MIDI switcher ground question?

[G. Hoffman]

I'm making myself a MIDI switch/looper thing (THIS ONE, which is on a bread board working, so now I need to fit it in a box!), and I'm wondering if it is a good or bad idea to isolate the guitar signal ground from the logic ground.  Power is transformer isolated, and the signal switching is via relays, so by using isolated jacks the two systems don't really need to have any (electronic) relation to one another.  Though, come to think of it, they will share a ground through the amp function switches, which will be handled with a 4066.

My guess is I should try both, and see which is quieter, right?


Gabriel