The modes are:
1) Normal Overdrive mode (OD mode):
This is the standard King Of Tone sound, which Jim like best- a little less drive available than a tube screamer. Factory DIP switch setting has this mode on the right side. This mode can get about 4 times louder than a tube screamer
if desired add a hi gain switch to choose the high gain and norm model
2) CLEAN mode :
This mode has less distortion, it can be used for clean boosts or clearer, louder sounds. It's sort of a cross between a true clean boost and an overdrive.
CLEAN MODE is even less compressed than the standard OD mode. The factory DIP switch setting uses this mode on the left channel. This mode can get twice as loud as the OD mode.
3) DISTORTION mode : This mode has more drive than the standard mode- a touch of hard distortion. The sound is more compressed, yet retains the pedal’s character. This mode can get almost twice as loud as a tube screamer. Distortion mode is not on either side with the factory DIP switch setting.
4)add a hi gain switch to choose the high gain and norm model.
