Hi, I got this question for homework at my sound engineering college. I researched for relay switches but couldn't find any helpful info. The question is: "You need to create a remote on/off switch for the amplifiers on stage while doing an installation of a sound system at the local club. The amplifiers must be switched on and off from the mixer position, without running thick power cables next to the audio cables between the stage and Front Of House. Explain the specifications for the relay switch to be used, the connections to this relay switch and the PSU to control the relay. Remember that we do not want to add any additional EMI noise to the sound."