Serendipity input jack wiring

[stax]

Hi all.
May sound a silly question but why no ground wire on sleeve of the input jack on the layout?
Stax

[irmcdermott]

You can put one there if you want (i usually do), but the jack typically grounds itself through contact with the enclosure, given you are using a metal enclosure.

[stax]

Thanks I will put one on.