Do not buy into the myth that volume controls are somehow calibrated for "volume". They aren't.
The only thing you know for sure about any volume control is that turning it one way gets louder and the other way gets less loud. There isn't any other relation between the numbers and the loudness.
So, if your amp, ANY amp, isn't loud enough, first check your instrument to be sure its turned up and not muted, etc.
If that is OK, the tones are set at middle or boost settings, and the volume controls are all turned to "reasonable" settings between 5 and say 7 on a 10 scale, turn up the LAST volume control in the system (usually the master volume). If you run out of control range before it clips or gets loud enough, go back to the gain or volume control and turn that up too.
If one volume or tone control is set way low, try setting it up farther first. You have to provide enough signal to work with first, set tones later.
Look at the clip and limit lights to see that you haven't run out of power amp capability or preamp headroom.
That usually will get you to max clean volume, or prove it ain't happening with that setup.