This circuit was fond in an old publication of the years 1950. The transistors are germanium types and equalization is RIAA.
This circuit was found in a 1986 publication. However, it can still be easily assembled, as the...
This circuit was published in Radio Electronics magazine in June 1959. The circuit uses an...
This circuit is based on an old Siemens integrated that can now be found very easily. It allows the...