Please, download and read the manual. I think you're misinterpreting the knobs or something.
The first volume knob acts on the pre-amp. This will be considered your "gain".
The treble knob also actually adds gain as well.
The higher the treble knob, the less affect the mid and bass knob will have.
The "master" is overall volume. For poweramp overdrive, lower settings of the first volume knob, and higher settings of the master willpush the power section.(This works great with a strat.)
lead drive is just that, an additional gain control for the lead channel only. This interacts with the first volume knob, or adds to it.
The lead master is to balance it with the clean and crunch (R1 & R2) channels.
On the back, the presence affects the output only, and will add highs to your outgoing signal. The reverb on these is just enough to let it breath some, not a Fender type reverb at all.
With the mid and lead knob pushed in, you'll have your clean channel, pull the mid knob for R2 (crunch/Marshally). Push the mid and pull the lead drive, and now you have your lead channel. Now, with the lead drive pulled, pull the R2. This adds gain and beef to your tone.
Pulling the Master, for "deep" is great for single coils, or to thicken up a bright guitar.
Pulling the treble affects the lead channel only, and adds high mids.
Pull the bass, and it expands the bass. I only pull it with very low settings of bass, like 0, or 1. Makes it fat...Too much makes it fart...
The pull bright on the lead master is for low volume playing, at high volume it'll squeel like a *****....
This is a hurried explanation or the controls, but may help. It takes getting used to, it's no Fender or Marshall, and is not something you figure out easily. But, once you get the hang of it, you can get a boatload of tones, they're all there...
Give us a clue as to what guitar you have, and what music you play.
I need to know what tones you're after. I can give you some optimum settings for each channel, and then some settings to toggle between all 3 channels.
Good luck!
ax. 8)