The Expert Sleepers Beatrix is a phaser, offering voltage control over notch frequencies, effect depth and feedback (resonance). It also offers an unusual 'offset' control allowing you to sweep the filter notches without sweeping the resonant frequency.

Further options are provided by the 'phase' switch (which disables the phasing sound and essentially turns the module into a resonant peak filter) and 'sum' switch (which inverts the filtered signal, giving a different flavour of phasing).

Beatrix will self-oscillate at high feedback if desired, though the front panel control is factory-trimmed to stop just short of self-oscillation. The module is 100% analogue, using discrete transistor OTAs.