Pull-down resistors, input impedence and 3PDT switches.

Frequently asked question regarding resistors, potentiometers, types, requirements, ratings etc.
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Post by commathe »

Hey everyone,

I have been doing a lot of reading, in particular about input impedance lately. Generally speaking I like treble and so I want to attempt to make the impedance as high as possible. I've been realising however that pull-down resistors are generally going to bring your impedance way down (especially if you are aiming for something silly like 10Mohm input impedence). Anyway, I was having a look at my typical 3PDT switch wiring and I noticed I had a spare connection that would connect to ground when the pedal was off. This got me thinking, what if I attach my pulldown resistors to that? This way the pull-down resistors are switched in and discharge the input and output caps when the effect is bypassed, and then they are similarly switched out when the effect is engaged so that they don't effect the input and output impedence. I've attached an image. What do you guys think? Would this work or have I missed some crucial detail about pull-down resistors that means that they always have to be in the circuit?
wiring diagram
wiring diagram

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