This circuit with 10 MHz and 1.25 MHz TTL outputs was found in an American documentation from the 1980s. The used integrated circuit is uncommon today.
This circuit is suitable for low impedance m icrophones. Gain is given by the 2M2 resistor. This...
This sensitive circuit was found in old documentation. The SCR can be any of the 106 series and...
This preamp with several inputs using germanium transistors from the time was found in Japanese...