This preamplifier circuit for turntable cartridges was found in the March 1994 issue of Electronics Now magazine. The circuit is suitable for magnetic cartridges.
Based on a CA3059 zero-cross switch, this circuit was found in the July 1995 Electronics Now...
This 1986 documentation circuit provides 3, 4, 5, 6 V voltages under 350 mA for powering walkmans...
We found this circuit in an old publication. The circuit can be implemented with modern equivalent...