Model 351 Omni Filter

The Omni Filter is OUT OF STOCK.

Please try the Borg Filters Module instead.


The Omni Filter is capable of 24 db per octave lowpass, 12 db per octave bandpass, 24 db per octave highpass and 720 degrees of allpass phase shifting. The input can be summed with the phase shifted output to produce the classic "Phase Shifter" comb filter. The audio input has a polarity switch which allows the bandpass mode to be summed with the input to produce "notch" filters.

The filter mode can be set under voltage control and the filter modes "morph" from one to another producing new intermediate filter type. This is a feature not available in any other system—either analog or DSP based. It has three exponential control inputs, calibrated 1 volt per octave, a simple attenuator and a "center zero" attenuator with positive and negative center frequency control available.  It also has an AC coupled linear modulation input with attenuator.

The Filter has a 12Db per octave output available simultaneously with the 24 db per octave output. A synthesized stereo output is generated with a differential amplifier. The Q (resonance) has a dedicated control and all modes support self-oscillation. The Q is voltage controllable with an attenuator for the "Q Modulation" input. Four LEDs indicate the filter mode and intermediate modes when more than one mode LED is illuminated. The output of the filter is displayed on a four LED VU meter.

The Omni Filter module contains:

• A four input mixer
• A unique multi-mode filter
• A jack multiple


Original User Manual