There are a number of stompboxes that do not have “pulldown resistors” on the inputs and outputs. As long as the capacitors on those connections have very low leakage, there will be no problems with popping sounds when the pedals are switched on. As shown above, the dc voltages at the circuit capacitors that interface to the outside world should be 0v because no dc is able to pass.
The dc voltage that accumulates must be eliminated to stop the popping sound. It is frequently asked on the forums if the pulldown resistors can be placed on the jacks. The answer is “NO” and the next drawing will make it obvious why.
If the resistors are added to the jacks, they will do nothing to drain off the voltage when the pedal is bypassed and the leakage will still accumulate as a small voltage potential. The proper way to add pulldown resistors is mount them at the input of the circuit boards, as shown below.
The small charge is now leaked off through the pulldown resistors (shown in blue) and the input (or output) will have no voltage to cause pops as it is switched on.
Should your pedal still pop after the addition of the pulldown resistors, the sound may be coming from sudden voltage supply variations caused when the LED is switched on. There is another AMZ article that deals with this type of noise/popping.