Hi, Recently went to a rehearsal room with my new "Band" (Only me and the singer turned up). I had to rent an amp because I couldn't transport my own. So the amp turned up and it had no dials on it. No volume knob either. I can just make out how to use normal amps with Volume, Mid, treble etc. But this had: A pre and post amp dial, Clean and distortion buttons, and Sliders (For wanting a better word) for the tone control. Because of this I had no idea how to use it and it took an hour of our practice for me to sort it out. Is there any advice any on could give me regarding this sort of amp.