I have had my V-12 for six months or so and at tonight's rehearsal in the middle of a Beatles song it just quit. Tried different instrument, cables etc.. no avail. It will play for about ten seconds and then nothing. Both channels same thing. Has anyone had this problem? This is the second failure of this rig. I thought that almost 4K would buy the best and give sparkling reliability. So far my 1968 Fender Bassman outshines it.