This circuit was published in a recent magazine as a past project. It is a crystal radio from October 1986 Radio Electronics magazine. The article detailed the assembly.
The circuit shown in the figure is suggested by Maxim (www.maxim-ic.com) and makes use of the...
This preamp with several inputs using germanium transistors from the time was found in Japanese...
This circuit was found in the Intersil Databook. The integrated circuit used is uncommon today. R2 sets...