This two-tube circuit, one being a double, was found in Radio Electronics magazine from July 1958. The distance to the microphone depends on noise and losses. The cable must be shielded.
This circuit was found in February 1976, Radio Electronics magazine. The components are from the...
I found this circuit in a 1993 technical documentation. When we press the switch in parallel with...
This circuit provides two outputs of the same signal. One with the original phase and the other...