We found this circuit in the October 1970 issue of Radio Electronics magazine. It uses the then-new CA3018 integrated circuit from RCA. Some resistors are required for best performance.
This circuit was found in a 1977 Radio Shack documentation. The unijunction transistor can be...
Other series amplifiers such as the MC3301, MC3401 and LM2900 can be used on this circuit. We...
This circuit offers excellent sound quality for headphones of 150 ohms or more. The circuit was...