Build Notes

C1 was originally a silver mica capacitor but these can be quite expensive, but a ceramic capacitor will work as well. Electrolytic capacitors can be used for C4 and C6. The original transistors can be hard to find as they are no longer manufactured, but a common replacement for Q2 is the popular BC108 or 2N3904. For the germanium Q1 you can try a different low gain (40-60 hfe) PNP. I suggest socketing these so you can swap them out easily if you want to test a few different ones. Check the datasheet online for your transistors for the pinouts!

The pinout on the PCB is:

Board Connections

The PCB connections are labelled as the following: I - Input, O - Output, V - 9V DC in, G - Ground Potentiometers are connected from pin 1 to the square pad on the PCB.

This board was designed so you can use right-angle board mount potentiometers on it if desired, otherwise you will need to solder wired from the pads to the correct pin/lug.

Jack sleeves and DC centre pin should be connected to ground. V, LED + with a 2K2 resistor in series should be connected to the positive pin of the DC connector.