The transistors in this 1978 circuit can be BC548 and 1N4148 diodes. The electrolytic capacitors can be 47 uF and the effects are adjusted in the potentiometers. The circuit must also work with 6 V and its output must be connected to an audio amplifier. The 20k potentiometer can be 22k which is the current commercial value, just as the 2M potentiometer can be 2M2.
