Empress Effects Multidrive - Manual (Page 7)

Configuring the Select Switch
The Multidrive allows you to toggle between two unique
combinations of the individual fuzz, overdrive and distortion
sections using the select switch. In each state you can combine one,
two, or all three sections together to create your own unique drive
sound.
To configure the settings, remove the back panel to access the
internal DIP switch. Here you can select which drive sections will be
turned on when toggling between state A and state B.
For example, with the DIP switch set as shown in the picture above,
the fuzz, overdive and distortion sections are on when the select
switch is set to state A. In state B, only the overdrive section is on.