ABSTRACT
This chapter shows how to get within a couple of dB of the lowest noise physically possible using cheap opamps and a little ingenuity. The electronic noise will be much lower than the noise generated by the stylus sliding along a groove. The impedance of the cartridge strongly influences the noise performance of an moving-magnet RIAA stage. The frequency response of human hearing is not flat, especially at lower listening levels. Some commentators therefore feel it is appropriate to use psychoacoustic weighting when studying noise levels. This is almost invariably ANSI A-weighting despite the fact that it is generally considered inaccurate, as it undervalues low frequencies. The noise conditions for the RIAA amplifier are quite different, as it is fed from a very low impedance, plus probably a series resistor in series with the MC amp output to give stability against stray capacitances.
