Electronics for Vinyl

Chapter 10

Moving-Magnet Inputs

Discrete Circuitry

Discrete MM Input Stages

Moving-magnet (MM) input stages constructed from discrete transistors have certain advantages. They are not limited to opamp supply rail voltages. They do not produce complex distortion products or crossover distortion like some opamps. The circuit operation is completely under the designer’s control, and every parameter, such as each transistor’s collector current, can be chosen by the designer. This chapter examines how to use that freedom of design and at the same time gives an historical overview of MM phono stages.

Discrete moving-magnet (MM) input amplifiers were almost universal until the early 1970s. For a long time opamps had, quite deservedly, a poor reputation ...