Wiring in an active/passive switch.

[Marty Forrer]

Is it as simple as interupting the output of the blend pot so one side goes to the pre and one side goes to the output socket? Would it be a DPDT switch? Trying to get my head around this.

 

[preci]

A DPDT switch would work great for this. If your pickups go straight to a volume/tone, then to the preamp; then as you described would be correct. Here's a wiring diagram.

 

[walterw]

^
that's the "old" bypass switching, it works but might be kind of noisy because it leaves the input to the preamp open when bypassed, allowing it to generate noise

the better switching (which is the same as "true bypass" switching in pedals) has the extra step of shorting the preamp input to ground when bypassed to properly silence it

("effect" is the same as "preamp" in this application, while "input" is straight from the pickups and "output" is to the jack)

 

[preci]

Ah yes, you are definitely right. I made some fuzz factory-style pedals this year and they had some serious noise in bypass mode until I discovered that schematic and rewired the footswitches.

 

[fig]

I redrew the wiring diagram that walterw posted and relabeled with "preamp" text. Added schematic below the wiring diagram. Made it for myself, but if anyone passing thru is interested, here ya go.