True bypass: grounding designs

[Doum]

Hi everyone!
I've been thinking about true bypass wiring designs and I'm wondering which one of the following would be the best:

Design #1

Input and output jacks sleeves are in contact with the enclosure.
Ground for the circuit is taken from the input jack sleeve.
The grounding path from input to output is provided by the enclosure.

Design #2

Similar to design #1, except for the output jack which is isolated from the enclosure. A shielded cable can be used to connect it to the footswitch.
The grounding path from input to output is provided by the shielded cables.

Design #3

Here, both jacks are isolated from the enclosure.
The enclosure is grounded at a common ground point (e.g. a ground lug on footswitch shaft).
Again, the grounding path from input to output is provided by the shielded cables.

By the way, are shielded cables of any interest for hum/tone-sucking reduction?

Thanks in advance for your insight on these wirings!

Bye,
Dominique

[panterafanatic]

Shielding/unshielded shouldn't matter much since the metal enclosure should block interference, it would be more a of concern while out in the open. e.g. From your guitar to the pedal, especially with passive pickups, the higher output impedance makes it a lot easier to "taint" the signal while using long cables. Active pickups have a lower impedance making them less of a concern, but why use a 50' cable when 25' will suffice?

[slacker]

I prefer to use number 3, but just with normal wire not shielded cable. The problem with 1 and 2 is that sometimes jacks come loose and then you loose connectivity, with number 3 even if both jacks come loose the pedal will still work fine.

[Doum]

I prefer to use number 3, but just with normal wire not shielded cable. The problem with 1 and 2 is that sometimes jacks come loose and then you loose connectivity, with number 3 even if both jacks come loose the pedal will still work fine.

All right, good point indeed.
I'm actually quite lost with all the ground loops theory... for instance, would it be bad to wire both jacks with hot and ground wires (like in designs #2 and #3 above) without isolating them (or one of them) from the enclosure?
Is the "star grounding" scheme beneficial in stompboxes ?

[Processaurus]

In theory, Design 1, I think, but with isolated input jack (but output jack isn't isolated, and grounds the enclosure there).  The idea being that you aren't adding the minor noise from the enclosure to ground in with the input signal's ground, which the input is referenced to.

In practice though, any of these will be fine.  Guitars are so noisy, worrying about this kind of thing is like using expensive gourmet imported sesame seeds on a Big Mac bun.