Is it safe to put an AC-DC PSU into a foot controller with ground lifted?

[Chance92]

Hello!

I am trying to build my first stompbox, but I am not sure if it is safe to do so. I want to put an analogue foot controller, a MIDI controller and an AC to DC power supply into one box, so that I can use it to control and power my BOSS GT-1000CORE, and carry them around with ease. I figured out the designs for the first two, but got stuck on the power supply.

At first I wanted to use an aluminium enclosure, but since the mains (wall power) would be directly connected, the enclosure need to be earthed at all times (I suppose?). I believe this would unavoidably create a ground loop if I connect the stompbox and my computer to the GT-1000 at the same time, because the computer is earthed as well.

Then I thought using a plastic enclosure may be a better choice. I can put a class II power supply into the case, connect the live and neutral to the power supply, which does not require earthing. I can then connect the earth wire to the 1/4-inch  jacks through a toggle switch. In this way, I can choose to lift the ground or not depending on circumstances.

I wonder if it is a good idea? Will it work or take away my GT-1000 and my life together?

[garcho]

Why not use a DC supply for the mains and daisy chain the foot controller and GT?

[Chance92]

Why not use a DC supply for the mains and daisy chain the foot controller and GT?

Thanks for you reply! The main reason is that I can't ground the rig with a normal DC power supply when the GT is not connected to the computer, and it tends to pick up a lot of noise that way. I also want to keep my rig as small as possible and save some floor space. 

[FiveseveN]

use it to control and power my BOSS GT-1000CORE

Do I understand correctly that you want to put a ROLAND PSB-1U (or equivalent), a MIDI controller and a foot-operated pot (for the expression control, I presume) in the same enclosure? With the option to connect the DC ground to mains earth, because it's noisy when floating (i.e. with headphones).

MIDI is isolated through photocouplers, so the connection would be made through the EXP jack. You can use a plastic jack to retain the option to lift the ground when using a metal enclosure.
Otherwise it should be fine if you're careful with the mains wiring.

[Chance92]

Do I understand correctly that you want to put a ROLAND PSB-1U (or equivalent), a MIDI controller and a foot-operated pot (for the expression control, I presume) in the same enclosure? With the option to connect the DC ground to mains earth, because it's noisy when floating (i.e. with headphones).

MIDI is isolated through photocouplers, so the connection would be made through the EXP jack. You can use a plastic jack to retain the option to lift the ground when using a metal enclosure.
Otherwise it should be fine if you're careful with the mains wiring.

Yes, that's exactly what I want to do. Thanks for your advice. A plastic jack sounds like a good idea. I'm going to look that up.