User manual FISHMAN ADVANCED UNDERSADDLE PICKUP INSTALLATION

[. . . ] This continuous design allows the Acoustic Matrix to sense the motion of the entire saddle, rather than small sections. The job of aligning the strings with the piezo sensing material is eliminated with the Acoustic Matrix pickup. Please remember that custom length, string spacing or string number pickups are available from Fishman Transducers. Also please note that the methods and techniques described in this article are intended only for professional repairmen and luthiers. [. . . ] The backwards tilting saddle will be much better at resisting the tendency of the center strings to bow to the saddle forward and create a long "D" shaped saddle slot and its accompanying space between the back of the saddle and the back of the slot. The pickup will "see" more downbearing force and will sound better. As a result of better force distribution between the saddle and bridge, the bridge will remain more stable, resist distortion and bending, and sound more solid. (Remember Objective II?) Top swivels and tilts (ideally a ball joint) to match interior angle of guitar top. Knurled collar to adjust vertical height of jack. Threaded to allow vertical adjustment. Even though it's more trouble and it ain't historic, etc. , we're convinced that it does really improve the pickup installation and often, the acoustic response. As a bonus, this technique often helps us move the string take off point a little further back on the bridge, when needed to help correct "folding-up-sharp" intonation. Notched to clear back reinforcing strip. a - ROUTING A SLOT You will need a small plunge router to do the job. Make a base for the router with a 5-8° angle to achieve an angled slot. The jig bottom should clamp to the guitar's edges only, and not tend to squeeze out the belly shape in the top, thus accommodate the aforementioned screw jack. The guide for the router base must fit precisely to avoid slop in the cut. A nice way to locate the existing slot is with an undersize pin chucked in the router. Dropped in the slot, the pin is a quick set up tool for slot angle and ends. 4) Figure 3 - JACK-Internal jack used to prevent movement of top during critical routing of saddle slot prior to pickup installation. 4. No end mill or router bit is capable of cutting a slot width identical to its diameter. One way to beat this is to send a set of bits to your local cutter grinding shop. For a couple of dollars they will reduce the diameter of your standard 1/8" and 3/32" cutters by about . 010". These reduced cutters can be used first and followed by full size bits to kiss off the final few thousandths, resulting in a beautiful "wall" surface that will be very close to being "on size". In lieu of a reduced cutter, I like to use a 7/64" (. 109") two flute spiral end mill. There's lots of chip clearance, lots of positive rake to cut cleanly, and less tendency to bounce around in the slot full of chips. Speaking of chips, the best cut will be had by directing compressed air right at the bit to keep the slot clear and the but cutting freely. We recommend Ekstrom-Carlson bits, available from your local E-C distributor (call 815-968-0961). 1/4" diameter shank for use in standard router chuck Turned smooth to . 090" diameter 3/32" x 9/32" long x 1/4" shank PART # 011-0309 1/8" X 3/8" long x 1/4" shank PART # 011-0412 FIQURE 4 - PIN LOCATES SLOT WITHOUT RISK OF DAMAGE. UNDER SADDLE PICKUP INSTALLATION . . . Just walk over to your milling machine and put the acoustic guitar jig in the vise. There's no end to the utility of a milling machine in any small shop, especially a repair/builder's shop. [. . . ] EXCEPTION: Pickups in guitars with a very steep string break angle (25° or more), will generally perform well, even if the saddle slot depth measures more than 50% of the total saddle height. PICKUP AND SLOT WIDTHS A 3/32" pickup should be used only in slots under 1/8" wide. If the slot is over . 110" or so, it's best to recut for a . 125" saddle and wider format pickup. This is often convenient when correcting too-sharp intonation by moving the back wall of the slot towards the back of the bridge, as a substantial improvement can be made in saddle placement, without patching and recutting the original 3/32" slot. CUSTOM PICKUP LENGTHS Pickups can be custom made to fit all instruments with saddles. strings, very wide or narrow six string spacings, "split" or multi-piece saddles and custom colors. [. . . ]