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.
We found this circuit in a European publication of the 1980s. The transistor could be the BC549. The...
Found in a 1963 documentation, this circuit employs germanium transistors of the time. Transformer and...
This circuit takes advantage of the temperature variation of the component with the air flow that...