Things You'll Need
Instructions
Open the metal detector housing to expose the wiring. This is the area where your factory sensitivity controls are placed. Depending on the model, opening the housing will vary widely.
Unhook the return signal wire. This is the largest wire running from the coil to the sensitivity control. Unhook the ground wire. This wire -- if not labeled -- will be small and typically either green or white.
Hook the return signal wire to the amplifier at the area indicated. As all amplifiers vary, the placement of the wire will vary. Typically, this is the largest connection point or otherwise labeled as "return signal input."
Connect the ground wire to the amplifier. This is done in the same manner as in step 3, only this is usually screwed onto the amplifier body.
Attach the amplifier to the detector housing by screwing it onto the housing or attaching it securely with something else, such as electrical tape. Whichever you prefer or works best is sufficient.
Turn the detector on, then turn the amplifier on. Set the amplifier to its highest sensitivity and test for proper function.