. Please unplug the power from the box so that it’s off. Next, simply remove the wire and plug that is running into the “Input” jack on the “Donner” box and plug it into the “Input” jack on the new “Behringer” box and do the same for the wire running from “Output 1” on the “Donner” box and plugging it into the “Output 1” on the “Behringer” box. 

Then plug the Behringer box into the and make sure it’s on (on the box you should see a yellow light that turns on), turn the volume knob from “Output 1” up to “10”. 

Next, plug the Somadome back in, turn it on, run a session, and let me know if you hear the audio playing loud and clear through both ears of the headphones.