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.
We found this circuit in the 1994 Linear Applications Handbook by National Semiconductor. The...
This circuit has more historical value than practical, unless the reader find all the components...
This circuit was found in documentation from the 1970s. It eliminates contact bouncing, providing...