ABSTRACT
Signal Levels from Vinyl Discs are usually no gain controls on Moving-Magnet (MM) RIAA inputs. An MM stage with a passive gain control after it is, of course, not the same thing, and quite useless for preventing overload with high inputs. There are some inflexible limits to the signal level possible on vinyl disc, and they impose maxima on the signal that a cartridge can reproduce. The absolute value of these limits may not be precisely defined, but they set the way in which maximum levels vary with frequency, and this is perhaps of even greater importance. Moving-magnet and moving-coil cartridges both operate by the relative motion of conductors and magnetic field, so the voltage produced is proportional to rate of change of flux. The cartridge is sensitive to velocity rather than to amplitude and this gives a frequency response rising steadily at 6 dB/octave across the whole audio band.
