Today I received my B&W Bass Alignment Filter (BAF) and I am trying to put it in the tape loop of my SP3. The physical part was easy, but how do you "enable" the loop function? I run balanced to the amps so the single ended tape loop is ideal. I just can't figure it out and the manual doesn't mention it. I haven't used a tape loop since the 80's and back then it was a simple PHYSICAL button that was engaged.