Since most components have grounded ac power cords and most interconnects have grounds, every component has two earth ground and thus ground loops. The third wire would add additional ground loops. All of this is to satisfy Underwriters Labs on the off chance that you have a loose power wire within the component and are grounded when you touch the component. All of this ruins your sound.
There are three alternatives. One is buying only plastic bodied component with the exception of your preamp. Two is using cheaters on all but the preamp power cord. In Canada cheater are illegal. You could also cut off the ground on the power cords other than that for the preamp. Third is having very low impedance grounds to one point that has a low impedance to earth or buy the Tripoint Troy Signature with filters on each binding post and a excellent ground. This is great but very expensive.
There are three alternatives. One is buying only plastic bodied component with the exception of your preamp. Two is using cheaters on all but the preamp power cord. In Canada cheater are illegal. You could also cut off the ground on the power cords other than that for the preamp. Third is having very low impedance grounds to one point that has a low impedance to earth or buy the Tripoint Troy Signature with filters on each binding post and a excellent ground. This is great but very expensive.