I don't know how long tubes last, or their cost, as I bought my first tubed amp,a McIntosh MC 2000 some 8 months ago. A lot of tubes on this one, but I had a KRELL FPB 300 SS amp and I will tell you it ran WAY HOTTER than the Mac. The Krell sounded great, and made an even better space heater. I have found the heat from the Mac a non-issue and I have a rather small room. Plus the sound of the tubes...so smooth!
