This is a simple tubed mixer from the 50's. The circuit does not include the power supply and has 3 inputs with independent controls. The tubes are double and the inputs are high impedance.
This circuit was obtained from an American 80's documentation. It can be implemented with modern...
We give in the figure a different application of 4013, which can also be used as monostable. In common...
We found this adapter in a 1970s American documentation on instrumentation. It is suitable for analog...