TK7Ea Signet Scientific Dual Magnet Stereo Phono Cartridge

The Georg Fisher / Signet Scientific TK5Ea / TK7Ea / TK7LCa Dual Magnet Stereo Phono Cartridges represents outstanding performance, due to the Dual Magnet construction used to translate the stylus tip motion into two electrical signals. Unlike other designs, Signet cartridges employ twin tiny independent permanent magnets mounted at 45° to the record surface and perpendicular to the walls of the record groove. With its associated pole pieces and electrical coils, each magnet becomes an electrical generator reproducing only the signal from one side of the groove wall. Because each magnetic system is truly independent, stereo separation is maximized.

When just one channel is modulated, only the magnet for that channel is significantly displaced by the stylus. And because each magnet is substantially less than half the mass of typical single magnets used by others, the effective mass moved by the stylus is greatly reduced. The magnets, which are still one of the heaviest parts of the moving system, are mounted very near the fulcrum point of the stylus assembly. This design feature also reduces effective moving mass, without spurious resonances in the audio spectrum. This reduced mass also contributes to long record life by reducing the force applied to the record groove walls.

To further reduce effective moving mass, Signet cartridges employ specially designed cantilevers. Created from light-weight aluminum alloys or beryllium, these cantilevers provide great rigidity and lower effective mass.