The tubes in my Modulus3, 3A and 3B all lasted between 2,000 and 3,000 hours. Yes, AI runs the tubes hard, but if you buy the factory specified tubes, you will get the tube life I got out of them. It’s when you buy tubes other than what AI recommends that can get you in trouble. I ran the Modulus series from 1992 to 2015. I would still own the 3B if it wasn’t for those stepped volume controls which made the music too loud or too soft for the amount of level the preamp put out.
