I turned my Smallbox on this morning at church and no sound. I plugged straight into the amp, changed a preamp tube in V1 and tried different guitar and speaker cables. Nothing worked. When I got home it worked fine, but I noticed a popping noise when changing channels that I have never noticed before. I have since changed preamp tubes and the popping is still there. The amp sounds fantastic, but I still think the channel switching pop is new. It happens both with the amp switch and footswitch. I am hoping Dave or someone else might be able to help.....