Well, I have had my Pre-Fender Bass 750 for 5 years. It has been in a rack since it was new. Never pulled out of the rack. I baby my stuff. In the last couple of weeks, I have noticed a pretty great decrease in power and in performance of the head. Could this be my Pre-Amp Tube going bad? Over the last 5 years we have averaged practice twice a week and played probably 300 shows. I always take the time to cool down the amp and I always carry my own gear.