This circuit is from documentation from 1965 but can be easily implemented today using modern transistors. We can use BD136 for Q1 and TIP42 for Q2. The TIP must be equipped with a heat sink.
This is the circuit published in the August 1973 issue of Radio Electronics magazine announcing its...
This circuit can be used to add a delay to a logic signal as shown by the input and output...
This tone control was obtained in the Audio Handbook of the National Semiconductor of 1977. The...