A master volume control next to the keyboard and power switch (it limits how loud you can go using the expression pedal). Sustain length controls for the upper- and lower-manuals, and the pedal board (it doesn't really go long enough for my liking though, and it probably can't considering the manuals are only eight-note polyphony and the pedal board can only play a single note at a time—you'd hear a sustained note get cut off instead of decay away, as soon as you'd played more notes than it can handle at a time). A length control for the percussive voices (e.g. how long the piano or vibraphone notes last, whether they're held down, released, or sustained). Reverb volume (the organ's got a small two-spring reverb unit). And a tremolo speed control.