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Mobile Fidelity's Geo-Disc Cartridge Alignment Device
Analog Accessories by Mobile Fidelity
Available Again from Mobile Fidelity Sound Lab! NOTE: Only work with Straight-style tonearms. Will NOT work with S-Shaped tonearms.
Mobile Fidelity succeeds in bringing cartridge alignment tools to the masses. The Geo Disc is a simple to use, accurate alignment protractor for setting cartridge measurements. Achieve critical alignment within .003 of an inch in moments, not hours! The Geo-Disc exclusively addresses the three most important factors of alignment: Proper offset, proper tracking and proper overhang.
Directions for Use:
1. Mount cartridge in headshell but do not tighten mounting screws completely; balance arm and set recommended tracking and anti-skate forces.
2. Place Geo-Disc on Turntable.
3. Move your eye close to the sight-line ("A-B") and sight along the small ridge atop ("A-B"); rotate the Geo-Disc so that the ridge points directly at the center of the tonearm lateral pivot point. Then use a piece of adhesive tape to keep Geo-Disc from turning.
4. To set proper overhang, adjust cartridge in headshell so that, when gently lowered onto grid ("C"), the stylus rests directly in the small indentation in the center of the white circle on the grid ("C").
5. For proper offset angle, look at the front and sides of the cartridge body relative to the grid; raise stylus off Geo-Disc and twist cartridge in the headshell so that front and sides of cartridge are squared with the grid. Recheck Step #4.
6. Final offset angle is achieved by sighting along line ("D-E") - the stylus shaft should appear to be in line with ("D-E"). If not, twist the cartridge to the proper position. Recheck #4.
7. Tighten mounting screws. Recheck Step #5.overhang.