Ok - So I just built this pedal. It took me a while to get to because I was building others first! I have built it exactly to speac and wired up the switch exactly as per every other Pedal PCB true bypass pedal I have built, ignoring the BP pad altogether and I get nothing. The LED lights, I get a bypassed signal when bypassed but absolutely nothing at all when engaged. And by nothing I mean no buzzing, no hiss - absolute silence.
When the pedal is bypassed I can touch the switch lugs with my finger and get the expected hum. When the pedal is engaged I get no hum whatsoever even if I touch the switch lugs, which leads me to think it's shorting out somewhere. I have inspected every single solder with a magnifying glass, reflowed a few which looked remotely dodgy but no response. I have no solder bridges, no dry joints, no missed connections and I tested the switch and it works.
Has this PCB been verified? I can't think what I could have done wrong! Of course I may have but I can't see it. Any clues?