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This Collings MF5 came in to have a pickguard fitted. As it is often played in large theatres and auditoriums a K&K Mandolin Twin Internal pickup system was also installed.
The Collings pickguard is smaller than the classic Loar F5 guard. It doesn't obscure the treble f-hole so much, and doesn't require the mounting bracket. Instead, it is supported on a carbon-fibre bracket. This is attached using two allen-headed bolts which screw into brass bushings installed in the treble side of the fingerboard extension. Drilling and inserting these bushes is the most nerve-wracking part of the process. With a mandolin of this quality there's no room at all for error.
Installing the K&K transducers inside the mandolin is fiddly but relatively straightforward. I use a small LED light and flexible mirror which can be inserted into the f holes. The transducers mount inboard of the f-holes, under the feet of the bridge. They do an excellent job, although as always a pre-amp or active DI box with a high-ohmic input (1 MegOhm) is required to get the best out of them.
Reaming out for the gold-plated Switchcraft endpin jack was harder than on a guitar. As well as cutting through the wood of the endpin it's necessary to open out the hole in the tailpiece. This can safely be done with a hand-held tapered reamer, though they can go off-centre. I used a step drill, which offers a range of diameters up to 1/2" (pictured below). These are titanium-coated and designed for punching holes through steel plate or aircraft-grade aluminium, so they make a very neat hole in the brass or bronze of mandolin tailpieces.
Another option is to use the Vintage Jack range, which fit directly into the existing tapered endpin hole. They are custom-built and very high quality, so they are an excellent choice there it's important to retain the integrity of the instrument. However, they use 3.5mm mini-jacks rather than standard 1/4" jacks, which can be a concern when gigging. As K&K note on their website, the smaller connector cannot offer the same reliability and durability as the standard jack system.