Isolator

Transformer balanced galvanic isolation

Isolator is your 4 HP solution for galvanic isolation between its inputs and ¼ TRS balanced outputs, interfacing your Eurorack modular system without electric connection with the external equipment, which prevents possible ground loop issues. Each channel has a ground lift switch, so some ground loop problems can be solved with this full/partial ground lift option.
If no signal is plugged to the right input, then the left input will be sent to both Left and Right outputs. “Level” knob adjusts output level for Left and Right channels.

http://www.happynerding.com/category/isolator/