Heat up the soldering iron, and wait until it is at its desired heat level. It will be used in the next three steps, so ensure it doesn't overheat.

The soldering iron can cause severe burns if used incorrectly.

To solder off the white box with the red and white wire in the corner of the preamp, heat up the two metal studs on the opposite side of the preamp as shown, and gently pull the white box until it disconnects.