This circuit with RIAA equalization is from 1985 US documentation. The circuit has a flat response of 150 Hz to 40 kHz. The power supply must be symmetrical.
This circuit was found in a 1967 Raytheon manual. The transistors are from the time. Equivalent modern...
This circuit was published in a 1979 magazine, but it can still be easily assembled as the...
The circuit presented generates short pulses. This configuration was found in a publication from...