ABSTRACT
This chapter deals with the design of preamplifiers for moving-magnet cartridge inputs, with their special loading requirements and need for RIAA equalisation. Compared with modern digital formats, vinyl has a restricted dynamic range and poor linearity and is very vulnerable to permanent and irritating damage in the form of scratches. The most audible spurious noise coming from vinyl is that in the mid frequencies, stemming from the inescapable fact that the music is read by a stylus sliding along a groove of finite smoothness. Distortion gets worse as the stylus moves from the outside to the inside of the disc. This is called ‘end of side distortion’ because it can be painfully obvious in the final track. There are limits to the signal level possible on a vinyl disc, and the signal that a cartridge and its associated electronics will be expected to reproduce. The level reaching the preamplifier is proportional to the cartridge sensitivity.
