I have just used the Feedback Machine today for the first time and the results were quite amazing:
I meditated for 10 minutes on a mantra, with the machine near me (feet not yet on the the plates), with the crocodile connectors attached to aluminum trays.
I immediately noticed a tingling sensation through my palms and near my feet something felt different in my meditation with the machine near me.
Once I had finished the mantra meditation, I placed my feet on the aluminium trays and listened to instrumental music for 10 mins. The results were intense and moving!
My feet tingled with energy and after a while this spread to my whole body.
After a while my head felt so light, my spine and neck straightend as if buoyant and being pulled up by a string! I was overcome with energy and gratitude and tears welled up and streamed down my cheeks.