Originally Posted by
Simon Barden
It's not just the low currents, it's also the relative size of the wires, PCB tracks and the short distances. Even with higher currents, ground paths of 3-5cm won't produce much of a volt drop at all. And the distances will be similar, and so will any resulting volt drops. What you end up with in a pedal are a few ground paths in parallel that have a common input connection point and a common output connection point, so there's not a lot of scope for measurable potential differences at the circuit connection points. But obviously at least one good ground connection to the enclosure is required so that it stops external noise from getting in.
On the Tone City mini-pedals that Andertons sell, the input and output jack sockets don't have a permanent ground connection to the enclosure. It's only when you insert a jack plug that the connection gets made. PCB-mounted jack sockets that just fit and holes cut in the enclosure, which all saves assembly time and keeps costs low.