Acoustic Bass Preamp Replacement

Use a guitar string winder to carefully remove each string.

Look inside the bass for the preamp tuning box.

Once you find it, unplug the small jack.

Cut the zip tie holding the excess length of wires in place. This is located inside the bass.

Pull out the pick-up stick from the bridge of the base.

Look for the tuner/equalizer/preamp and carefully remove each screw using a Phillips screwdriver.

Once screws are removed, look for the endpin jack and remove it.

Place the tuner over the area you removed the previous one from.

Scratch a line around the opening to the area of the bottom portion of the tuner.

Using a metal file, file up and down, following the outline.

Continue this, going around the outline until the desired opening is made.

Get your output platform and measure, with a ruler, the perimeter of the parts under the face with the screw holes.

The second and third images show the underside of the part, measuring around the internals.

Use a pencil and paper to outline the measurements jotted down.

Cut the shape out using a pair of scissors.

Place the paper over the opening on the guitar and trace the perimeter of the paper.

Insert the file into the opening and file up until you reach the outline you traced.

Then follow the outline until the opening is completely cut out.

Place the preamp into the opening and screw into place with your power drill.

Using your power drill and the other four screws, drill the screws into the output platform openings.

Get your pickup stick and insert it into the hole in the bridge.

Look into the guitar for the end of the pick-up stick and pull it until it reaches the preamp box.

Plug in the pickup stick jack into the box, as seen in the fourth image.

Look for the preamp inside the bass. You will find a wire showed in the first image.

Stretch your arm into the bass to reach the output platform and find where you will need to plug the wire into.

Ensure the wire plugs in the right way and is firmly plugged in.

Use a zip tie to secure the extra length of wire inside the bass.

Replace the old strings or install new strings to the bass.

Use the string winder to make this step a lot faster.