This excellent tube preamplifier was found in Radio Electronics magazine from July 1958. The power supply was not included. The circuit has several inputs.
This circuit for cars with mechanical ignition systems was found in the Electronics Experimenter handbook...
This code practice circuit was found in a 1990s issue of Radio Amaterur Today magazine. It...
The circuit presented was found in the Linear Applications Handbook of the National Semiconductoir of 1994....