Okay.... The amp has this sound coming from it. It is at one volume, none of the preamp controls affect it. The volume controls do not affect it. It sounds almost like a broken record. It has this thick wooshy sound and a consistent crackel. I changed out all power tubes, no change. I switched out all preamp tubes, no change. Hitting [gently] the side/top of the amp does nothing to affect it. Touching/moving any outer componentry does not affect it. It is moderately loud and again, the volume controls, plugging in an instrument, nothing, nothing changes it. What do you think? Thanks!