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 can be found in a 1970 Motorola documentation. The circuit can be implemented with general...
This circuit generates sinusoidal and cosine signals of 2 kHz given basically by the values of C1...
This circuit of a 1991 PE Hobbyst Handbook allows the brightness of the incandescent lamp to be...