We found this circuit in a Radio Electronics from October 1963. The circuit uses an output transformer with a center tap. The trimpot is adjusted for higher gain and lower quiescent current.
The integrated circuit used in this 80's differential amplifier is a quadruple version of the 741...
This circuit was published in a January 1971 issue of Radio Electronics to check television...
This circuit was discovered in an English publication in 1979. The circuit can still be assembled with...