Found in a Philips' 1968 documentation, this circuit is slightly different from the previous one. The components are also from the era, and modern equivalents can be used.
This circuit was obtained in a 1991 Electronics Handbook. The publication no longer exists, but...
This circuit was obtained in a 1990 English magazine. The circuit can be assembled with equivalent power...
This simple preamplifier presents a high input impedance and can be used with microphones, piezo...