With this circuit you can produce the sound effect passing from one channel to another. The circuit is from Mullard documentation from the 1960s. The transistors may be the BC548.
This basic 100 kHz oscillator is suitable for use in calibration. We found it in documentation from the...
Found in a 1968 EEE, this circuit accepts frequencies from 1 to 1000 Hz and control voltages from 0.1 to...
National Semiconductor suggests the circuit shown in the figure for amplifying signals from two...