If you are only doing 9 faders, you'll only need 9 analog inputs. The AIN board (that's AIN, stryd :P ) is intended to multiplex 4 of the 8 analog inputs on the core board, creating up to 32 analog inputs (multiplexed) plus the other 4 non-multiplexed inputs. It works like this: [tt] +-----------------------------+ | Core Board | | 8 analog inputs | +-----------------------------+ | | | | | | | | 4 wires 4 wires | | | | | | | | +-------------+ +-------------+ | AIN Board | | AIN Board | |32 inputs, | |32 inputs, | |4 outputs | |4 outputs | +-------------+ +-------------+ [/tt] Or like this: [tt] +-----------------------------+ | Core Board | | 8 analog inputs | +-----------------------------+ | | | | | | | | 4 wires 4 non-mux inputs | | | | +-------------+ | AIN Board | |32 inputs, | |4 outputs | +-------------+ [/tt] If you only need 9 inputs, you could possibly do without some of the 4051s.