This circuit was presented in a January 1990 Radio Electronics magazine article as part of a home theater sound effects system. It consists of a 3 kHz high-pass filter.
This 50's setup has a balance control. The transistors are germanium types of the time, and the...
This circuit has been found in an old American documentation, but can be easily implemented with common...
This circuit was found in a publication by Gernsback from 1960. The circuit generates signals from...