I wish either Joseph or Victor would respond to some of these technical questions. I think they are hesitant in posting for fear of the moderators deleting this thread. I don't know how many hours my original cca had on them, but I'm guessing that they had quite a bit more than 2000 hours. I have a new problem now with my preamp. Last week, before I went to bed, I turned the system off, including my preamp, which is the standard evening procedure after listening. The next morning the preamp was on. I knew I had turned the switch to off and sure enough it was off, yet the preamp stayed on. I had to unplug it to turn it off. I emailed Joseph and he told me either a switch wire was shorted or the switch went bad. He sent me a new switch and I went ahead and changed out the wiring, but guess what? new switch doesn't work. Same problem. I tried to call Joseph, but apparently he doesn't return calls on the weekend.