Isolated metal DC jack questions...

[ACS]

So, I've got a build that's using a metal DC jack (through necessity - there simply was not enough space to fit one of the large plastic ones in there).  I always use the plastic I/O jacks anyway, so it doesn't really matter electrically - even though the case is at 9v potential, the PS still can't short.

This aside, what other issues could I be introducing? Given that the case is not grounded, does this mean I could be introducing unwanted noise into the circuit?

[petemoore]

case is at 9v potential
  "Gnd." is a relative term = a reference voltage.
  A battery or floating power supply is otherwise floating=no ground connection.
  The ground is assigned by the signal cable-sleeve only, this breaks 'ground-loop'.
   So...the circuit only cares about what it's seeing, and polarities [NPN/PNP etc.] + or - from ''Gnd." can be used to power the circuit, when assigned as such: Gnd. only sees 'a rail-reference'...which happens to be 'ground' for stompboxes mostly, ie a stake is driven into/literally connected to the earth via moist dirt or waterpipe.

[Hides-His-Eyes]

If the pedal touches another pedal... Zzzzzap.

[twabelljr]

If the pedal touches another pedal... Zzzzzap.

+1. Murphy will show up eventually and something grounded will fall on it or bump into it. Do you have room to insulate it with a rubber grommet or some washers with a lip to insulate the sides and the the pass-through hole?

[ACS]

Yes, that's definitely the kind of reason I was looking for!

Have used rubber grommets in the past, but don't have enough room in this build unfortunately... Have enlarged the hole, insulated the barrel of the jack and grabbed some fibre washers. Now insulated 

Thanks guys.

[R.G.]

Not to mention that an ungrounded case doesn't give you the same RF shielding that a grounded one does.