Besides your standard Rate, Depth and Feedback knob and a Tap Tempo footswitch that’s now common on modulation pedals, the Phasia offers three LFO waves (sine, triangular, and the intriguing hypertriangular) that can be furtherly modified through a Simmetry knob.
On top of that, a Stages switch allows to increase the number of stages from 4 to 5 or six, for thicker results.
Here are the best videos of the Sitek Phasia.
Phasia ([/?fe???]) is a multi-stage OTA- based Phaser with a versatile feature set. It combines an all-analog moving filter section and a modern, tap-tempo controllable LFO that can go from stationary and resonant to fast and swirly.
It has a three way toggle LFO Shape switch to select between three different waveforms: hypertriangular, sine and triangular, which affects the character of modulation that can be further distorted by the Symmetry control.The Rate and Depth controls precisely set the speed of the LFO and the frequency the filters sweep- through.The flashing LED acts as a visual indicator for the LFO, reflecting the Rate, Depth and LFO Shape controls (even when the effect is in a bypass mode). The speed of the oscillator can also be set by pressing the Tap switch, allowing easy, 1/4 note tempo control while playing.
Stages switch allows the user to select 4, 5 or 6 moving filter stages which affects the overall voicing of the effect. The Feedback knob provides control over sending the phase-shifted signal back to the filter stages for more pronounced, resonant tone at higher settings to more subtle, classic phasing at lower setting.
All of these features make Phasia a comprehensive modulation effect.