For all you guys with a pre/power setup...how do you mute yourselves on stage - for instance when swapping basses? I've been looking into getting a pre/power setup, but couldnt find any sort of mute function on the ones I have been looking at, which is something that comes in very handy for me. Did I overlook something? Same goes with a tuner...are there any tuner inputs on the preamps if I were to get a rack tuner?