DoepferA-106-6 XPander Filter

Doepfer A-106-6

If you want a truly multi-mode filter, the A-106-6 from Doepfer has you covered with 15 total different filter types available with eight simultaneous outputs. Based on the Oberheim Xpander / Matrix-12 filter, this filter provides a wide range of filtering types.

At the core is a 24dB/oct low pass filter. The four stages of this filter (6dB, 12dB, 18dB, and 24dB), are mixed in different amplitudes and polarities to create the 15 different filters. Due to the nature of the internal amplitudes and number of stages needed to create the filter, each of the filters have a slightly different amplitude and noise floor. Filters from a single stage tend to be less noisy than filters that combine multiple filter stages together. The eight outputs can be switched between the two filter groups using the filter group switch. The cutoff frequency of all filters can be controlled manually and with both attenuated and unattenuated CV inputs, the unattenuated CV input is useful for loosely tracking 1V/oct. In addition, the resonance, or Q can be controlled by external CV and several different filters in group 2 display self oscillating behaviors. Bringing together a wide selection of filtering types, this multi-mode filter really stretches the limits of how many modes one filter can have.

A-106-6 Features

• Multi-mode filter
• Comprised of a 24dB/oct low pass filter with the four stages combined in different amplitudes and polarities
• 15 total filtering types
• Eight outputs available simultaneously, with switch to select between the two groups
• Attenuated and unattenuated CV inputs
• CV over resonance
• 6dB low pass
• 12dB low pass
• 18dB low pass
• 24dB low pass
• 6dB high pass
• 12dB high pass
• 18dB high pass
• 6dB band pass
• 12dB band pass
• Notch
• All pass
• Asymmetric band pass from 12dB high pass and 6dB low pass
• Asymmetric bandpass made of 18dB high pass and 6dB low pass
• Notch/6dB low pass
• Combination all pass and 6dB low pass