I remember using old scopes and oscillators that allowed for course/fine scaling using either two separate knobs or one dual-concentric (if that's the term) knob. I am sure that my question has been asked/answered before, but thought I'd check here. Why can't an amp master volume control only have one knob? Why not a vernier knob, also? We all know what it is like to dial in an amp at super-low levels smoothly, without seeming to jump between levels. The amp I'm using is an ODS type, where changing the level of any knob other than the master volume often changes the sonic character, whether intentional or not. There are a number of different ways of controlling OD. I'm upstairs at 1:00 AM, trying to work with a new guitar, but at a level that won't wake my wife. I've been doing this kind of thing for years, and really wouldn't mind having a vernier knob for the master volume. Is my thinking unrealistic, impossible, etc.? I'm hip to the many ways of controlling loudness, but in this one instance, I'd really like a vernier knob. Even if I have to get a plastic knob and tape it to the amp. To be clear, I'm thinking of having the master volume at, say, 2, but wanting it at 2.2 or whatever is desired but unobtainable with the master volume knob.