Ground Question with PP2+ & Digital

[planethood]

I think I have a ground loop in my rig and I am troubleshooting one of the thousands if issues it may be.

I am using a PP2+ to power all my 9v pedals in my rack shelf. These pedals are placed in a RJM Gizmo switcher (had a GCX but needed more loops) in loops before my preamp. I am also using a Digital to power four other effects: Strymon Möbius (before preamp), Strymon Timeline (post preamp in parallel loop with RJM mini mixer), RJM mixer (post preamp) and Shure SLX wireless (before preamp which feeds into the switcher).

I have two questions:
1). The power supplies are zip tied to some rails on the rack. Is it possible that they can create a ground loop this way because the metal on the supplies are touching the chassis?
2.) Does it matter that some of the outlets from the Digital are supplying power to different devices in different parts of the signal chain (as listed above)? Furthermore, the Shure wireless is a reverse polarity device (the only one that is). Could that cause problems?

I realize that ground loops and rig him is a complex topic, but thought I would start with some of the basics regarding power first....

Thank you!

[JulianShur]

I would check all your cables, both long and short. A lot of the time, a cable is poorly shielded, damaged, something like that. All the outputs of the Pedal Powers are isolated, so unless you're sharing outputs with multiple pedals that shouldn't be the issue. Strapping them to the rack also shouldn't be the issue, because everything should be grounded, unless you have a piece of other equipment that isn't grounded. Sometimes older plugs with only 2 prongs and no grounding prong cause issues.

I would check cabling, and try omitting certain loops to narrow it down.
Hopefully that helps.

[planethood]

How are all the voodoo supplies grounded? Are they grounded to the enclosure chassis or just through the power plug?

I have a Voodo Pedal Power AC, PP2+ and Digital in my rig. I'm still in the troubleshooting phase...

[JulianShur]

Well its got the 3rd power pin, so it should shunt any transient current to ground. If you think you might have a ground loop, try insulating any chassis contact with a piece of fabric or something.