The State Variable Filter is inspired by the Alembic SF-2 Super Filter. The SVF is a truly unique tone shaping pedal, capable of creating powerful EQ curves that would be otherwise impossible to acheive with a standard equalizer.
 
The SVF works by applying a filter to your signal, and allowing you to mix your filtered and direct signals together. The filtered signal goes through a state variable filter topology where you may choose a low pass, band pass, or high pass filter. The Frequency knob allows you to select the center frequency of effect for the filters. The resonance knob boosts the knee of the low and high pass filters, and makes the band pass either a cut or boost effect.
 
Mixing the direct and filtered signals can create a multitude of interesting tones:
 
Mixing the LPF signal with your direct signal can be like a boost to your low end, with a specific bump at the cutoff resonant frequency. This works amazingly well as a cab sim, or as a way to add heft to your tone. Being able to tune the frequency, the resonance, and volume of LPF signal to add makes the SVF a very powerful tone shaper for the low end.
Similarly, mixing the HPF signal with your direct signal can add brightness and clarity to your sound, again with the ability to bump the cutoff resonant frequency. This effect can be usefull for clearing up a muddy sound, or making a more cutting, aggressive tone.
Mixing the band pass filter signal is comparable to a variable semi parametric EQ, but still more powerful. By adding in the band pass filter, you are effectively adding a cut or boost of the specific frequency, with the width shaped by the resonance. With the resonance past noon, you are applying a boost at the center frequency, and below noon is a cut. 
 
The pedal requires a DC supply (not included). The supply must be at least 9V, but no greater than 24V. The current draw is 15mA. The connector must be a boss style, 2.1mm barrel, center negative polarity. A 24 volt power supply may be purchased separately
 
State Variable Filter has a true bypass switch.
 
Dimensions: 4.77" long x 2.6" wide