I have purchased from his eBay store. Are you referring to his mute circuit PCB when you say “switch circuit”? I’m not trying to be pushy, I am genuinely curious about the PCBs you are using. For instance, the Elliot Sounds bleeder circuit; is that something you DIY’d or is that a project he offers (yes, I looked)?Pete has an Ebay store: https://www.ebay.com/str/pmillett