Finally got round to plugging it in. Total silence. Twiddle the knobs, nothing, then I remember about the mute switch on my John East equipped Sei Jazz and switched the bottom switch - sound! The other two switches are parallel-series-single coil switches for the two pickups. Knobs are volume, blend, stacked treble/bass, stacked mid-sweep and boost/cut, and a pull for passive control that is also the passive treble cut control. A real variety of sounds available, and I may even be tempted to use the passive option on occasion. Despite the close pickup spacing, there's a fair difference between the tones on each of them (rather like the Warwick Thumb 5 with its two closely spaced J pickups). The treble and bass controls give a very powerful boost and cut but it's nicely progressive rather than all or nothing.