The effect itself seems to work fine. I did the offboard wiring in a way that the Input of the board is wired to ground, when the unit is off.
But unfortunately I get an extremly lout pop when I switch the unit on and off. I double checked the layout, no mistakes here. I also disconnected the LED and it still pops.
I noticed that there is a 1M pulldown in the layout right after the input, I checked its value and its correct. I also added another 1M pulldown at the end of the circuit. Seems like this helped a little with the "switching off pop" but its still very loud when turned on.
Last thing I tried is to replace Transistor and a few capacitors, but no improvement at all.
If this helps: The popping goes away if I disconnect the overdrive board input wire from the 3PT switch
If the 1M resistor at the input is located after the input cap, it is not a pulldown resistor, but a bias adjustment, and you then need to add a 1M before the input cap, for it to function as a a pulldown resistor.
If that does not help, you could try to lower the value down towards 470k and see if that helps...
The 1M resistor at the beginning of the circuit comes directly after the input and is parallel to the capacitor, so I think it indeed is a pulldown resistor.
I changed its value to 470k, now there is that and also a 1M at the end of the circuit. Unfortunately, it still pops.
It got better, but I use that overdrive more as a boost and therefore having Gain all the way down and Volume pretty far up. So there the pop is still too loud...
I also rechecked the solderings, they seem fine. The only things in sockets on that board are the two ICs and the transistor, I doubt that there is a loose connection on them. I also think that a loose connection on the transistor or IC would not give the pop but more of an interrupted signal while the unit is on.
IvIark, what kind of buffer do you mean? In front of the board?