Loud pop/sound when switching pedal on (dpdt)

[Mann]

I've got one pedal (diy) which emits a loud pop/sound when switching on.  What could help?

[smnm]

This is covered in the DIY FAQ on the top navigation http://www.diystompboxes.com/cnews/FAQ.html
Lots of info on there...

Bypass - I get a pop when switching my effect in and out. How do I stop this?

The typical method is to put a "pulldown resistor" from signal to ground at the front and end of your circuit. This is implemented as a 1 meg resistor from signal to ground. Just put one at the beginning of your circuit board (before the input cap or start of circuit if no input cap) and another at the end (after the output cap or end of circuit). Look at the many GEO layouts if you need to see a layout using these resistors. If you are not using high quality switches, it could also be the switch.

[Mann]

Thnaks, this was just what I was looking for.