Simple MD Catridge Preamplifier

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Phonographs are
gradually becoming a rarity. Most of them have had to yield to more
advanced systems, such as CD players and recorders or (portable)
MiniDisc player/recorders. This trend is recognized by manufacturers of
audio installations, which means that the traditional phono input is
missing on increasingly more systems. Hi-fi enthusiasts who want make
digital versions of their existing collections of phonograph records on a
CD or MD, discover that it is no longer possible to connect a
phonograph to the system.

However, with a limited amount of circuitry, it is possible to adapt
the line input of a modern amplifier or recorder so that it can handle
the low-level signals generated by the magnetodynamic cartridge of a
phonograph. Of course, the circuit has to provide the well-known RIAA
correction that must be used with these cartridges. The preamplifier
shown here performs the job using only one opamp, four resistors and
four capacitors. For a stereo version, you will naturally need two of
everything. Any stabilized power supply that can deliver ±15V can be
used as a power source.