Hi guys. Im using a mackie dl1608 with ipad 1 in/out of dock. Usually i have it sat on my keyboard so i can make changes. The drummer also have a ipad 1 for click track, his lead out of ipad is stereo/left click to his drum monitor amp and right hand to the dl1608. The problem is there is a bang every now and then and when he touches the ipad a bang occurs. I have tried different leads and 3 different ipad 1's same thing happens