Hello, I want to build in my bass a switch to turn on en off my battery, beside the active sysstem I build a passive circuit with 2x vol pots en 1x tone. I have scheme and soldered this in my bass, know when I turn off the battery, I hear no plop, but when I turn on the switch I still here a plop. Does anyone have some advice how to correct this?
http://home.tiscali.nl/kuvvers/anti-plop_schema%20engels.JPG

What kind of circuit are you powering?

I'm powering an Aguilar OBP 3.

Is the switch make-before-break? The Aguilar circuits are notoriously hard to stop from popping.

You may want to change that 470 ohm resistor; as it is, it draws 35ma, your batterys won't last long with that. I would switch it to some where between 3.3K and 33k (5ma to 0.5ma).