Edit: resolved, was a faulty tube OP: So, I just tried to adjust the bias on my A318B, and came up w. some troublesome readings. The bias is meant to be .18v. One side needed a small adjustment to come into compliance, but the other was at .27. From what I understand, this not only affects the sound, but the life of the tube. Using the trim, I was only able to bring it down to .23. What gives? The trim pot doesn't go down any further. FYI, the amp was on for about 3 hours before I took the readings.