Strapjack / Preamp Installation

If your guitar already has a half inch hole in the tail block, proceed to the installation.

Drilling the Strapjack hole

This jack requires a clean, half inch hole in the tail block of the instrument. The easiest way to drill this hole accurately and effectively is to use a half inch “step” drill-bit, available at any hardware store. Other options are to use a “Forstner Bit”, or a “Brad-point bit”.

CAUTION: DO NOT USE A SPADE BIT OR STANDARD DRILL BIT FOR THIS!

Begin by placing a piece of masking tape over the area to be drilled (generally, in the center of the tail block). This is to protect the guitar’s finish. Drill a pilot hole approximately 3/16” dia. Now you can finish up using the step-drill. Place the tip of the step-drill in the pilot hole, line up the drill as straight as you can, and proceed to drill until you’ve gone all the way through the tail block.

Installing the Strapjack

Remove the strap ring, retaining nut, and one washer from the end of the jack. There will still be one flat washer, one star-locking washer, and one nut remaining on the threaded barrel of the jack.

Adjust this nut and washers to a depth on the barrel that will allow approximately 90% of the smaller threaded portion of the jack to extend beyond the tail block outside the guitar. Bring the jack down through the soundhole into the guitar and insert it into the pre-drilled hole in the tail-block to check the adjustment. There should be a couple of threads remaining within the hole.

With the jack in place, lay the remaining washer over the threads and attach the external retaining nut until it’s tight. Finish by attaching the strap ring.

Upon completion, the small threaded section of the jack should be flush or near flush with the end of the strap ring. If the threaded section is recessed too far, the plug will not make electrical contact with the jack! Therefore, be sure to adjust this until it is right.