Absolutely never lift grounds. You are taking out of action the method used to protect you. If you have hum or noise, then you should investigate each unit individually until you isolate which piece of equipment is causing the ground loop or hum and fix it. Lifting the ground may mask the ground loop or hum problem, but you have now introduced a potential for serious injury or death. No joke! This is the same logic as taking a radio or hair dryer into the bath tub. Everything is fine until is slips out of your hand and falls into the water, then it is too late. You are asking for trouble lifting grounds. Find the problem and fix it. Lifting grounds does not fix the problem. There are many posts here that explain the method for isolating which component is causing the problem.
Enjoy, but do so safely and use common sense.
Enjoy, but do so safely and use common sense.