Found in 1948 MIT documentation, this 4-tube amplifier is characterized by its low noise level.
This circuit was obtained in a manual for radio amateurs from 1975. It is a circuit that allows the...
This is the circuit of a commercial radio sold in Japan in the 1960s. The IF is 455 kHz, and the...
In this circuit found in a Texas Instruments 2016 documentation we have an adjustment for the...