© March 17, 2013 Christopher Cozad
To replace an onboard preamp / pickup system with an L.R. Baggs Anthem stage pro where the existing opening in the side of the guitar is too large for the new preamp. In this case, the preamp being replaced happens to be an older L.R. Baggs OnBoard Element. This is intended to be a ‘one-way trip’ that is to say, there is no intention of returning to the Element at a later date (although it could be possible to do so). The guitar is a carbon fiber Rainsong WS-1000.
Both pickups, side by side. The Anthem (on the left) is a smaller overall design.
View of the opening in the side of the guitar with the OnBoard Element pickup removed. The replacement pickup will require a much smaller cutout.
Create a ‘reducer’ to solidly house the new stage pro preamp, successfully span the existing opening and follow the contour(s) of the upper bout.
While a variety of materials could be used for the reducer, such as bent hardwood, plastic (flexible - not brittle), or metal, I chose to use a piece of 1/8" plywood (the type available at most craft stores). This material would be easy to sculpt, have sufficient strength, and be bendable. The first step was to size the reducer appropriately. In my example, it ended up being 3" wide and 4.25" long. Those dimensions were determined as an average of what was necessary to span the existing hole in the guitar, provide sufficient support for the new preamp, and look somewhat like it belonged. I gently contoured both ends of the wood following the contour of the stage pro housing ring for a pleasing appearance.
The flexible housing ring that is supplied with the stage pro must ride atop the reducer, so the next step was to cut an opening in the reducer to fit that ring. This involved making a paper template to trace the opening, drilling a hole, fitting a coping saw blade through it and removing the interior wood. The dimensions for the opening are 1 57/64" (4.8 cm) wide by 2 3/4" (7 cm) long (note the ‘top’ is slightly radiused while the ‘bottom’ of the opening remains flat)
After sawing, the reducer begins to take shape.
The existing hole for the old preamp needed to be resized in order for the stage pro to fit flush with the outside surface of the guitar side, as opposed to sitting behind the side of the guitar (the manner in which it is designed). The reducer rides atop the side of the guitar, and the stage pro housing ring is sized in depth to accommodate the thickness of a guitar side (effectually ‘pinching’ the guitar side between the housing ring and the preamp), not a guitar side plus the thickness of a reducer. Carefully support the side material of the guitar while using a file or sandpaper to remove only the minimal material required for the preamp to ‘wedge’ in the opening.
Here are a few shots of the Anthem preamp, with and without the housing ring (Note that the preamp dimensions are approximately 2 1/8" wide x 3 3/8" long x 2 1/4" deep):
Fit the stage pro housing ring into the reducer and drill the 4 holes that will secure the preamp to my plywood reducer plate using a 1/8" brad point drill. Determine a functional and aesthetic placement for the 4 additional holes that will hold the reducer to the guitar body.
The next step involves drilling 4 holes in the body of the guitar. Make certain you support the guitar sides while drilling. I used the same 1/8" brad point drill which will allow for the use of #6-32 x 3/8" long stainless steel bolts with lock nuts to hold the reducer in place.
Fit the preamp into place. Reach into the soundhole and press the preamp up against the reducer plate.
From the outside of the guitar, press the Baggs housing ring into place and secure it to the preamp with 4 screws.
Dexterity was the only skill required at this point, where everything was carefully assembled and tightened. Once in place, I connected the UST, Microphone and output jack. The strings were put back on. I ran a cable to my L.R. Baggs Venue and tuned the guitar. I released the Mute button on my Bose L1 Model II Tonematch Audio Engine (mixer) and the Anthem sprang to life, lending that extra mic'd quality to the guitar that Baggs does oh so very well!
The Rainsong sounds great! I think the small addition of wood to my carbon fiber guitar was just what it needed! ;~}