Switchable Onboard Power +9v/+18V pop

[MAO]

I built the NE555 version of Switchable Onboard Power +9v/+18V using a stomp switch and I'm getting a pop when switching to 18vs, no pop when switching back to 9v.

I disconnected the "18v" LED to be sure that wasn't causing the pop, it wasn't.

I'm using this on a Plexi Drive.

Is there a known fix to stop the pop when switching between 9v/18v supply voltages?

[Neil mcNasty]

From what I have experienced, there will always be a pop when switching power (specially when stepping up the power), either if it's like in your case, or when switching bias resistors.
When dealing with switching pops from caps, this can prevented by adding a 1M resistors between thew lugs, but in this case I do not think that is recommended, as it will leak current.

Maybe there is a way to use a cap to smooth out the transition? but then I guess you will not get a instant transition between them, as the cap has to charge up before passing the current.

The Dwarfcraft Shiva pedal has a Stomp to switch in the Starve pot, and my build does not pop when switching. But it does not change the voltage too drastically, so maybe that is why it does not pop...