Well, I did my first gig with my B2000 last night, and noticed some of the things that others have posted. I used a B1500 for years, and sold it because of it's weight a while back. Thought I'd try a B2000, and have to say I love the tone. However.....it just doesn't seem to have the "balls" & power that the B1500 did! I was in a familiar venue, using same bass, same band. With the 1500, I usually had the drive at noon, and never needed the master past 10:00.....most tone controls close to flat. I set the drive at noon on the 2000, dialed in my tone (fairly close to where I used to have the 1500), and ended up needing my master past noon! I'm surprised, and wondering what gives? I do love the tone, and especially the weight.....
You seem to be talking gain structure not power. The relative position of the controls has little to do with what different amps are actually putting out.
Yes in the latest generation of Carvin amps (B2000/BX1500) the drive control IS part of the gain structure. On my BX1500 I need to have the drive on 9 to get my sound. Also I've done some tube rolling and noticed everything (related to gain) changes with each tube. I ended up going back to the stock tube as that one works best for me.